Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11050122

Authors: Solange Milolo Tshilumba Ynke Larivière Trésor Zola Matuvanga Armand Mutwadi Danoff Engbu Germain Kapour Gwen Lemey Maha Salloum Maeliss Champagne Daddy Mangungulu Pierre Van Damme Hypolite Muhindo-Mavoko Vivi Maketa Tevuzula Joachim Mariën Martine Peeters Jean-Pierre Van Geertruyden Patrick Mitashi-Mulopo

Background: Malaria remains hyperendemic in the Democratic Republic of the Congo, while arboviral infections are increasingly reported but remain under-surveilled, particularly in remote regions. Overlapping ecological niches and non-specific clinical presentations complicate case management and surveillance. Methods: A cross-sectional door-to-door survey was conducted in December 2023 in Inkanamongo village (Lokolia Health Area, Boende Health Zone, Tshuapa Province). Blood samples were collected from 379 adults; malaria infection was assessed by using HRP2-based rapid diagnostic tests, and arboviral IgG antibodies were measured on dried blood spots using Luminex® multiplex immunoassay. Sociodemographic data were collected via standardized questionnaires. Results: Malaria prevalence was 51.7% (95%CI: 46.7–56.7). Overall arboviral seroprevalence reached 78.4% (95%CI: 73.1–81.5), dominated by O’nyong-nyong virus, 42.8% (95%CI: 37.6–47.5), Rift Valley fever virus, 32.0% (95%CI: 26.9–36.2), and chikungunya virus, 23.4% (95%CI: 19.0–27.4). Concurrent malaria infection and arboviral exposure were observed in 40.4% (95%CI: 35.6–45.4) of participants. No sociodemographic factors were significantly associated with co-exposure in the multivariable analysis. Conclusions: Substantial co-exposure of malaria and multiple arboviruses occurs in this remote Congo Basin setting.. Integrated surveillance and improved diagnostics are urgently needed to guide febrile illness management and preparedness in under-resourced regions.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11050121

Authors: Zhao Xuan Low Nghiem Nguyet Thu Truong Tuyet Mai Tran Thanh Duong Pouya Hassandarvish Vunjia Tiong Nguyen Thi Thu Thuy Nguyen Thi Tham Cap Minh Duc Osamu Kanauchi Sazaly Abubakar

The rising health threat to healthcare workers (HCWs) demands innovative preventive solutions that are affordable, scalable, and easy to deploy, especially in resource-limited settings. This present study investigated the effects of Lactococcus lactis strain Plasma (LC-Plasma) intake on upper respiratory infection (URI)-like symptoms in a healthy healthcare-associated population in Vietnam. A randomized, placebo-controlled, double-blind, parallel-group clinical trial was conducted, integrating clinical symptom analysis with ex vivo immune response analysis of peripheral blood mononuclear cells (PBMCs). The study found that after 4 weeks of continuous oral LC-Plasma intake, participants in the LC-Plasma group had significantly fewer cumulative days of fever and fatigue than those in the Control group. Increased expression of interferon-stimulated genes (ISGs), particularly MxA, was observed in PBMC cultures from the LC-Plasma intake group. In PBMCs from LC-Plasma recipients classified as low IFN-α responders, the addition of CpG ODN 2216, a mild TLR9 agonist, significantly enhanced interferon-α production. Humoral factors derived from LC-Plasma-primed PBMCs demonstrated inhibitory effects on dengue virus replication in Huh-7 cells. These results suggest that LC-Plasma consumption by the healthcare-associated population reduces the severity of viral infection symptoms, notably fever and fatigue. Elevation of systemic antiviral immunity through activation of plasmacytoid dendritic cells (pDCs) to produce IFN-α and upregulation of ISG expression could be the mechanisms of action. Lactococcus lactis LC-Plasma supplementation, hence, presents a promising adjunctive approach to alleviate the burden of URI-like symptoms in low-resourced vulnerable populations.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11050120

Authors: Tatjana Munko Vesna Vukičević Lazarević Jelena Barišić Marina Perković Tanja Vignjević

Objectives: Diagnostic delay in pulmonary tuberculosis remains a significant barrier to effective disease control, even in low-incidence settings. This study aimed to identify factors associated with total delay and its components among adults with pulmonary tuberculosis in such a setting. Patients and methods: A retrospective observational study was conducted on adults with pulmonary tuberculosis treated at a tuberculosis care centre in Croatia. Total delay was defined as the interval between symptom onset and treatment initiation. Data were collected through structured patient interviews using a standardized questionnaire, medical record review, and routine tuberculosis notification forms from the national public health registry. Sociodemographic and clinical predictors were evaluated using multivariable linear and logistic regression analyses. Results: Among 116 participants, the median total delay was 85 days (interquartile range 48.5–155.3). Rural residence was the strongest independent predictor, with patients experiencing an 88% longer delay than urban residents (p = 0.006). Individuals living in one-person households had a 49% longer delay (p = 0.047). Absence of chest pain was associated with shorter delay (−38%, p = 0.032) and lower odds of extreme delay (odds ratio 0.39, p = 0.047). Retired status independently predicted prolonged health system delay (42.1 days longer) and treatment delay (3.4 days longer). Conclusion: Prolonged delay may become increasingly important in the context of population ageing and changing household structures. Targeted strategies focused on rural, retired, and people living in one-person households may improve the timeliness of tuberculosis detection in settings where declining incidence can reduce clinical suspicion.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11050119

Authors: Andrés Esteban Barragán-Peña Darwin Paredes-Núñez Fabiola Jimenez Valenzuela Solon Alberto Orlando Elsy Carvajal Angel Sebastian Rodriguez-Pazmiño Miguel Angel Garcia-Bereguiain

Early confirmation of leptospirosis is essential for prompt antimicrobial treatment, and PCR-based diagnosis has been reported as a highly sensitive method during the acute phase in the first week since the symptom’s onset. We evaluated the diagnostic performance of two commercial real-time PCR assays—Viasure Leptospira Real-Time PCR (Certest Biotec, Spain) and Genesig Advanced Leptospira spp. (Primerdesign, UK) against an in-house qPCR assay targeting lipL32 as the reference method. A retrospective comparative evaluation was conducted on 235 human EDTA-blood samples obtained during the acute phase of clinical presentation suspected of leptospirosis. The in-house qPCR reference assay detected 55 positive and 180 negative samples, and both commercial kits accurately classified every specimen, achieving 100% sensitivity (95% CI: 93.5–100), 100% specificity (95% CI: 98.0–100), and 100% overall accuracy. In conclusion, both commercial qPCR kits offer high accuracy for the early detection of pathogenic Leptospira in human blood samples.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11050118

Authors: Penchom Janwan Lakkhana Sadaow Patcharaporn Boonroumkaew Rutchanee Rodpai Oranuch Sanpool Tongjit Thanchomnang Pokkamol Laoraksawong Pewpan Maleewong Intapan Wanchai Maleewong

Background: To address the significant burden of helminthiases in Thailand, this cross-sectional study compared the performance of a fecal parasite concentrator kit (FPCK) against the Kato–Katz (KK) method for diagnosing intestinal parasites in endemic populations across the Northeast and Southern regions. Methods: Stool samples were collected from 140 participants and examined for intestinal parasitic infections using both FPCK and KK methods. Results: The FPCK method demonstrated a significantly higher detection rate of 45.0% compared to 35.0% for the KK method. For detecting liver fluke (Opisthorchis viverrini), the FPCK method detected significantly more cases than the KK method (10.71% vs. 4.29%) (p = 0.0027). For other parasites such as Trichuris trichiura, Strongyloides stercoralis, and Entamoeba coli, the FPCK method tended to detect more infections, but the differences were not statistically significant (p > 0.05). Conclusions: The FPCK method showed better performance than the KK method for detecting intestinal helminth infections in stool samples, particularly O. viverrini, T. trichiura, S. stercoralis, and Entamoeba coli. Therefore, FPCK could be used as a suitable stool examination method for surveillance and monitoring of preventive treatment for opisthorchiasis.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11050117

Authors: Chumpol Anamnart Nawanwat Tepkidakarn

Meningovascular syphilis, a type of neurosyphilis, causes stroke and various types of myelopathy. In recent years, there has been an increase in the incidence of neurosyphilis. However, diagnosing neurosyphilis remains challenging due to the reliance on serum and cerebrospinal fluid (CSF) testing, which has low specificity and sensitivity. Magnetic resonance vessel wall imaging (MR-VWI), recently developed to identify vessel wall pathologies, may aid in diagnosing neurosyphilis. In this cross-sectional study, we performed systematic screening for syphilis in all 366 patients with acute ischemic stroke or transient ischemic attack admitted to our stroke unit. Further CSF analysis and MR-VWI were specifically conducted only on those with reactive serum venereal disease research laboratory (VDRL) or treponema pallidum particle hemagglutination assay (TPHA) tests to evaluate neurosyphilis. Serum screening was reactive in 5.7% (21/366) of patients; among these, the prevalence of likely neurosyphilis (defined by abnormal CSF pleocytosis or protein levels) was 2.2% (8/366). Within this group of eight patients, MR-VWI was technically feasible and thus performed in six cases. Although all CSF-VDRL tests were non-reactive, MR-VWI identified diagnostic evidence of meningovascular syphilis (concentric wall thickening and enhancement) in 33.3% (2/6) of symptomatic patients who underwent the scan. Neurosyphilis remains a critical, treatable cause of stroke that can affect older patients with established vascular risk factors. Our findings demonstrate that routine serum screening is essential, as traditional CSF-VDRL tests may yield false-negative results. MR-VWI serves as a valuable adjunct tool to provide objective evidence of active vasculitis, guiding the initiation of appropriate antibiotic therapy when laboratory results are inconclusive.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11050116

Authors: Tri Pudy Asmarawati Fikri Sasongko Widyatama Hari Basuki Notobroto Erwin Astha Triyono Nasronudin Nasronudin Motoyuki Sugai Kuntaman Kuntaman

Background/Objectives: Escherichia coli bacteremia is a major cause of morbidity, mortality, and healthcare expenditure. The increasing prevalence of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli (E. coli) complicates management and resource utilization. This study aimed to identify clinical predictors of higher hospital costs in E. coli bacteremia. Methods: We conducted a cross-sectional study of hospitalized patients with E. coli bacteremia in Surabaya, Indonesia (2022–2024). Hospital costs were categorized into bed costs, diagnostic costs, pharmacy costs, antibiotic costs, total costs, and daily costs. Costs were compared between ESBL and non-ESBL cases. Predictors of higher hospital costs were analyzed using generalized linear models with a Gamma distribution and log-link. Results: Among 209 patients, 131 (62.7%) had ESBL-producing E. coli. ESBL E. coli bacteremia was associated with significantly higher bed, diagnostic, pharmacy, total, and daily hospital costs than non-ESBL cases, while antibiotic costs were similar. ESBL E. coli bacteremia was associated with higher diagnostic and daily costs. High-care/ICU stay was the strongest predictor of increased costs. Pneumonia and infection source influenced cost components. Longer hospitalization increased total cost but reduced daily cost. Conclusions: Hospital costs in Escherichia coli bacteremia are driven by antimicrobial resistance, disease severity, and healthcare utilization. Targeted strategies such as antimicrobial stewardship and optimized critical care use are essential to reduce the economic burden.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11050115

Authors: Amanda Zanatta Berticcelli Andréa Lúcia Corso Pâmela Panassol Leticia Petersen Schmidt Rosito Roberta Rahal de Albuquerque Letícia de Paula e Souza Milena Lessa da Silva Sady Selaimen da Costa Luciana Friedrich

Background: Among the complications caused directly or indirectly by the Human Immunodeficiency Virus (HIV) are alterations in the auditory system. Children who are HIV-exposed but uninfected (HEU) appear to have a higher risk of hearing loss (HL) compared to their unexposed peers, but a lower risk than those infected with HIV. However, the literature remains inconclusive regarding this association. This study aims to evaluate the hearing function of HEU infants during the first months of life and to correlate these findings with maternal, gestational, and neonatal variables. Methods: This prospective cohort study included all HIV-exposed infants born in a quaternary hospital in southern Brazil between 2021 and 2023. Maternal, gestational, and neonatal data were collected, as well as the results of neonatal auditory screening. At approximately 6 months of age, otolaryngological and audiological assessments were performed, including wideband tympanometry and electrophysiological evaluation using Auditory Brainstem Response with frequency-specific stimuli. The prevalence of hearing loss refers to the number of infants affected. Results: Thirty-eight infants, with a mean age of 8 months (±3.3), completed the study. Of these, 1 (2.6%) presented with bilateral sensorineural HL, and 13 (34.2%) presented with conductive HL, with 6 cases being unilateral and 7 bilateral. No associations were found between hearing loss and maternal, gestational, or neonatal variables, except for maternal CD4 count, where higher CD4 cell counts were associated with an increased risk of conductive HL. Conclusion: The findings provide relevant data on auditory alterations in HEU infants, demonstrating a high prevalence of conductive HL. These results highlight the importance of monitoring the hearing of these children during the first years of life.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11050114

Authors: Awadh Alanazi Mohamed N. Ibrahim Mohamed A. Elithy

Despite prolonged viral inhibition with combination antiretroviral therapy (ART), HIV-1 survives as genetically intact, replication-capable proviruses within durable CD4+ T-cell fractions, involving central memory, transitional memory, and stem cell-like memory populations, as well as within tissue-resident compartments including lymphoid follicles and gut-associated lymphoid tissue. Reservoir stability is preserved via clonal growth of infected cells and epigenetic processes that impose proviral transcriptional silencing. As a result, current therapeutic approaches seek to either directly alter proviral survival or to improve immune-driven elimination of infected cells. At the molecular level, investigational strategies such as CRISPR–Cas9 and CRISPR–Cas12 gene-editing systems are intended to remove or induce inactivating mutations inside embedded proviral DNA, as well as alter host entrance co-receptors such as CCR5 to provide cellular resistance to infection. In addition, pharmacologic latency regulation is being studied via histone deacetylase inhibitors, protein kinase C agonists, and bromodomain inhibitors to reverse latency, along with Tat inhibitors and other transcriptional repressors aimed to persistently silence proviral expression. Moreover, immunological techniques aim to counteract inefficient endogenous antiviral defenses. Broadly neutralizing antibodies with tailored Fc-driven effector functions are under examination for both neutralization and antibody-dependent cellular cytotoxicity. Therapeutic vaccine approaches seek to elevate polyfunctional HIV-specific CD8+ T-cell responses, while adoptive cellular approaches, involving CAR-T cells aiming HIV envelope epitopes, remain in early clinical research. Immune checkpoint blockade is also being investigated to reverse T-cell depletion inside reservoir-rich tissues. Nevertheless, the key obstacles continue to be the diverse reservoir composition, restricted tissue penetration, viral escape, and safety limitations. The molecular and translational obstacles that characterize attempts toward an HIV cure must be addressed through ongoing multidisciplinary research.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11050113

Authors: Zichao Cao Yunan Gu Guoming Li Changsheng Deng

Malaria is one of the major global public health issues. An estimated 282 million malaria cases occurred worldwide in 2024, and the overall prevention and control progress has stagnated or even reversed in some regions. Mass drug administration (MDA), as a potential strategy to accelerate malaria elimination, has regained attention. This paper reviews the evidence base, controversial focuses, and application strategies of MDA in malaria prevention and control. It aims to promote its scientific application in the elimination phase. MDA plays an important role in malaria prevention and control. However, this strategy is accompanied by core limitations such as long-term drug resistance risks, insufficient implementation sustainability, and a high failure rate of regional adaptation. It also faces challenges from multiple common malaria species, as well as the newly discovered Plasmodium knowlesi. We therefore propose an “MDA+” collaborative strategy integrating vaccines, digital monitoring, and cross-border cooperation, so as to optimize resource allocation, achieve full coverage control over various malaria parasites, and advance the global malaria elimination process.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11050112

Authors: Rosa Nicole Freiberger Cynthia Alicia Marcela López María Belén Palma Cintia Cevallos Franco Agustin Sviercz Patricio Jarmoluk Marcela Nilda García Jorge Quarleri M. Victoria Delpino

The most common complication of active brucellosis in humans is osteoarticular injury. In the bone marrow microenvironment, mesenchymal stem cells (MSCs) can differentiate into either adipocytes or osteoblasts, and this balance is tightly regulated because an increase in adipogenesis may negatively affect bone formation and favor bone loss. The differentiation of MSCs into adipocytes or osteoblasts is tightly regulated by mechanisms that promote cell fate toward one lineage while repressing the other. Our study demonstrated that Brucella abortus infects MSCs but does not affect the deposition of organic and mineral matrix during osteoblast differentiation. However, the infection upregulates Receptor Activator of Nuclear Factor Kappa-B Ligand (RANKL) expression in osteoblasts, which may contribute to osteoclast activation and bone resorption. Conversely, B. abortus infection significantly influences adipocyte differentiation by modulating lipolysis, lipogenesis, and interactions between lipid droplets and mitochondria. This leads to increased cellular cholesterol levels and reduced intracellular triglycerides, accompanied by glycerol release. These changes result in more differentiated adipocytes and larger lipid droplets. Consequently, we observed increased IL-6 secretion and a higher leptin/adiponectin ratio. Importantly, these effects were independent of a functional type IV secretion system (T4SS), as purified Brucella DNA fully reproduced the adipogenic phenotype. Moreover, inhibition of TLR9—the primary sensor of bacterial DNA—significantly reduced the DNA-induced adipogenic response, demonstrating that adipocyte modulation is at least in part mediated through TLR9 signaling. In summary, B. abortus promotes MSC differentiation toward an inflammatory adipocyte phenotype. It involves a TLR-9-mediated DNA detection. It may contribute to osteoarticular injury and infection-associated bone resorption.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11050111

Authors: Paulina Garzaro Carmen Castillo Natalie Fahsen Lucas Santos Joyce Lu Christiana Hug Matthew Lozier Douglas R. Call Celia Cordón-Rosales Brooke M. Ramay

Introduction: Healthcare-associated infections are a significant public health challenge, particularly in resource-limited settings. While hand hygiene is critical for infection prevention, contaminated water from hand hygiene stations (HHSs) in healthcare facilities (HCFs) may undermine infection control efforts. Chlorination can reduce microbial contamination in HHSs, ensuring that water intended for hygiene does not become an infection source. Methods: Water quality was monitored before and after the installation of on-site chlorine dispensers (CDs) in water tanks and HHSs of HCFs in Quetzaltenango, Guatemala, to evaluate their effectiveness in improving water quality. Focus groups were conducted to develop action plan proposals to ensure the intervention’s sustainability. Results: Before the intervention, 75% of HHS water samples tested positive for total coliforms, with 50% testing positive for presumptive extended-spectrum beta-lactamase (ESBL)-producing total coliforms, while 20% were E. coli-positive, with 50% presumptive ESBL-producing E. coli. After installing CD, 1% of samples were coliform-positive over a six-month period. Focus groups identified resource limitations and political barriers and proposed solutions such as developing operational manuals, strengthening inter-institutional relationships, and forming alliances with external organizations. Conclusion: Localized chlorination was successfully implemented using a community participatory approach to improve water quality in resource-limited HCFs. These findings have important implications for infection prevention and control.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11050110

Authors: Gianluca D’Amico Carmen Costache Calin Gherman Ioana Cristina Ilea Adriana Györke

Furuncular myiasis is rarely reported in Southeast/Eastern Europe and may be underrecognized or misdiagnosed in non-endemic settings. We described two imported furuncular myiasis cases diagnosed in Romania following travel to Peru and confirmed the etiologic agent by larval morphology and mitochondrial cytochrome c oxidase subunit I (COI) sequencing. We also conducted a narrative review of published case reports/series from Southeast/Eastern Europe (1900–2025) and summarized case characteristics. A previously healthy 31-year-old woman and 32-year-old man presented with painful furuncle-like lesions on the upper back near the shoulder and the posterolateral upper arm, respectively, associated with pruritus and a sensation of movement. Each lesion had a central punctum with intermittent air bubbles. Occlusion of the breathing pore with petroleum jelly facilitated mechanical extraction of one barrel-shaped larva per lesion. Microscopy showed features consistent with second-instar Dermatobia hominis larvae, and COI sequencing demonstrated 97.14–99.33% identity with reference D. hominis sequences. Literature review identified 25 travel-associated cases, with D. hominis involved mostly after travel to Central/South America. These cases highlight the value of travel history and key diagnostic clues for D. hominis myiasis in travelers that may enable timely diagnosis and minimally invasive management. Greater awareness and reporting are needed to better define epidemiology.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11040109

Authors: Mohamed Haidy Massa Mohamed Aly Ould Lemrabott Osman Abdillahi Guedi Nicolas Gomez Sébastien Briolant Ali Ould Mohamed Salem Boukhary

Aedes aegypti, the main urban vector of dengue fever, poses a major public health problem in Nouakchott, Mauritania. This study analyzed the host-seeking and sugar-feeding behaviors of Ae. aegypti. Mosquitoes were collected using a vacuum cleaner in four districts between December 2023 and October 2024. Biting activity on humans was studied in May 2024, exclusively in the districts of Ksar, Tevragh Zeina and Arafat, between 5:00 a.m. and 9:00 p.m. A negative binomial model was performed to analyze the effect of location and time on the human biting rate (HBR) of mosquitoes. In Nouakchott, except in the Arafat district, Ae. aegypti bites occur mainly outdoors, between 8:00 a.m. and 1:00 p.m., with a peak between 11:00 a.m. and noon (HBR = 20 bites/person), and between 5:00 p.m. and 7:00 p.m., with a peak between 6:00 p.m. and 7:00 p.m. (HBR = 11 bites/person). Inside homes, Ae. aegypti biting activity remains low everywhere (HBR ≤ 1.5 bites/person/hour). Molecular analysis of the origin of the blood meals showed that the females collected in Nouakchott were exclusively anthropophilic. Molecular analysis of the sugar sources revealed a great diversity with sweet potato being among the most common. These results highlight the need for targeted outdoor interventions and larval control measures to reduce the risk of dengue transmission in Nouakchott.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11040108

Authors: Fouad Ibrahim Alshehri Dhaifullah Ahmed Alkhosafi Essam Abdullah Al Asmari Abdulrahman Bin Saeed Anas Mohammed Zarbah Saeed Ali Algarni Mohammed Gasim Ahmed Marim Abdallah Mohamed Fatma Anter Mady Saleh Mohammed Zafer Albakri Ramy Mohamed Ghazy

Background: Saudi Arabia has made significant progress toward malaria elimination; however, imported cases continue to occur, particularly in the southwestern regions. This study aimed to describe the clinical characteristics and outcomes of patients with malaria in the Aseer Region, Saudi Arabia. Methods: A retrospective observational study was conducted at Khamis Mushait General Hospital, Aseer Region, Saudi Arabia, including all patients with malaria from January 2022 to December 2025. Demographic, clinical, laboratory, and outcome data were extracted from the electronic medical records. Severe malaria was defined according to the World Health Organization criteria. Multivariate logistic regression using Firth’s penalized maximum likelihood estimation was performed to identify independent predictors of severe malaria (≥1 WHO criterion). Statistical analysis was performed using R software (version 4.2.1). Results: A total of 311 patients were included, predominantly male (90.0%), with a mean age of 28.8 ± 11.3 years. Ethiopian nationals comprised nearly half the cases (48.2%), followed by Saudi (16.4%) and Yemeni (15.1%) nationals. Plasmodium vivax was the most common species (51.1%), followed by Plasmodium. falciparum (40.2%). Fever was the most frequent symptom (89.4%), followed by fatigue (50.8%), chills (46.9%), and vomiting (39.5%). Low parasitemia (<1%) was the most frequent finding (33.8%), followed by moderate (27.3%) and mild (18.3%) levels, while high (4.2%) and very high parasitemia (1.9%) were uncommon. Severe malaria (≥1 criterion) was diagnosed at 43.7%, with severe anemia (26.0%) and jaundice (23.2%) being the most frequent WHO severity criteria. Notably, 84% of the cases occurred during 2024–2025, indicating a recent outbreak, with a sharp peak of 43 cases in October 2024. Multivariate logistic regression identified two independent predictors of having at least one WHO severity criterion: higher parasitemia level (adjusted OR = 1.70 per 1% increase, 95% CI: 1.40–2.11, p < 0.001) and non-Saudi nationality (adjusted OR = 2.40, 95% CI: 1.10–5.62, p = 0.027). Conclusions: Malaria in the Aseer Region predominantly affects young adult male expatriates, suggesting its imported nature. The predominance of P. vivax represents a shift from historical patterns. Parasitemia level and being of non-Saudi nationality independently predict severe malaria and may therefore support risk stratification and clinical decision-making. The dramatic case surge in 2024–2025 highlights regional vulnerability to outbreaks despite control progress. These findings support enhanced screening for at-risk populations, maintenance of clinical capacity for severe malaria management, and robust surveillance systems for early outbreak detection.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11040107

Authors: Cansel Askin Behcet Al Cihad Unsal Karahaliloglu Yunus Emre Gemici Ibrahim Coban Abdulkerim Emre Yanar

Background: Rabies remains a major zoonotic disease worldwide, particularly in regions with large populations of free-roaming animals. In urban settings, animal-related injuries constitute a substantial healthcare burden and frequently result in the administration of rabies post-exposure prophylaxis (PEP). This study aimed to evaluate the epidemiological characteristics of animal exposures and real-world PEP practices in a metropolitan emergency department. Methods: This retrospective descriptive study included 1960 patients presenting to a tertiary metropolitan emergency department between 1 March and 1 September 2025 with suspected animal exposure. Demographic data, animal species involved, exposure mechanisms, animal ownership and vaccination status, time to presentation, and PEP practices were analyzed using descriptive statistics. Results: Most exposures were cat-related (86.3%) and were caused by scratching (81.5%). Nearly all injuries were superficial (99.8%), while deep injuries were rare (0.2%). The majority of animals were classified as strays (90.1%), and vaccination status was unknown in 81.2% of cases. Rabies immunoglobulin was administered to only 0.6% of patients; however, rabies vaccination was initiated in 98.8% of patients. Approximately 74.5% of patients presented within 24 h. Post-exposure animal observation was documented in only 20.2% of cases. Conclusions: Urban animal exposures in this metropolitan setting were predominantly superficial and cat-related, yet nearly all patients received rabies vaccination. Limited animal observation and incomplete vaccination documentation appear to constrain risk stratification and may contribute to the use of precautionary PEP. Strengthening surveillance systems, improving documentation, and implementing evidence-based risk-stratification strategies are essential for optimizing rabies prophylaxis practices in urban environments.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11040106

Authors: Josephine Abrazaldo Patrick de Vera Sheila Grace Martin John Leo Dayrit Daryl Christian Mejos Ferdinand Mortel

Neglected tropical diseases (NTDs) such as soil-transmitted helminthiasis, lymphatic filariasis, schistosomiasis, leprosy, rabies, and food-borne trematodiasis are endemic in the Philippines. Despite global and national elimination efforts, these six NTDs remain a persistent burden to the poor, those living in Geographically Isolated and Disadvantaged Areas (GIDAs), and other vulnerable groups. This narrative review synthesized data from Field Health Services Information System (FHSIS) reports of the Philippine Department of Health (DOH) from 2020 to 2024, the available literature from electronic databases, and DOH and WHO reports focusing on the challenges, barriers, and gaps in NTD control and elimination in the country. Core challenges include complex epidemiological landscapes, lapses in disease surveillance, infrastructure, and fragmented health care systems. Gaps include access to diagnostics, insufficient funding and human resource training, and scarcity of local studies focusing on endemic NTDs. With these challenges and gaps, this review highlights the need for a real-time feedback loop system in surveillance strategy, community-based interventions, full integration of NTDs in primary health care, and collaboration between government, NGOs and private entities. Addressing these challenges and gaps is key to shifting from control to elimination.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11040105

Authors: Jérôme Munyangi wa Nkola Pierre Akilimali Zalagile Hendrick Lukuke Mbutshu Spartacus Kabala Munyemo Imani Ramazani Bin Eradi Alioune Camara

Background: The Democratic Republic of the Congo accounts for approximately 12–13% of the global malaria burden. While international guidelines oppose the use of Artemisia annua infusions due to risks of sub-therapeutic dosing and resistance selection, the plant remains widely used in resource-limited regions. This study evaluates the clinical acceptability and perceptions of healthcare providers regarding the integration of Artemisia annua tea into formal malaria control in the Maniema province. Methods: A cross-sectional survey was conducted among 337 healthcare professionals in the Kalima health district using the KoboCollect digital platform. Multivariate logistic regression was employed to identify the primary socio-professional determinants of clinical acceptability. Results: The overall clinical acceptability of Artemisia annua integration was 81.0%, with 82.8% of providers perceiving the preparation as effective. Rural residency was the strongest predictor of adherence (AOR = 6.847; p = 0.003), reflecting a pragmatic response to frequent ACT stockouts and high treatment costs. Despite high acceptability, 49.0% of providers identified the lack of clinical evidence as a major barrier, and 91.4% demanded formal training on standardized dosage and biological mechanisms. Conclusions: A significant “policy–practice gap” exists between international guidelines and field realities in the DRC. Healthcare providers demonstrate high readiness for integration but emphasize the absolute necessity of galenic standardization to mitigate resistance risks. To address these concerns, a complementary genomic investigation is currently underway in the same study area, comparing PfKelch13 mutation prevalence among Artemisia tea users versus ACT-treated patients. This molecular surveillance will provide essential evidence to define safety parameters for future phytopharmaceutical integration.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11040104

Authors: Cherotich Jesca Tangus Ndichu Maingi James Chege Nganga Davis Karanja Njuguna Kariuki Njaanake Bruno Enagnon Lokonon Gloria Ivy Mensah Kennedy Kwasi Addo Andrée Prisca Ndjoug Ndour Bassirou Bonfoh

Toxoplasmosis is a widely distributed zoonosis caused by the protozoan parasite Toxoplasma gondii. Infection during pregnancy is a major public health concern due to its potential impact on both maternal health and fetal development. Early detection of maternal infection is critical to prevent adverse outcomes; however, maternal signs are often subtle, non-specific or absent, complicating timely diagnosis. This scoping review aimed to map and synthesise existing evidence on early maternal signs, pregnancy and foetal outcomes, frequently assessed risk factors, and diagnostic approaches of toxoplasmosis in expectant mothers in Africa. The review was done in accordance with the PRISMA-ScR guidelines. A literature search of PubMed, Scopus, ResearchGate, and Google Scholar was performed to identify studies published between 2000 and 2025. Retrieved records were managed using Zotero (version 8.0.4) for deduplication and screening. Only English-language studies conducted in Africa and reporting relevant maternal or clinical data were included. A total of 28 cross-sectional studies were included. Lymphadenopathy (25.0%) was the most frequently reported maternal early sign, followed by flu-like illness, asymptomatic infection, low-grade or mild fever, and fatigue or malaise (each 10.7%). Congenital anomalies (50.0%) and miscarriage or spontaneous abortion (42.9%) were the most commonly reported foetal and pregnancy outcomes. Frequently reported risk factors were exposure to cat faeces (57.1%) and ingestion of undercooked or raw meat (42.9%). Diagnostic approaches were commonly enzyme-based immunoassays (78.6%), with limited use of RDTs and molecular methods. These findings suggest the need for improved early detection and prevention strategies in high-risk, low-resource African settings. Enhancing routine screening, health education, and access to appropriate diagnostics are considered. Future studies should consider adopting standardised reporting and integrating sensitive, affordable, rapid diagnostic approaches to enhance early detection and reduce the burden of congenital toxoplasmosis.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11040103

Authors: Shuai Wei Xinyan Chen Shangkun Cai Xiaoqin Li Ting Lu Yaoting Li Yuanlin Hou Yanwen Li Yunliang Shi

Background: Cysteine proteases of Clonorchis sinensis are potential diagnostic antigens, yet the performance of individual members within this diverse enzyme family requires systematic evaluation. This study aimed to assess the diagnostic potential of four recombinant cysteine proteases (rCsCP1–4) for human clonorchiasis. Methods: An indirect ELISA was developed to measure serum reactivity (IgG, IgG subclasses, IgA) against rCsCP1–4. The assay was validated using 180 microscopy-confirmed positive and 148 negative control sera. Samples were randomly split into training and validation sets (7.5:2.5). Diagnostic performance of single antigens and their combinations was evaluated using univariate and multivariate logistic regression and compared with a commercial kit. Key metrics included the area under the curve (AUC), sensitivity, specificity, accuracy, F1-score, and Kappa coefficient. Results: Four single antigen–antibody pairs showed high performance: rCsCP1-IgG4 (AUC = 0.928), rCsCP2-IgA (AUC = 0.863), rCsCP3-IgG1 (AUC = 0.920), and rCsCP4-IgG4 (AUC = 0.958). Among these, rCsCP1-IgG4, rCsCP3-IgG1, and rCsCP4-IgG4 outperformed the commercial kit, achieving higher sensitivity (92.0%, 96.0%, 96.0% vs. 86.0%), specificity (87.5%, 81.3%, 90.6% vs. 78.1%), accuracy (92.0%, 88.9%, 94.1% vs. 86.0%), and F1-scores (0.902, 0.902, 0.939 vs. 0.829). The Kappa values for rCsCP1-IgG4 (0.768) and rCsCP4-IgG4 (0.773) indicated substantial agreement with the microscopic standard. Multi-antigen combinations (triple or quadruple) further enhanced performance, achieving sensitivity and specificity > 98% with an AUC approaching 1.0. Conclusions: This study identifies rCsCP1 and rCsCP4, particularly in combination with IgG4 detection, as highly promising diagnostic targets for clonorchiasis. Multi-antigen combinations significantly improved diagnostic performance compared to single-antigen assays, offering a strategy for high-precision diagnosis. Furthermore, the efficacy of the rCsCP2-IgA pair suggests that detecting fecal secretory IgA could be a novel avenue for non-invasive, self-testing applications.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11040102

Authors: Yazdan Mirzanejad

As we conclude this set of ten publications in Tropical Medicine and Infectious Disease, three clear themes emerge to the surface [...]

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11040100

Authors: Ivy Rukasha Kabelo Gabriel Kaapu

Background: Drug-resistant tuberculosis (DR-TB) continues to pose a major challenge in Limpopo Province, a predominantly rural region of South Africa with high prevalence of HIV and mobility of the cross-border population. Despite the scale-up of short all-oral bedaquiline-based regimens, there is limited recent provincial evidence describing DR-TB epidemiological characteristics and treatment outcomes in the post-COVID-19 period. This study aimed to assess resistance patterns, treatment outcomes, and factors associated with unfavorable outcomes among patients with DR-TB in Limpopo Province from 2020 to 2024. Methods: A retrospective cohort study was conducted using routinely collected data from the Electronic Drug Resistant Tuberculosis Register (EDRWeb). All laboratory-confirmed DR-TB cases diagnosed between January 2020 and December 2024 were included. Descriptive statistics were used to summarize demographic and clinical characteristics. Multivariable logistic regression was performed to identify predictors of unfavorable outcomes (treatment failure, death, and loss to follow-up). Kaplan–Meier survival analysis was used to estimate survival probability following treatment initiation. Results: A total of 1240 DR-TB cases were recorded, of which 1165 (94%) had documented treatment outcomes. Rifampicin-resistant TB (RR-TB) predominated throughout the study period, accounting for 76% (951/1240) of cases and remaining stable over time. Treatment success improved from 173/260 (67%) in 2020 to 130/166 (78%) in 2024, while loss to follow-up declined from 34/260 (13%) to 4/166 (2%). Kaplan–Meier survival analysis showed that mortality occurred predominantly during the early phase of treatment. Patients receiving bedaquiline-containing regimens demonstrated significantly higher survival probability compared with those not receiving bedaquiline (log-rank p = 0.024; HR 0.58, 95% CI: 0.35–0.94). In multivariable analysis, HIV infection was independently associated with unfavorable outcomes (aOR 1.36; 95% CI: 1.04–1.77; p = 0.025), while increasing age showed a modest association with poorer outcomes. Conclusions: Treatment outcomes for DR-TB improved over the study period, accompanied by declining loss to follow-up and improved survival. The survival advantage observed among patients receiving bedaquiline-containing regimens supports continued prioritization of bedaquiline-based treatment strategies in DR-TB management. Strengthening access to these regimens, alongside integrated HIV care, may further improve treatment outcomes in Limpopo Province and similar high-burden settings in South Africa.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11040101

Authors: Asanka R. DeZoysa Madeline Kwan Lekshmi K. Edison Rebecca Barber Lisa Glick Thomas Denagamage Subhashinie Kariyawasam

Uropathogenic Escherichia coli (UPEC) is a leading cause of urinary tract infections (UTIs) in companion animals. This study characterized 42 UPEC isolates recovered from dogs and cats at the University of Florida, College of Veterinary Medicine Diagnostic Laboratories between 2023 and 2024, focusing on antimicrobial resistance (AMR), virulence gene profiles, biofilm-forming ability, and phylogroup distribution of the isolates. Antimicrobial susceptibility testing (AST) showed that 40.48% of the isolates were resistant to at least one of the tested antibiotics, and 9.52% exhibited multidrug resistance (MDR). Phylogroup B2 was predominant (69.05%), and 61.90% of isolates demonstrated strong biofilm formation in artificial human urine. Virulence gene analysis revealed the presence of genes mediating adhesion (fim, pap, sfa), iron acquisition (fyuA, iro), biofilm formation (csg, bcs, pga, ycg/ymg), motility (fli, mot, flh), and stress response (oxyR, soxR/S, kat). Multiple plasmids carrying AMR and virulence determinants were also identified. The co-occurrence of the traits underscores the potential for persistent and recurrent infections, which can complicate therapeutic outcomes and facilitate horizontal gene transfer (HGT). The detection of antimicrobial-resistant, highly virulent UPEC strains possessing human UPEC traits in companion animals suggests the risk of zoonotic and reverse-zoonotic transmission, particularly in households with close pet–owner interactions. These findings emphasize the importance of judicious antimicrobial use, routine molecular surveillance, and integrated One Health strategies to mitigate the veterinary and public health threats associated with UPEC infections in companion animals.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11040099

Authors: Ngoan Tran Le Ngan Dieu Thi Ta Quyet Quang Nguyen Thanh C. Bui Joshua T. Mattila Suresh V. Kuchipudi Toan Ha

Tuberculosis (TB) remains a major public health burden in Vietnam, yet few studies have examined pulmonary TB mortality trends at sub-national levels, where local epidemiological patterns may differ substantially from national averages and reveal high-risk populations requiring targeted interventions and inform resource allocation. Lang Son, Vietnam, is a mountainous border province with many ethnic minority residents, and extensive cross-border movement creates distinct challenges for TB surveillance and treatment adherence. Although mortality has declined in line with national trends, rates in this border province remain higher than those in Vietnam’s major urban centers. This disparity suggests a hidden burden where Lang Son’s unique geographic challenges and ethnic diversity create health inequities that are often obscured by favorable national-level averages. To better understand local epidemiological patterns, this study examined temporal trends and gender differences in pulmonary TB mortality in Lang Son Province over a 12-year period (2005–2008 and 2011–2018). Using data from a population-based mortality registration system, we calculated crude and age-standardized mortality rates (ASR) per 100,000 person-years. Temporal trends were assessed using Poisson regression. The overall ASR was 7.7 per 100,000 person-years among men (95% CI: 6.5–9.0) and 1.9 among women (95% CI: 1.3–2.7), yielding a male-to-female ASR ratio of 4.1. The age-standardized pulmonary TB mortality declined by approximately 49.2% (from 6.3 (95% CI: 4.1–9.2) to 3.2 (95% CI: 1.9–4.9) per 100,000 person-years; p = 0.025). Notably, 69.9% of deaths occurred in individuals under age 70. While declines were observed in both sexes, sex-specific temporal trends were not statistically significant (p > 0.05). Despite these improvements, persistently higher mortality among men and older adults highlights ongoing inequities in TB outcomes within the province. These pre-pandemic findings provide an essential epidemiological baseline for assessing COVID-19’s impact on TB control and underscore the need for age- and gender-targeted interventions at sub-national levels to accelerate Vietnam’s progress toward TB elimination.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11040098

Authors: Andrea Romero-Magaña Carlos Chacón-Díaz Alejandro Alfaro-Alarcón Marcela Suárez-Esquivel Esteban Chaves-Olarte Gabriela Hernández-Mora Edgardo Moreno Elías Barquero-Calvo

Members of the genus Brucella are bacterial pathogens of global importance, and their increasing detection in marine mammals has raised concerns for wildlife conservation and public health. In this study, we evaluated the biological and pathogenic characteristics of two Brucella sp. sequence type 27 (ST27) isolates obtained from a dwarf sperm whale (Kogia sima). We compared them with terrestrial and marine Brucella reference strains. We assessed resistance to polymyxin B and human serum complement, intracellular infection dynamics in HeLa epithelial cells, persistence in a murine model, and associated hematological and histopathological changes, and analyzed lipopolysaccharide (LPS) profiles. The Kogia isolates exhibited resistance to polymyxin B and serum complement, comparable to that of B. abortus 2308W and marine mammal Brucella strains. In HeLa cells, the isolates displayed distinct, strain-specific intracellular infection dynamics. In the murine model, both isolates persisted in the spleen and induced granulomatous lesions. However, splenic bacterial loads and histopathological scores were generally lower than those observed with B. abortus 2308W, which exhibited the highest virulence among the strains evaluated. Hematological alterations associated with Kogia isolates were also less pronounced than those induced by B. abortus 2308W, indicating an intermediate and strain-dependent virulence phenotype without evidence of enhanced virulence relative to the terrestrial reference strain. Western blot analyses showed that Brucella sp. ST27 isolates were not recognized by anti-B. abortus or anti-O-antigen monoclonal antibodies, while exhibiting a distinct recognition pattern with anti-B. canis serum, indicating differences in surface antigen composition. Comparative whole-genome analysis identified a limited number of isolate-specific variants affecting coding and intergenic regions. Collectively, these findings highlight phenotypic and genetic features of Brucella sp. ST27 from Kogia sima, which distinguishes it from other marine and terrestrial Brucella strains and supports further investigation into its biological behavior and potential public health relevance.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11040097

Authors: Constantinos Tsioutis Marcin Piotr Walkowiak

Paraphrasing T [...]

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11040096

Authors: Hai Xu Yanxiong Wang Lin Mi Li Ren Zhixin Wang

Alveolar echinococcosis (AE), caused by Echinococcus multilocularis larvae, is a severe zoonotic disease mimicking tumors, primarily affecting the liver with high mortality if untreated. Host immunity plays a pivotal role, shifting from Th1/Th17-mediated clearance to Th2/Treg-driven tolerance, enabling parasite survival. Liver macrophages, including Kupffer cells, polarize towards M2 phenotype under parasite antigens (e.g., phytic acid, exosomes), promoting immunosuppression, fibrosis, and T cell exhaustion via IL-10/TGF-β. This reshapes the tumor-like immune microenvironment with M2 macrophages recruiting Tregs, suppressing NK/DC functions, and fostering angiogenesis/fibrosis. Current treatment remains centered on surgery and benzimidazole therapy, both of which have notable limitations. Experimental immunomodulatory strategies, drug repurposing approaches, and targeted delivery systems may offer future therapeutic opportunities, but these concepts remain largely preclinical, unproven in AE, and require careful evaluation for safety and efficacy.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11040095

Authors: Renata Santos de Sousa Lorena de Carvalho Corrêa Fabiola Santos da Silva Matos Samia Meneses dos Santos Marcos Daniel Mendes Padilha Carolina Cabral Angelim Álesson Adam Fonseca Andrade Amanda Roberta Vieira Sacramento Aline Cecy Rocha de Lima João Lukas Nunes Almeida Mauro Sérgio Moura de Araújo Vitória Sahena Martins Souza Barbosa Jacqueline Cortinhas Monteiro Greice de Lemos Cardoso Costa Andréa Nazaré Monteiro Rangel da Silva Simone Regina Souza da Silva Conde Luiz Fernando Almeida Machado Izaura Maria Vieira Cayres Vallinoto Antonio Carlos Rosário Vallinoto Rosimar Neris Martins Feitosa

Coinfection between hepatitis C virus (HCV) and human T-lymphotropic virus 1/2 (HTLV-1/2) remains poorly investigated in the Northern Region of Brazil despite its clinically important condition. The objective of this study was to determine the prevalence and describe the epidemiological and behavioral risk factors for HCV/HTLV-1/2 coinfection in Belém, Pará. This observational, descriptive, and cross-sectional study analyzed 192 samples from patients previously diagnosed with HCV: 127 participants recruited between May 2023 and June 2025 and 65 samples previously stored in the Virology Laboratory of UFPA. Data were collected through a structured survey. Serological screening for HTLV-1/2 was performed by enzyme-linked immunosorbent assay (ELISA) and confirmed by INNO-LIA and molecular biology (qPCR). HCV/HTLV-1/2 coinfection was observed in 4 individuals (2.1%), of whom 1.6% had HCV/HTLV-1 coinfection and 0.5% HCV/HTLV-2. There was no statistically significant association when comparing the sociodemographic, clinical characteristics, or risk factors of HCV monoinfected and HCV/HTLV-1/2 coinfected individuals. Although the results show a low prevalence of HTLV-1/2 and HCV coinfection in Belém do Pará, they still reinforce the importance of including HTLV in testing protocols for patients with hepatitis C in the North region of Brazil.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11040094

Authors: Sonia Menon Anthony D. Harries Riitta A. Dlodlo Gisèle Badoum Mohammed F. Dogo Olivia B. Mbitikon Pranay Sinha Yan Lin Jyoti Jaju Aung Naing Soe Anisha Singh Bharati Kalottee Kobto G. Koura

Background: Tuberculosis (TB) remains a major global health threat, particularly in low- and middle-income countries, with TB infection (TBI) serving as the primary source of TB disease. While HIV infection has long been recognised as a major risk factor for TB progression, the rise of Non-Communicable Diseases (NCDs), which may exert immunosuppressive effects, further compounded by their treatment, contributes to increased TB susceptibility. This scoping review synthesises evidence from systematic reviews on medical and behavioural risk factors for TBI progression to TB disease, for both asymptomatic and symptomatic disease. Methods: A preliminary literature search was conducted on 11 January 2025, in PUBMED using the keywords “tuberculosis,” “asymptomatic or subclinical tuberculosis” “risk factors,” and “systematic review” followed by targeted reviews on the identified medical and behavioural risk factors for TB infection progression to TB disease. Results: A total of 25 systematic reviews were included. Medical risk factors for progression from TB infection to TB disease included diabetes mellitus (DM), chronic kidney disease (CKD), chronic obstructive pulmonary disease (COPD), undernutrition (including iron and vitamin D deficiency), cancer—particularly haematological malignancies—and immunosuppressive therapies (TNF-α inhibitors and glucocorticoids). Iron and vitamin D deficiency, particularly severe deficiency, is linked to increased TB risk, especially among people living with HIV. Behavioural risk factors, including tobacco, drug, and alcohol use, were also highlighted. Geographic variations in TB prevalence, diagnostic practices, and healthcare systems contributed to differences in risk estimates across reviews. No systematic reviews were identified that examined risk factors for asymptomatic TB. Conclusions: The convergence of TB with NCDs, compounded by immunosuppressive therapies, poses a public health challenge in high TB burden settings. Effective TB prevention requires targeted screening, along with enhanced management of these NCDs. Nutritional support, particularly screening and treatment of anaemia and vitamin D deficiency, may benefit individuals with TBI, comorbid NCDs, and HIV. A multidisciplinary approach, integrating behavioural interventions and tailored prevention strategies, is essential to achieving WHO’s End TB targets. Addressing the evidence gap on risk factors for asymptomatic TB is also critical to improve early detection and interrupt transmission.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11040093

Authors: Paloma Camacho-Aguilar Leobardo Daniel Gonzalez-Zuñiga Jose Reyes Gonzalez-Galaviz Fernando Lares-Villa Luis Fernando Lares-Jiménez Luis Fernando Lozano Aguirre Beltrán Alejandro Otero-Ruiz Libia Zulema Rodriguez-Anaya

Acanthamoeba is a free-living amoeba (FLA) that causes the majority of human infections. It is found predominantly in aquatic environments and is classified according to morphology or genotype (T1-T23). Research on this FLA aims to monitor its distribution, identify existing genotypes, assess its infectious potential, and identify factors that contribute to its recurrence. This study performed a molecular characterisation of Acanthamoeba strains isolated from tap water in Cajeme, Sonora, Mexico, to classify their genotypes. This was complemented by whole-genome sequencing and mapping of the 18S rRNA region in a divergent strain, LUDO1, to obtain higher-resolution data for more reliable assessment of its divergence from known genotypes. Genotypes T4, T5, T11, and T15 were identified in the Acanthamoeba-specific amplimer S1 (ASA.S1) region using the maximum-likelihood method. The inclusion of the 18S rRNA region from strain LUDO1 enabled its classification as a new genotype (T24), with a dissimilarity exceeding 5% compared with the 23 known genotypes. Additionally, culture analysis revealed notable variation in trophozoite size among strains that correlated with phylogenetic sub-branching. This analysis contributed to the epidemiological understanding of Acanthamoeba’s high resistance to treatments and infection systems and demonstrated a broadening of the phylogenetic distribution within the genus.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11040092

Authors: Alfonso J. Rodríguez-Morales Katherine Acevedo-Jimenez María Eugenia Guevara Alicia Chang-Cojulun José Brea-Del Castillo Melissa Palmieri Maria L. Avila-Agüero Francisco Javier Membrillo de Novales Carlos Torres-Martínez Sandra X. Olaya Sergio David Angulo Jaime A. Cardona-Ospina Roberto Debbag Carlos Espinal Maritza Cabrera Jaime David Acosta-España Darío S. López-Delgado Marco A. Solarte-Portilla Oscar Fraile Tatiana Drummond Rodrigo Nogueira Angerami Flor M. Muñoz Irene Benítez Kleber Luz María Alejandra López-Zambrano Cristina Hernán-García Daniel Leonardo Sánchez-Carmona Lisette Cortes Hernán Vargas Lysien Zambrano Danna Lucía Calderón-Medina Diana Alejandra Hernández-Ramírez Abraham Katime Álvaro A. Faccini-Martínez Leidy J. Medina-Lozano Beatriz Elena Porras-Pedroza Cristian Biscayart Ana Carvajal Lily M. Soto-Ávila Marbelys Hernández Rolando Ulloa-Gutierrez Laura Naranjo-Lara José Alejandro Mojica Matthew H. Collins Herberth Maldonado Marco A. P. Safadi Enrique Chacon-Cruz José A. Suárez

Yellow fever remains a major public health threat in endemic and re-emerging regions of Africa and South America, with recent outbreaks highlighting persistent gaps in prevention and surveillance. Pregnant women represent a particularly vulnerable population, yet the epidemiology, clinical impact, and preventive strategies for yellow fever in pregnancy are insufficiently characterized. Physiological and immunological changes during gestation may influence host responses to infection; however, current evidence does not demonstrate increased susceptibility to or severity of yellow fever during pregnancy. Adverse materno-fetal outcomes, including miscarriage, stillbirth, preterm birth, and, in rare cases, perinatal transmission, have been reported but remain poorly characterized. Diagnostic challenges, overlapping clinical presentations with other arboviral and hepatic diseases, and limited access to specialized care further complicate clinical management in many endemic settings. This perspective provides a comprehensive overview of yellow fever in pregnancy during the 2024–2026 outbreak in the Americas, including a risk-stratification framework for prevention. We summarize current evidence on epidemiology, pathophysiology, diagnosis, and supportive care, and examine prevention strategies with particular emphasis on vaccination. Accumulated observational evidence and substantial real-world experience have not demonstrated an increased risk of serious adverse events and generally support the effectiveness of yellow fever vaccination during pregnancy when administered with appropriate clinical judgment. In high-risk settings, the benefits of maternal immunization clearly outweigh theoretical concerns, supporting a flexible, risk-based approach, despite relatively limited evidence. We also discuss national and international policies, post-pregnancy booster recommendations, and the importance of integrating vaccination assessment into antenatal care. Finally, we highlight critical knowledge gaps and research priorities, including the need for prospective registries and strengthened pharmacovigilance. Coordinated clinical and public health strategies are essential to protect maternal and neonatal health and to reduce the burden of yellow fever in endemic and re-emerging settings.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11040091

Authors: Andrea Miján Oihane Martín Esther Ciancas Carmen Llorente Martín Gilechrist Lokoel Sarah Lokaala Daniel Lokiriama Sagrario de la Fuente Hernanz María Llorente de Santiago Ana Camila Bertomeu Jose A. Perez-Molina

Background: Schistosomiasis remains a significant neglected tropical disease in Kenya, but its presence in the western/northern Lake Turkana region is poorly characterised. We conducted an exploratory serosurvey to assess evidence of Schistosoma spp. exposure and a diagnostic accuracy study to evaluate dried blood spots (DBSs) for field serology. Methods: We performed a cross-sectional survey in adults (≥18 years) from six communities in the western/northern and shoreline area of Turkana Lake, excluding individuals with >6 months of residence in other Kenyan endemic areas. Capillary blood was collected on DBSs and tested centrally using ELISA for Schistosoma spp. IgG. In parallel, DBS cards performance was compared with paired routine serum ELISA in 23 patients assessed for suspected schistosomiasis at our centre. Results: We enrolled 155 participants (60% men; median age 30 years), with nearly universal reported freshwater contact (154/155, 99.4%). In the validation study, DBS values were lower than serum values (mean bias 0.27), with moderate correlation (r = 0.54) and modest discrimination (AUC 0.65; sensitivity 80% and specificity 50% at OD index >0.8). The median DBS ELISA OD index for the 155 participants was 0.55 (IQR, 0.34–0.79). Six samples exceeded 0.8, but these values were low, and all had negative IHA (<1/80), yielding no confirmed seropositive cases. Conclusions: These findings suggest low or absent sustained transmission in the sampled communities during the study period and indicate that DBS-based serology is operationally feasible but requires careful calibration and confirmatory testing for robust field inference.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11040090

Authors: Casimir Manzengo Farai Mavhunga Nlandu Roger Ngatu Fleur Lignenguet Stredice Manguinga Ghislaine Asseko Nkone

Although the estimated tuberculosis (TB) incidence in Gabon is declining, there have been challenges with treatment coverage, HIV status and treatment outcome documentation. Thus, the National TB Program (NTP) conducted an innovative data review at the Nkembo Health Treatment Center in Libreville, which manages more than 70% of Gabonese TB patients. Since our hypothesis was that the Nkembo treatment center was struggling with data mismanagement due to the workload, the objective was to perform a TB data quality review and triangulation exercise at the Nkembo health facility in Libreville, from January to August 2023, and propose recommendations for data improvement. Methods: The study used the data reconciliation method. This is a process that involves comparing and aligning data from multiple sources to ensure consistency, accuracy, and integrity. The primary purpose of data reconciliation is to identify and resolve discrepancies or differences between datasets and make them consistent. Using the “TB onion model”, analysis identified data mismanagement as a key contributor to underreporting. A data review compared TB records to TB registry data and patient folders from January to August 2023 for notification and to the 2022 cohort for treatment results. The study focused on notified TB cases, HIV status and TB treatment outcome documentation. Discrepancies were reconciled, and treatment outcomes re-evaluated. Results: After review, statistically significant increases were observed: +22% for total TB cases (p = 0.0003), +141% for the number of TB cases with known HIV status (p = 0.0017) and +104% for the number of TB cases successfully treated (p = 0.0001), as compared with the previous data. Discussion: This data reconciliation showed the usefulness of triangulation across data sources to improve the completeness of data. Also, current reported data underestimate the number of reported cases, documentation of HIV status, and treatment success. Conclusions: The study shows that data reconciliation can improve TB programmatic data completeness to better reflect program performance.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11040089

Authors: Nhung Pho Nguyen Nguyen Thuy Thi Nguyen Chonchadayu Phanpha Ketsarin Kamyingkird Adrian B. Hehl Tawin Inpankaew

Toxoplasma gondii and Neospora caninum are closely related apicomplexan parasites of veterinary and public health importance. T. gondii is a zoonotic pathogen for which cats are the definitive host, whereas N. caninum is a major cause of reproductive losses in cattle, with dogs acting as the definitive host. Data on exposure in pet animals in Thailand remain limited. This study investigated seroprevalence and associated risk factors of T. gondii and N. caninum in pet cats and dogs in Pathum Thani Province, an urban area adjacent to Bangkok. Between June 2020 and July 2021, serum samples were collected from 169 owned animals, including 86 cats and 83 dogs, participating in a mobile sterilization program. Antibodies were detected using the indirect fluorescent antibody test (IFAT), and animal characteristics, behaviors, and environmental factors were obtained via owner questionnaires. Serological evidence of exposure to both parasites was detected. Antibodies against T. gondii were detected in 4.73% (8/169) of animals, including 4.65% (4/86) of cats and 4.82% (4/83) of dogs. For N. caninum, the overall seroprevalence was 10.06% (17/169), with a higher prevalence in dogs (15.66%, 13/83) than in cats (4.65%, 4/86). No significant risk factors were identified for T. gondii or N. caninum infection in either cats or dogs (p > 0.05).

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11040088

Authors: Ariel Torres Gisselle Trujillo José Daniel Sánchez

Drug-resistant tuberculosis (DR-TB) represents a major public health threat, particularly in the prisons of Latin America and the Caribbean, where rates are up to 40 times higher than those observed in the general population. These facilities act as community amplifiers due to overcrowding, poor ventilation, diagnostic delays, and treatment discontinuity. This study offers a critical reflection on the magnitude, determinants, and implications of DR-TB in regional penitentiary contexts. A reflective analytical review was conducted in PubMed, Scopus, Web of Science, SciELO, and LILACS, complemented by WHO and PAHO reports, prioritising studies from 2019 to 2024. The findings reveal MDR-TB and pre-extensively drug-resistant (pre-XDR) outbreaks in Peru, Paraguay, and the Dominican Republic, as well as community transmission linked to prisons in Brazil and Colombia. Persistent gaps remain in systematic screening, drug susceptibility testing coverage, and post-release follow-up. Scientific production continues to be uneven and predominantly biomedical, with limited consideration of social and human rights determinants. DR-TB in prisons reflects the structural deficiencies of health and justice systems; its control requires intersectoral policies, genomic surveillance, and strategies that ensure early diagnosis, treatment continuity, and dignified detention conditions.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11040087

Authors: Sonia Menon Anthony D. Harries Riitta A. Dlodlo Gisèle Badoum Mohammed F. Dogo Olivia B. Mbitikon Pranay Sinha Yan Lin Jyoti Jaju Aung Naing Soe Anisha Singh Bharati Kalottee Kobto G. Koura

Background: Tuberculosis (TB) remains a major global health challenge, with Mycobacterium tuberculosis (M. tuberculosis) causing significant morbidity and mortality mainly in high-burden countries. Following exposure to M. tuberculosis, individuals may become infected, developing TB infection (TBI) through inhalation of the bacillus: this affects approximately one-fourth of the global population and serves as a critical reservoir for potential disease reactivation and transmission. The risk of being infected with M. tuberculosis is shaped by bacterial load of people with TB, contact patterns, environmental factors, and host susceptibility, particularly in high-risk congregate settings. Elucidating these determinants is instrumental for optimising TB prevention and control strategies. Methods: A preliminary PubMed search was conducted on 25 August 2024, using the keywords “latent tuberculosis infection,” “risk factors,” and “systematic review.” Targeted reviews were then performed in November 2024 to examine factors influencing progression from exposure to M. tuberculosis to TBI. Systematic reviews published between January 2000 and November 2024 were included. Results: The scoping review analysed eight systematic reviews, grouping findings into three key themes: (1) proximity and behavioural risk factors; (2) environmental risk factors; and (3) host immune vulnerabilities. Close contact with people with TB in crowded settings, such as dormitories, healthcare facilities, and prisons, was strongly associated with an elevated risk of TBI. Healthcare workers travelling from low- to high-incidence regions faced the highest risk due to frequent exposure to M. tuberculosis, while military personnel and general travellers had lower risks. Environmental exposures, including second-hand smoke and inadequate ventilation, further heightened susceptibility among children and adults. Host immune risk factors, such as advanced age, low body mass index, lack of BCG vaccination, and metabolic disorders such as diabetes, markedly increase susceptibility to TBI. The interplay between proximity, behavioural and environmental risk factors, and host immune vulnerabilities highlights the multifactorial nature of TBI risk. Conclusion: Effective TBI control demands a multifaceted approach, combining robust infection prevention and control measures, comorbidity management, and mitigation of behavioural risk factors like smoking. Tailored strategies are crucial for high-risk settings such as healthcare facilities and prisons. Multisectoral collaboration is essential to address key risk factors and protect vulnerable populations from progressing to TBI.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11040086

Authors: Achmad Naufal Azhari Agrin Zauyani Putri Ajib Diptyanusa Sunardi Sunardi Yayuk Agustin Hapsari Regina Tiolina Sidjabat Dauries Ariyanti Zainal Khoirudin Rezavitawanti Rezavitawanti Herdiana Herdiana Yullita Evarini Yuzwar Farida Alhosani

Schistosomiasis japonicum transmission in Indonesia has declined substantially over recent decades, placing it in the last miles of elimination in the Western Pacific Region. As programmes transition from control to interruption of transmission, surveillance systems must be capable of detecting residual transmission. This study synthesised routine epidemiological data from 2015 to 2025 to assess Indonesia’s readiness for elimination and to identify key surveillance gaps in near-elimination settings. Descriptive quantitative analysis was conducted using national surveillance data from two endemic districts in Central Sulawesi, complemented by programme reports on mass drug administration, human diagnosis, animal reservoir surveillance, and snail surveys. Results showed that while prevalence in humans has remained low and responsive to mass drug administration, transmission persists through infected animal reservoirs and intermediate snail hosts. Surveillance performance is constrained by limited diagnostic capacity, inconsistent snail survey coverage, fragmented paper-based reporting systems, and weak integration across human, animal, and environmental sectors. These findings indicated that low prevalence in humans alone is insufficient to demonstrate interruption of transmission, particularly in zoonotic schistosomiasis. In conclusion, Indonesia’s experience highlights the need to strengthen near-elimination surveillance through sensitive diagnostics, integrated One Health approaches, and digitally enabled data systems to sustain elimination and support future verification of schistosomiasis transmission interruption.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11030085

Authors: Özlem Kirişci Zerife Orhan

(1) Brucellosis is a zoonotic infection that remains a significant public health concern in endemic regions. This study aimed to determine the seroprevalence of brucellosis in a tertiary care hospital, analyze associated risk factors, and evaluate the diagnostic performance of commonly used serological tests. (2) The study was based on the serological test results of 24,545 samples collected between 2020 and 2023. Rose Bengal, standard tube agglutination, and Brucellacapt tests were used for the diagnosis of brucellosis. Data were analyzed according to age, sex, clinical department, and seasonal distribution using SPSS version 25.0. (3) Overall, 367 cases (1.5%) tested positive. When the 367 seropositive cases were evaluated by year, the annual distribution showed a declining trend, decreasing from 2.5% in 2020 to 1.2% in 2023. Among the positive cases, 57.8% were female, and 36% were aged between 41 and 64 years. The infectious diseases department had the highest positivity rate (37.1%). Brucellacapt showed the highest positivity rate (90.2%), followed by Rose Bengal (76.2%). The highest monthly positivity rate was observed in October (11.4%), and seasonally in autumn (31.3%). (4) The Brucellacapt test has demonstrated high sensitivity and serves as a valuable supplementary diagnostic tool in the evaluation of brucellosis. However, its low specificity underscores the necessity for careful interpretation of positive results and supports its use in conjunction with other serological tests to enhance diagnostic accuracy. Considering seasonal and departmental variations, a combined testing approach may improve overall diagnostic accuracy.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11030084

Authors: Victor Babawale Clement Adesigbin Corinne S. Merle Vanessa Veronese Fatimata Bintou Sall Benjamin Seydou Sombie Eunice Nnaisa Jiya-Chitumu Chizaram Onyeaghala Adegboyega Moses Oyefabi Rotimi Samuel Owolabi Osman Eltaye Olusoji Ige Ogiri Sam Obioma Akaniro Adebola Lawanson Victor Ombeka Muse Fadeyi

The introduction of significantly shorter, all-oral regimens has significantly shifted the management of drug-resistant tuberculosis (DR-TB) towards a more tolerable and patient-centred therapeutic approach that aims to enhance treatment adherence, clinical outcomes, and quality of life among patients. Nigeria has gradually adopted this all-oral, shorter regimen, but the impact of this regimen in programmatic settings has not yet been studied. In 2022, a longitudinal, two-armed cohort study was conducted to explore the effectiveness, safety, and feasibility of the all-oral shorter regimen in the programmatic management of RR/MDR-TB in Nigeria. Consenting and eligible RR/MDR-TB patients receiving the all-oral regimen (intervention group) in four states were consecutively enrolled and compared to those receiving the standard of care (SOC). Treatment effectiveness, proportion, and 95% confidence intervals of favourable and unfavourable outcomes were measured at the end of treatment and during follow-up (six and 12 months post-treatment). In total 383 Participants were followed monthly throughout the 9–12-month treatment phase and then reassessed at 6 and 12 months after treatment completion, giving a total possible observation period of up to 24 months (185 received the intervention and 198 the standard of care). At the end of follow-up, there was a higher but non-significant proportion of favourable outcomes among the intervention vs. SOC group (80% vs. 69.7%); a higher proportion of favourable outcomes was also noted at the end of treatment among intervention participants (81.1 vs. 76.8%). Around one third of patients reported at least one serious adverse event (SAE), with no significant differences between arms, and none were deemed related to the use of medication. Intervention participants reported greater improvements in health-related quality of life between baseline and four months compared to those receiving the SOC. These findings support the programmatic use of all-oral shorter treatment for RR/MDR-TB as a regimen that is effective, tolerable, safe, and associated with enhanced health-related quality of life for patients in Nigeria.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11030083

Authors: Romain Kibadi Lungoy Jean Ngoy Kitenge Nuccia Saleri Stephane Mbuyi Tshikunga Papy Pululu Emmanuelle Papot Corinne Simone Merle Anna Scardigli Jean Pierre Malemba Tshibuyi

The Democratic Republic of the Congo faces a high tuberculosis (TB) burden. In 2022, 61% of an estimated 402,000 TB cases were reported (World Health Organization Global tuberculosis report). To enhance case detection, the national TB program (NTP) introduced a program quality and efficiency approach (PQE), integrating systematic TB screening into outpatient departments (OPDs). Observational data of the PQE on the TB care cascade (from screening to treatment) across 70 sites in Kinshasa that initiated PQE during the first quarter of 2023 are presented. Data were collected monthly and validated during supervision visits, and disaggregated by sex, healthcare facility type (public, private, or faith-based), facility level (primary or secondary), and OPD within each facility. In 2024, 639,464 individuals were consulted in various OPDs in the participating facilities, 57% of which were female. The median number needed to screen (NNS) was 22.1, with an interquartile range of [9.5–104.3]. There was a significantly lower NNS observed in general practice and human immunodeficiency virus departments. Throughout the TB care cascade, women were less likely than men to be screened, tested, or treated. These findings, to be interpreted within the context of Kinshasa pilot facilities, provide insights to the NTP for developing PQE implementation research aimed at understanding the reasons for these discrepancies and informing NTP scale-up at the national level.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11030082

Authors: Shuangshuang Ma Qingling Wang Junjie Lin Yufeng Gao

Background: Acute hepatitis E (AHE) poses escalating risks to older adults (≥65 years), compounded by immunosenescence and comorbidities. Using Global Burden of Disease (GBD) 2021 data, this study analyzes global AHE burden, trends, and projections in aging populations. Methods: Age-standardized rates (ASIR, ASMR, ASDR) for AHE in adults ≥ 65 years were extracted from GBD 2021 across 204 countries (1990–2021). Frontier analysis assessed gaps between observed burdens and sociodemographic index (SDI)-based theoretical minima. Age-period-cohort (APC) modeling evaluated age/period/cohort effects. Bayesian (BAPC), NORDPRED, and ARIMA models projected trends to 2050. Results: Global ASIR increased by 1.5% annually (1990–2021), with ASMR and DALYs declining significantly. Middle SDI regions showed the steepest ASIR rise (net drift: 0.064%/year), while high SDI areas had volatile trends. Age effects peaked in ≥95-year-olds. Frontier analysis revealed persistent ASIR-SDI gaps, particularly in low-middle SDI regions. Projections indicate a ASIR rise by 2050 (113.04/100,000), contrasting with declining ASMR (0.056/100,000) and ASDR (1.31/100,000) and the NORDPRED, ARIMA, and EAPC models exhibit analogous global predictive trends. Conclusions: Diverging trends of rising incidence and falling mortality highlight unmet prevention needs. High-burden regions require SDI-stratified strategies, prioritizing vaccination programs (e.g., HEV 239), zoonotic transmission control, and enhanced surveillance. The Sustainable Development Goals (SDGs) envision hepatitis elimination by 2030 (Target 3.3). However, our analysis projects ongoing AHE burden in aging populations through 2050, indicating the need for post-2030 policy adaptations.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11030081

Authors: Pranav Shivashankar Praween Senanayake Thomas Stephen Ledger Nicholas Ngui

Background: Thyroid tuberculosis abscesses (TTA) are rare manifestations of extrapulmonary tuberculosis, with the available literature consisting almost exclusively of individual case reports and small observational series. This systematic review aimed to evaluate current management strategies and associated clinical outcomes for TTA. Methods: Reports describing confirmed TTA, specified treatment regimens and clinical outcomes were systematically identified and synthesised from PubMed, Embase, Web of Science and Google Scholar from the period 1990 to 2025. Studies with suspected but unconfirmed cases were excluded. Risk of bias was assessed using the Joanna Briggs Institute tool. A total of 22 studies comprising 33 patients were included. Results: Significant diagnostic delays were seen. When diagnosis was established, standard four-drug anti-tubercular therapy (ATT) for at least 6 months emerged as the predominant first-line treatment. Surgical or percutaneous drainage procedures were typically reserved for large abscesses, treatment failure, acute suppurative presentations or suspected malignancy. Across published cases, lesion resolution and preservation of euthyroid function were reported in 92% of patients. However, the absence of comparative studies and the reliance on highly selected case material limit definitive conclusions and raise concerns about publication bias. Conclusions: TTA is a rare entity, with established treatment success with ATT, with surgery reserved for selected cases. Higher-quality comparative data are required to inform optimal management strategies.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11030080

Authors: Ousmane Traore Toussaint Rouamba Serge Henri Zango Hermann Sorgho Innocent Valea Maminata Traore-Coulibaly Henk D. F. H. Schallig Halidou Tinto

In malaria-endemic regions, women remain vulnerable to Plasmodium falciparum infection at the time of delivery. However, the immunological mechanisms underlying infection-associated inflammation in primigravid women remain poorly characterized. This exploratory study investigated cytokine-based immune profiles reflecting malaria infection status at delivery. We assessed 33 primigravid women from Nanoro, Burkina Faso (mean age 19 years; range 18–20.5) at childbirth. Antibody responses to P. falciparum antigens (PfCSP, PfAMA-1, and EBA-175) and plasma levels of cytokines (IL-4, IL-10, IL-6, TNF-α, and IFN-γ) were quantified using enzyme immunoassays. Multivariate analyses, including principal component analysis (PCA) and hierarchical clustering, identified three distinct immune profiles: (1) a low-inflammatory cluster with reduced IL-6 and TNF-α, (2) a TNF-α–dominant cluster, and (3) a highly pro-inflammatory cluster with elevated IL-6 and TNF-α. Cluster stability was supported by bootstrap analysis (AU ≥ 92%). All women in the most inflammatory cluster were P. falciparum–positive at delivery (Fisher’s exact test, p = 0.04; exploratory association). These cytokine-driven profiles reflect biologically distinct inflammatory states associated with concurrent infection at delivery rather than predictive immune predispositions. The findings underscore the potential of cytokine profiling as a hypothesis-generating tool to guide future longitudinal studies on immune regulation and the postpartum period.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11030079

Authors: Davide T. Mosca Michela Martini

The convergence of climate change, migration, and health represents a critical global challenge, with the Middle East and North Africa (MENA) region illustrating acute vulnerabilities while offering insight relevant beyond the region. Increasing exposure to extreme heat, droughts, and floods drives displacement, constrained mobility, and adaptive migration, placing additional pressure on already stretched health systems. This paper proposes an integrated Nexus Action Framework for Climate Change, Migration, and Health (NAF-CMH) to address these interlinked dynamics and move beyond fragmented, sector-specific responses. The framework conceptualizes human mobility both as a potential resilience strategy and as a determinant of health, encompassing climate-affected migrants, displaced populations, and those experiencing involuntary immobility across diverse pathways and settings. It promotes systematic integration of health considerations into climate adaptation and migration governance and situates these interventions within the broader agenda of climate-resilient health systems. Drawing on a non-systematic narrative review of peer-reviewed and grey literature, complemented by the authors’ expertise, the paper identifies seven interrelated pillars for coordinated policy and operational action. While grounded in MENA-specific vulnerabilities, the framework is flexible and adaptable to other regions facing climate-driven mobility challenges. By providing an operational architecture for multisector collaboration, the NAF-CMH supports policymakers, public health authorities, and migration actors in strengthening resilience, reducing vulnerability and safeguarding health amid accelerating climate impacts and evolving mobility patterns.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11030078

Authors: Iván Mathias Alonso Paiva Florencia Muñoz González Cecilia Rotondaro Magali Bialer Paula Arias Arlinet Kierbel Mariana C. Ferrero Pablo C. Baldi

Brucella infection is frequently acquired by inhalation, but the pathogen disseminates systemically from the lungs. However, little is known about the interaction of Brucella spp. with the airways. Using a 3D air-exposed organotypic human bronchial tissue model (polarized 16HBE14o- bronchial epithelial cells grown over a collagen matrix containing MRC-5 lung fibroblasts), we analyzed Brucella abortus replication, translocation and cytokine responses over prolonged post-infection times. Apically inoculated B. abortus invaded, replicated and persisted during the whole follow-up (16 days) within the bronchial tissue without inducing cytotoxicity. Viable bacteria were also detected in the conditioned medium (CM) since day five post-infection, indicating release from the basolateral side. In parallel experiments, no invasion or bacterial release was detected for Escherichia coli. The levels of IL-6, IL-8 and MCP-1 were increased in CM from Brucella-infected 3D cultures and in monocultures of polarized bronchial epithelial cells or lung fibroblasts. Collagenase/gelatinase activity was increased in 3D cultures and MRC-5 monocultures. Infection transference from bronchial cells to lung fibroblasts was documented using monocultures. An immune cross-talk was detected, as cytokine levels were increased in fibroblasts stimulated with bronchial CM, and vice versa. These results suggest that the bronchial mucosa can sustain B. abortus persistence, replication and dissemination, and that it induces a proinflammatory response to which both epithelial cells and fibroblasts contribute.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11030077

Authors: Daniel Peñaherrera-Vásquez Alison Reina Gabriela Zambrano-Sánchez Maria Fernanda García-Aguilera German Fierro Silvia Jessica Guarderas-Muñoz Josue Rivadeneira Luis Fuenmayor-González

Background Expanded dengue syndrome represents a severe and atypical spectrum of dengue virus infection characterized by multisystem involvement beyond classic manifestations. While mild gastrointestinal symptoms are common in classic dengue, expanded dengue syndrome may present with clinically significant digestive organ involvement, including hepatitis, fulminant hepatic failure, pancreatitis, and acute acalculous cholecystitis. These manifestations often resemble primary gastrointestinal diseases, leading to diagnostic delays and inappropriate management. Despite increasing recognition, the true frequency of digestive system involvement remains poorly defined due to heterogeneous reporting and limited quantitative evidence. Methodology/Principal Findings A systematic review and meta-analysis was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and registered in the International Prospective Register of Systematic Reviews (PROSPERO; CRD420251270772). MEDLINE, Scopus, Web of Science, Embase, CENTRAL, Scielo, and BIREME were searched from inception to December 10, 2025. Primary studies reporting laboratory-confirmed dengue infection with atypical digestive system involvement and sufficient quantitative data were included. Seven studies comprising 1774 participants met eligibility criteria. Random-effects meta-analyses were performed to estimate pooled frequencies of gastrointestinal manifestations. The pooled frequency of hepatic involvement was 7% (95% confidence interval: 0–21), including fulminant hepatic failure (3%) and hepatitis (33%), with substantial heterogeneity. Acute pancreatitis occurred in 3% (95% confidence interval: 0–11) of cases. Acute acalculous cholecystitis was the most frequent manifestation, with a pooled frequency of 21% (95% confidence interval: 3–48). All included studies were classified as low risk of bias.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11030076

Authors: Andrea de Castro-Oliver Pedro Guevara-Hernández Javier Guillem Miquel Moret-Paredes Alicia Marco-Gabarre Alicia Lucas-Camps Celia Prades-Sirvent David Ruiz-Raga Ana Ventura Esteve Maria Amparo Perea Ribis Marina Llopis Sanchis Esther Izquierdo García Hamlet Ghukasyan María Pallás Cervera Carmen Visconti Martín Ana Isabel López Amorós Angie Gómez Uranga Sara Vela-Bernal Ana Isabel de Gracia-Leon Andreu Belmonte-Domingo Carolina Pinto-Pla Ana Ferrer-Ribera Anaïs Corma-Gómez María José Galindo María Rosa Oltra-Sempere Blanca Belizón María José Forner David Navarro Isabel Corrales Carlos Bea-Serrano

Strongyloidiasis is traditionally regarded as a tropical disease; however, in the Valencian Community (Spain), it has historically been linked to localized endemic foci considered of declining relevance. This was a multicenter regional case series study across three hospitals including patients ≥16 years with strongyloidiasis defined by positive serology and/or parasitological confirmation diagnosed from 2015 to 2024. A total of 301 patients were included (median age 53 years (quartile 1–quartile 3, 40–72); 135 (44.9%) female). Most cases were autochthonous (176/299, 58.9%), while 123/299 (41.1%) occurred in migrants, predominantly from Latin America. Symptoms were present in 165/296 (55.7%), most frequently cutaneous (68/296, 23.0%) and gastrointestinal (62/296, 20.9%). Eosinophilia (>500 cells/µL) was observed in 144/298 (48.3%) and severe infection (hyperinfection syndrome) in 7/294 (2.4%). Annual diagnoses increased over time, with a significant temporal trend by case origin (p < 0.001), reflecting an increasing contribution of imported infections, whereas trends by sex (p = 0.068) and immune status (p = 0.926) were not significant. Stool-based methods demonstrated a low diagnostic yield (microscopy 7/157, 4.5%; culture 21/136, 15.4%; rtPCR 2/27, 7.4%). These findings document the sustained detection of cases classified as autochthonous beyond historically recognized foci and an increasing proportion of imported diagnoses in a temperate European setting.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11030075

Authors: Galymzhan Ryskulov Malik Adenov Maira Zhaparkulova Alibek Bissembayev Gulnar Rakhimbekova Dariga Tanabayeva Shynar Tanabayeva Ildar Fakhradiyev Marat Shoranov

Background: Tuberculosis (TB) remains a major public health concern globally, despite sustained declines in incidence in many countries. Kazakhstan has implemented long-term national TB control strategies; however, comprehensive nationwide analyses integrating temporal trends, demographic patterns, and treatment outcomes over the past decade remain limited. Methods: A nationwide retrospective registry-based analysis of programmatic TB treatment episodes was conducted using anonymized data from the national tuberculosis registry of the Ministry of Health of Kazakhstan. All registered TB cases from 1 January 2014 to 31 December 2023 were included. Treatment outcome was analyzed as the final end-of-episode programmatic status (favorable vs. unfavorable). Because the anonymized extract did not contain complete patient-level dates required to derive person-time (treatment initiation and event dates), time-to-event models were not applied; instead, factors associated with unfavorable end-of-treatment outcomes were assessed using multivariable logistic regression and reported as adjusted odds ratios (aORs) with 95% CIs. Unfavorable treatment outcomes were defined as death, treatment failure, loss to follow-up, and not evaluated or not recorded outcome, according to the national TB program outcome definitions. Results: A total of 93,985 TB cases were analyzed. The number of registered cases declined from 16,391 in 2014 to 6548 in 2023, corresponding to a cumulative reduction of 60.1% and an AAPC of −9.7% per year. TB incidence decreased in both sexes, although rates remained consistently higher among men. Over time, the peak incidence shifted toward older age groups, particularly among men. The proportion of new cases increased to 80.1% by 2023, while relapses and treatment failures declined. In multivariable analysis, unfavorable treatment outcomes were independently associated with male sex (aOR 1.25), older age, relapse, treatment after interruption, prior treatment failure, smear-positive disease (aOR 1.60), combined pulmonary and extrapulmonary involvement, and disseminated TB (ICD-10 A19). The risk of unfavorable outcomes increased during 2020–2021 and declined in 2022–2023. Conclusions: Kazakhstan has achieved a substantial and sustained reduction in TB incidence over the past decade. Nevertheless, marked demographic and clinical disparities persist, particularly among men, older patients, smear-positive cases, and individuals with prior or interrupted treatment. Targeted interventions focused on these high-risk groups may further improve treatment outcomes and support continued progress toward TB control.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11030074

Authors: Luis Eduardo Del Moral Trinidad Gilberto Silva Bañuelos Esteban Gonzalez-Diaz Melva Guadalupe Herrera Godina

In the published publication [...]

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11030073

Authors: Md. Abu Bokkor Shiddik Farzana Zannat Toshi Sadia Yesmin Md. Siddikur Rahman

Dengue is a mosquito-borne viral disease which is predominantly endemic in tropical and subtropical countries. In Bangladesh, 321,179 dengue cases were reported in 2023, followed by 101,214 cases in 2024, which highlights a severe and ongoing public health challenge. Dengue transmission risks are shaped by climatic variability, rapid urbanization, socio-economic vulnerability, and healthcare strain. But existing dengue surveillance models remain limited in their ability to capture district-level disparities in Bangladesh. This study aimed to develop a district-level dengue early warning system that integrates climatic, socio-demographic, economic, healthcare, and environmental determinants to generate accurate and interpretable predictions. We examined dengue cases across all 64 districts in Bangladesh from 2017 to 2024, integrating Directorate General of Health Services (DGHS) case records with climate, socio-demographic, economic, and healthcare indicators. Machine learning and deep learning approaches, including Multi-Layer Perceptron (MLP) and Convolutional Long Short-Term Memory (ConvLSTM), were combined with SHAP (Shapley Additive Explanations)-based explainable artificial intelligence. We also used Bayesian spatio-temporal models to capture spatial clustering, temporal dependence, and the lagged transmission effects of dengue. Dengue outbreaks peaked in September 2023, with Dhaka recording 113,233 cases. DENV-4 (Dengue Virus type 4) emerged in 2022, accounting for 27% of infections in 2023. Climate was the strongest predictor of dengue transmission (humidity SHAP = 0.314; minimum temperature SHAP = 0.146; rainfall RR = 1.303). Poverty (SHAP = 0.193) and healthcare capacity (nursing/midwifery density SHAP = 0.073) mostly contributed to dengue prediction. The MLP model achieved the best yearly performance (accuracy = 0.93; ROC-AUC = 0.99), ConvLSTM was the best model in monthly prediction (recall = 0.88; ROC-AUC = 0.81), and Bayesian BYM2_RW2 with lagged effects improved predictive fit (DIC = 3671.055). Our integrated framework delivers transparent, interpretable predictions and district-level early warnings, supporting adaptive dengue outbreak preparedness and resource allocation in Bangladesh.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11030072

Authors: Menghua Yu Xinyue Liu Na Shi Jiaqi Su Lefei Han Jian He Yaoqian Wang Suying Guo Wangping Deng Chao Lv Lijuan Zhang Bo Fu Hanhui Hu Jing Xu Xiao-Nong Zhou Xiaoxi Zhang

Schistosomiasis elimination is increasingly constrained less by the technical efficacy of single interventions than by systemic dynamics in coupled human–animal–environment settings, including nonlinear feedback, spatial heterogeneity, and cross-sectoral govern frictions. We conducted a systematic methodological review (search date: 1 January 2026) across PubMed, Web of Science, Scopus, EconLit, and CNKI to identify studies that (i) addressed schistosomiasis control, (ii) used explicit system-based, causal, or network-oriented analytical structures, and (iii) incorporated economic evaluation with multi-domain outcomes. We synthesized modeling architectures, economic methods, and approaches to trade-offs and uncertainty, and applied an evidence-informed systemic causality framework to assess decision-analytic adequacy. The literature grouped into three related strands: transmission and system dynamics models that capture feedback processes and rebound risks; economic evaluations dominated by cost-effectiveness analyses; and cross-sectoral or surveillance-oriented decision models optimizing implementation under resource constraints. Across strands, elimination-stage investments such as surveillance, environmental management, and coordination exhibit strong externalities and quasi-public-good properties that are systematically undervalued in single-sector, single-metric frameworks. We argue that decision-relevant evaluation should be reframed as a multi-objective resource allocation problem that integrates systemic modeling with economic valuation, explicitly addresses uncertainty, and applies multi-criteria decision analysis to support long-horizon, cross-sectoral decision-making.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11030071

Authors: Melis Deniz İsa An Kerim Parlak Hasan Tezer

Objective: We aimed to describe the clinical features and treatment outcomes of pediatric patients with leishmaniasis. Methods: This retrospective study included pediatric patients (>1 month–18 years) diagnosed with leishmaniasis at Şanlıurfa Training and Research Hospital between January 2022 and January 2024, identified from electronic medical records. Results: Among patients with cutaneous leishmaniasis, fifty pediatric patients were evaluated. Plaques (n = 34, 68%) and ulcerative lesions (n = 8, 16%) were the most common lesion types, with the face and neck being the most frequently affected sites (n = 34, 68%). The number of previously used antibiotics was statistically significantly higher in the multiple-lesion group compared to the single-lesion group (p = 0.022). Conclusions: Clinicians should consider cutaneous leishmaniasis in children with plaque or ulcerative skin lesions and a history of travel to an endemic area. Early detection and timely treatment can prevent long-term damage and cosmetic issues, leading to improved patient outcomes.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11030070

Authors: Beatriz Amparo Rodríguez-Olguin Daniel F. Lozano Beltrán Isabel Mariscal Sejas Brandon N. Mercado-Saavedra

Chagas disease remains a major public health concern in Latin America, with Bolivia reporting one of the highest burdens of infection. While congenital transmission has become the predominant route of new infections in several countries, vector-borne transmission persists in rural and peri-urban regions. Postrervalle, in the department of Santa Cruz, is officially classified as a low-infestation area; however, updated community-level data remain limited. We conducted a cross-sectional study in July 2023 involving 58 mothers and 104 of their children in Postrervalle. Participants underwent serological screening with three diagnostic assays, and epidemiological data were collected via structured maternal questionnaires. Logistic regression models were used to assess associations between child Trypanosoma cruzi seropositivity and maternal or household exposures during pregnancy. Seroprevalence was 15.5% among mothers and 3.8% among children. Notably, all seropositive children were born to mothers who tested seronegative, suggesting non-congenital transmission. In multivariable analysis, living in houses with mud walls during pregnancy was strongly associated with child seropositivity (adjusted OR = 38.566), while older child age also increased the odds of infection. Other maternal exposure variables showed elevated but imprecise associations. Despite its classification as a low-infestation area, Postrervalle shows serological patterns consistent with postnatal acquisition linked to domestic structural conditions that facilitate triatomine colonization. These findings overall highlight the need for integrated serological and entomological surveillance to better characterize and prevent Chagas transmission in rural communities.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11030069

Authors: Joanna Ina G. Manalo Adeliza Mae L. Realingo Lei Lanna M. Dancel Timothy John R. Dizon Amalea Dulcene Nicolasora Kristine Alvarado-Dela Cruz Desiree D. Argana Arjay Niño A. Digman Emarld Julian G. Medina Celine Bernice A. Roxas Rubelia A. Baterna Julieta Z. Dungca

Leptospirosis remains a public health concern in the Philippines. Conventional diagnostic methods, including the microscopic agglutination test (MAT) and qPCR, are routinely used for outbreak response and surveillance. However, these methods often yield discordant results due to cross-reactivity, limited sensitivity, or lack of species-level resolution. To address these diagnostic gaps, this study optimized the Boonsilp 16S rRNA PCR assay and applied Sanger sequencing for accurate species identification of Leptospira in 92 archived DNA samples collected between 2018 and 2020. The sensitivity and specificity of the optimized assay were compared with those of MAT and qPCR. Species-level identification was confirmed via sequencing, and a phylogenetic tree was constructed. Among the 92 samples, 46 (50.0%) tested positive by qPCR, 39 (42.4%) by MAT, and 67 (72.8%) by at least one of the two methods. The optimized Boonsilp assay detected Leptospira in 23 samples (25.0%), of which 22 were also qPCR positive. Twenty-one samples were confirmed as L. interrogans, one as L. borgpetersenii, and one as an unclassified Leptospira species. One sample undetected by both MAT and qPCR tested positive using the optimized assay. Compared to the composite reference, the Boonsilp assay showed 32.8% sensitivity and 96.0% specificity. Phylogenetic analysis revealed multiple L. interrogans strains, including those closely related to reference sequences of Copenhageni, Manilae, and Canicola. While the optimized Boonsilp PCR assay demonstrates diagnostic value as an adjunct molecular tool to qPCR and MAT supporting species-level identification during outbreak surveillance, this warrants further validation in freshly isolated DNA samples.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11030068

Authors: José Henrique Francisco Roma Rachel Cruz Alves Bruno Moreira Carneiro Renata Dezengrini Slhessarenko Juliana Helena Chavez-Pavoni Mariângela Ribeiro Resende

In countries where Dengue virus is endemic, the occurrence of outbreaks and epidemic events is strongly associated with viral genomic evolution. In addition, the introduction of a new agent, such as Zika virus, in a naive population and its concomitant circulation may increase mutations and virulence. This study aimed to characterize the molecular patterns and circulation of Zika and Dengue viruses inland of midwestern Brazil. Samples from reported cases of zika and dengue fever were subjected to molecular and phylogenetic analyses. Partial genomes of these viruses were recovered and characterized from six samples. Phylogenetic analysis revealed that the Zika virus clustered within the American strain of Asian/American lineage and Dengue virus grouped within the Brazilian lineage (BR04) of serotype 2 from the Asian/American genotype. Amino acid substitutions, and consequently nonsynonymous mutations, were identified in the RdRp domain of the NS5 protein coding region in the recovered genomes from both viruses. These findings highlight the importance of molecular epidemiological surveillance, especially in endemic regions with cocirculation and substantial epidemic risk. Ongoing monitoring efforts are crucial to better understand viral evolution and its potential impact on future outbreaks and epidemic dynamics.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11030067

Authors: Pontus Westerström Joanna Malgorzata Bivand Øyvind Kommedal Birgitta Ehrnström Joakim Stray Andreassen Jan Egil Afset

Background: Recent diagnostic methods have enabled the detection of often culture-negative pathogens, including anaerobic bacteria from the oral cavity. Characterising the microbial diversity and co-occurrence of bacteria in such infections is important for understanding the molecular pathophysiology in odontogenic brain abscesses. Case presentation: We describe a case of polymicrobial odontogenic brain abscess in a 59-year-old man of Vietnamese ethnicity with a documented increased risk of brain abscess due to Hereditary Haemorrhagic Telangiectasia (HHT). The microbiological diagnostic work-up included conventional culture, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), targeted 16S rDNA analysis using three broad-range group-specific PCR (polymerase chain reaction) assays and next-generation sequencing (NGS). A literature review was conducted, including database searches for each identified microorganism. Twelve anaerobic bacterial species were detected, among which Treponema medium, Capnocytophaga HMT-323 and Candidatus Saccharibacteria oral taxon 488 have not previously been reported in brain abscesses. In addition, we identified the extremely rare pathogens Arachnia propionica and Capnocytophaga ochracea. Conclusion: This is the first report of Ca. Saccharibacteria oral taxon 488 in a clinical sample and the first detection of any species from this phylum in a brain abscess, co-detected with A. propionica, consistent with its obligate epibiotic lifestyle. Our findings broaden the known microbial diversity associated with odontogenic brain abscesses and underscore the value of 16S rDNA NGS in characterising polymicrobial infections, particularly when fastidious or uncultivable organisms are involved.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11030066

Authors: Kyra Thompson Scott Lyons Katherine Malone Jesse Fryk Alyssa Pyke Kate Murton

During the 2024/2025 wet season, Townsville had its first sustained autochthonous outbreak of dengue disease caused by dengue virus type 2 (DENV-2), the second locally transmitted outbreak of dengue since 2014 following the introduction of wMel strain Wolbachia-infected mosquitoes, a control strategy for dengue virus (DENV) and other Aedes-transmitted arboviruses. In comparison to two recorded locally acquired cases of dengue in 2020, the 2024/2025 outbreak resulted in sixteen cases in two inner-city suburbs of Townsville during the wet season associated with higher-than-average rainfall. This second dengue outbreak since 2014 highlights that Townsville and other north Queensland communities where Wolbachia mosquito programs have been deployed remain vulnerable to DENV incursions and local disease outbreaks despite the apparent high coverage of Wolbachia-infected mosquitoes. Whilst these control strategies have likely contributed to a reduction in the number and frequency of autochthonous DENV outbreaks in north Queensland, ongoing maintenance and monitoring of Wolbachia-infected mosquito coverage is necessary, together with timely review and improvement in dengue awareness and prevention health promotion activities in the community.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11030065

Authors: Jeanny Fernanda Chapuz-Magaña Nina Mendez-Dominguez Karla Dzul-Rosado Edgar Villarreal-Jimenez Amonario Olivera-Mar Vida Merry Salazar-Tostado Miguel Santaularia-Tomas

Background: Rickettsial diseases are endemic in southeastern Mexico, yet their potential subclinical cardiac effects remain poorly understood. Although severe spotted fever and typhus group infections may cause myocarditis and arrhythmias, limited evidence exists regarding cardiac alterations in individuals previously diagnosed with rickettsiosis who later show Rickettsia spp. IgG seropositivity. Methods: This follow-up observational study was conducted at a tertiary referral hospital in the Yucatan Peninsula. From an initial cohort of 390 patients evaluated for suspected rickettsial disease, 284 were confirmed as IgG-positive during follow-up. Among them, 18 adults who were asymptomatic for acute rickettsiosis at reassessment, but reported mild or nonspecific cardiac symptoms, underwent standardized cardiological evaluation. Procedures included a 12-lead electrocardiogram (ECG), transthoracic echocardiography, and 24 h Holter monitoring. All studies were reviewed independently by two blinded cardiologists with senior adjudication. Results: Global systolic function was preserved in all participants. However, subclinical abnormalities were identified, including right ventricular dilation in 16.7%, clinically relevant QTc prolongation in 22.2%, sinus pauses in 11.1%, reduced heart rate variability in 11.1%, atrial flutter in one patient, and complete left bundle branch block in one patient. QTc prolongation was detected exclusively through Holter monitoring. Conclusions: Adults previously diagnosed with rickettsiosis may exhibit subclinical cardiac involvement despite apparent recovery. Holter monitoring appears more sensitive than ECG for identifying electrical disturbances, warranting larger prospective studies.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11030064

Authors: Alicia X. Y. Ang Po Ying Chia Penny Oh

Dengue remains a public health concern in Singapore, with endemic transmission and recurring outbreaks. This study presents results from a Singapore-focused subgroup of the Growth and Emerging Markets Knowledge, Attitudes, and Practices (GEMKAP) cross-sectional survey, which assessed public Knowledge, Attitudes, and Practices (KAP) levels related to dengue and prevention. A total of 400 adult respondents from Singapore participated in an online survey conducted between September and October 2022. Overall KAP scores were 48% (Knowledge), 61% (Attitudes), and 36% (Practices). Awareness of dengue transmission was widespread (96% identified mosquitoes as the vector and 97% recognised stagnant water breeding), while fewer respondents recognised the availability of a dengue vaccine (23%) or the absence of a medicinal cure (38%). Trust in the government’s dengue control efforts was high, though respondents practised an average of 5.1 out of 10 recommended prevention measures. Of the respondents, 25% had a high willingness to vaccinate against dengue. Multivariate analysis revealed that positive vaccine perceptions, past dengue experience, automatic motivation, and social opportunity were associated with willingness to vaccinate. Respondents supported a multi-pronged dengue management approach combining education, vector control, and vaccination. Future efforts should integrate behaviour change strategies, enhance multi-stakeholder collaboration, and empower communities to ensure sustainable impact.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11030063

Authors: Prince Kyere Dwaah Nana Yaa Awua-Boateng Sylvia Afriyie Squire Ernest Osei David Kando Rogermilla Enam Dunu Daniel Nartey Helen Djang-Fordjour Patience Edze

Rabies remains a zoonotic public health problem in Ghana despite the availability of effective preventive measures, including mass dog vaccination and timely post-exposure prophylaxis (PEP). We conducted a community-based cross-sectional mixed-methods study between June and December 2025 to assess rabies-related knowledge, risk perception, health-seeking behaviour following dog bites, and dog vaccination practices within a One Health framework. Structured face-to-face interviews were conducted with 450 adults from selected urban and rural communities in the Greater Accra, Ashanti, and Bono East regions, supplemented by focus group discussions. Quantitative data were analysed using descriptive statistics, chi-square tests, and multivariable logistic regression. Overall, 68% of respondents had heard of rabies; however, detailed knowledge of transmission and prevention was limited, with 189 (42.0%) correctly identifying dogs as the main source of transmission. Following suspected exposure, 162 (36.0%) reported using home remedies or traditional treatments. Dog vaccination coverage was 31.1%, below the level required to interrupt transmission. Educational level, place of residence, and prior dog-bite exposure were significantly associated with rabies knowledge, health-seeking behaviour, and vaccination practices (p < 0.05). This study provides updated evidence on community rabies knowledge, risk perception, and preventive practices, highlighting behavioural and structural gaps that may hinder effective control in Ghana.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11020062

Authors: Adam T. Craig Clement Couteaux Ken Jetton Roger Nehemia Oliver Sokana Tanebu Tong Temea Bauro Taulanga Baratio Ofa Tukai Joe Takai Satupaitea Viali Noel Gama Soares Maria Ome-Kaius Mary Yohogu Litiana Volavola Patricia Tatui Fasihah Taleo Salanieta Saketa Andie Tucker Charles Mackenzie Katherine Gass Holly Jian Colleen L. Lau Harriet L. S. Lawford

Lymphatic filariasis (LF) is a mosquito-borne neglected tropical disease that causes substantial morbidity and social exclusion. Global efforts under the World Health Organization’s Global Programme to Eliminate Lymphatic Filariasis have markedly reduced prevalence, and several Pacific Island Countries and Territories (PICTs) have achieved elimination of the disease as a public health problem. However, post-validation surveillance (PVS), essential for detecting resurgence and enabling early response, has rarely been implemented, and barriers to its delivery remain poorly understood. We used two complementary qualitative approaches to identify systemic barriers and enablers to LF PVS in PICTs. First, we conducted a Nominal Group Technique followed by a structured expert elicitation involving program managers and technical staff. Data were analysed thematically and triangulated across sources. Participants identified 70 challenges which were consolidated into ten thematic domains. Pertinent barriers relate to limited leadership understanding of LF and surveillance options, inconsistent technical and financial support, and a lack of context-appropriate operational guidance. Additional challenges included limited field-ready diagnostics, procurement delays, the absence of formal mandates, and low community engagement. Enablers included embedding PVS within existing health services, leveraging trusted community networks, strengthening regional frameworks, and co-developing practical tools with countries. Sustaining LF elimination in the Pacific will require political commitment, regional collaboration, and integrated, programmatic approaches informed by recent PVS experience.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11020061

Authors: Beatriz Rodríguez-Alonso Hugo Almeida Montserrat Alonso-Sardón Inmaculada Izquierdo Ángela Romero-Alegría Amparo López-Bernús Virginia Velasco-Tirado Josué Pendones Ulerio Javier Pardo Lledías Moncef Belhassen-García

Nationwide hospital discharge databases are increasingly used in infectious disease research, yet their methodological strengths and limitations are rarely synthesised. In Spain, the Minimum Basic Data Set (Conjunto Mínimo Básico de Datos, CMBD) was implemented in 1987 and provides near-universal coverage of acute-care hospitalisations and has been widely applied in infectious disease epidemiology. However, its overall contribution and intrinsic constraints have not been comprehensively mapped. Given the breadth of infections, study designs, populations and outcome definitions in CMBD-based research, effect-size synthesis was not feasible; therefore, we conducted a scoping review with an evidence-mapping approach. We aimed to synthesise the scope, applications and methodological limitations of CMBD-based infectious disease research since its implementation. We conducted a scoping review following JBI guidance and reported according to PRISMA-ScR. PubMed, Embase, Web of Science and Scopus were searched from inception to 25 November 2024 for peer-reviewed journal articles in English or Spanish using CMBD data to investigate infectious diseases in Spain (no restrictions were applied by study design; grey literature was excluded). Screening, data charting and synthesis were completed during 2025. Four reviewers independently screened records and charted data. Studies were classified by infectious disease focus, syndromic category, study design and geographical scope. A total of 359 studies published between 1996 and 2024 were included, mostly retrospective observational analyses. Infectious diseases were the primary focus in 225 studies (62.7%), most commonly respiratory, gastrointestinal/liver and vaccine-preventable infections. Subnational analyses were concentrated in a limited number of regions. Over 80% of reported limitations reflected intrinsic CMBD features. Over three decades, the CMBD has become a cornerstone of hospital-based infectious disease research in Spain, enabling robust national analyses. However, limitations in clinical detail, microbiological confirmation and coding consistency constrain aetiological specificity and causal inference, highlighting the need for data validation and linkage with complementary sources.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11020060

Authors: Jennifer Rossouw Hermanus D. W. Geyer Monica Birkhead Douglas Wilson Jeremy Nel Alan S. Karstaedt Carel E. Haumann Annelize Jonker Jason W. Sahl David M. Wagner John A. Frean

Melioidosis is increasingly recognised in tropical and subtropical regions worldwide as a serious and potentially fatal bacterial infection affecting humans and animals, acquired from the environment. Until now, human cases of melioidosis had not been reported in Southern Africa. Over a four-year period, we identified three human and two animal cases of melioidosis in South Africa and Namibia. Burkholderia pseudomallei isolates were investigated by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) and whole-genome sequencing (WGS). Phylogenetic analysis demonstrated substantial diversity, suggesting long-term cryptic persistence of the bacterium in the Southern African region. Limited awareness of the disease and inadequate diagnostic capacity likely contribute to its apparent rarity in the region. These findings underscore the urgent need for increased surveillance, improved diagnostics, and greater awareness of melioidosis in Southern Africa to better understand its true epidemiological burden and prevent future cases.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11020059

Authors: Mario J. Olivera Adriana Arévalo Alejandro Marcel Hasslocher-Moreno

Clinical trajectories following Trypanosoma cruzi infection are heterogeneous, and the determinants of post-treatment parasitological dynamics and cardiac progression remain incompletely characterized, particularly in TcI-predominant regions. This study assessed, in both the acute phase and the indeterminate chronic form, the association between TcI infection and molecular clearance kinetics, cardiac progression, and the prognostic value of early molecular response. An ambispective cohort in Colombia included patients with acute or indeterminate chronic infection followed between 2000 and 2023. Sustained clearance was defined as two consecutive negative quantitative polymerase chain reaction results obtained at separate visits. Time-to-event analyses were conducted using Kaplan–Meier curves and Cox proportional hazards models. TcI infection was consistently associated with delayed molecular clearance in both clinical presentations. Although long-term clearance was achieved in most patients, TcI infection was independently associated with a higher risk of cardiac progression. In contrast, quantitative polymerase chain reaction negativity at 12 months was associated with reduced subsequent progression risk, indicating that sustained molecular response is a clinically meaningful prognostic marker. Collectively, these findings support the incorporation of early molecular monitoring into risk-stratified follow-up strategies in TcI-predominant settings and reinforce the need for phase-specific clinical management approaches.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11020058

Authors: Sonia Menon Anthony Harries Riitta Dlodlo Gisèle Badoum Mohammed Dogo Olivia Mbitikon Pranay Sinha Yan Lin Jyoti Jaju Aung Soe Anisha Singh Bharati Kalottee Kobto Koura

Background: Tuberculosis (TB) remains a major global health challenge, with transmission influenced by the incidence of contagious people with TB, the duration of infectivity, and the probability of contact with susceptible individuals. This review synthesizes recent evidence on established and emerging risk factors influencing TB transmission, particularly in light of global trends such as migration, urbanization, and demographic shifts, to guide future prevention and control strategies. This scoping review maps and synthesizes evidence from systematic reviews on risk factors for Mycobacterium tuberculosis exposure. Methods: A preliminary general literature search was conducted in PubMed on 25 August 2024, using the keywords “tuberculosis,” “risk factors,” and “systematic review.” A subsequent targeted search focused on systematic reviews published since 2000 that examined social and environmental determinants of exposure to M. tuberculosis identified in the general search. Original research and reviews spanning pre-2000 were excluded. Data extraction and synthesis followed PRISMA-ScR guidelines. Results: Of the 344 systematic reviews identified, 14 met the eligibility criteria, reporting on key risk factors contributing to the incidence of contagious people with TB, the duration of infectivity, and the probability of contact. These risk factors included homelessness, migration, occupational exposure, urbanization, climate change, and air pollution. The findings emphasize the complex interrelated role of social and environmental determinants in driving TB transmission. Conclusion: This review highlights the need for a multi-sectoral approach to TB, as climate change, air pollution, overcrowding, stigma, and limited healthcare access exacerbate established risks related to poverty. Effective prevention and control require targeted interventions that address these interconnected factors.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11020057

Authors: Luis Del Moral Trinidad Gilberto Silva Bañuelos Esteban Gonzalez-Diaz Melva Herrera Godina

Tuberculosis (TB) remains a persistent public health challenge in Mexico, particularly in large urban settings marked by social heterogeneity. We conducted a retrospective cohort study of patients diagnosed with tuberculosis and treated at a tertiary-level hospital in Guadalajara, Mexico, between 2020 and 2023. Unfavorable treatment outcomes were defined as treatment failure, loss to follow-up, or death. Multivariable logistic regression was used to identify factors independently associated with unfavorable outcomes. Spatial analyses, including Kernel Density Estimation, Global Moran’s I, Local Indicators of Spatial Association (LISA), and Getis–Ord Gi*, were applied to explore the geographic distribution of unfavorable outcomes. Unfavorable tuberculosis treatment outcomes among patients treated at a tertiary-level hospital were not randomly distributed in space. Spatial epidemiological methods provided complementary, exploratory insights beyond individual-level clinical factors, highlighting geographic patterns that may inform place-sensitive public health interventions and strengthen routine tuberculosis surveillance, without implying causal inference.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11020056

Authors: Ledile Francina Malebana Maasago Mercy Sepadi Matlou Ingrid Mokgobu

Communicable diseases remain a significant public health burden in South Africa, particularly where environmental determinants of health intersect with fragmented surveillance systems. Environmental Health Practitioners (EHPs) are legally mandated to implement the surveillance and prevention of communicable disease services at the municipal level. However, this function is inconsistently operationalised and often remains reactive (outbreak-driven), with limited integration into broader national surveillance systems. This study protocol outlines a mixed-methods investigation to develop a practical framework to strengthen the communicable disease surveillance and prevention function within Environmental Health Services in South Africa. The study will assess existing guiding tools, operational practices, and intersectoral collaboration mechanisms supporting surveillance across metropolitan and district municipalities. Quantitative data will be collected through a national survey of EHPs, while qualitative data will be generated through key informant interviews with national stakeholders, focus group discussions with municipal health managers, and a targeted review of municipal documents. Quantitative data will be analysed using descriptive and inferential statistics, while qualitative data will be thematically analysed and triangulated across data sources. The expected outcome is an integrated framework that clarifies roles, strengthens data flow, and promotes proactive, coordinated surveillance and prevention of communicable diseases within environmental health. The developed framework is anticipated to inform policy discussions and may contribute to efforts aligned with Sustainable Development Goal 3, Target 3.3, on reducing communicable disease burdens, by strengthening municipal communicable disease surveillance and prevention.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11020055

Authors: Ebtisam Bakhsh Rasha Doumi Najd Alqahtani Shahad Althubiti Jana Hagr Abeer Alnujide Shouq Alobaid Jana Allaboon Shatha Alotaibi Duaa Aljuhaymi Maha Alotaibi Abdullah Assiri

Rabies remains a fatal yet preventable zoonotic disease, and understanding population-level knowledge, attitudes, and practices (KAP) is essential to guide national elimination strategies. This nationwide cross-sectional study assessed rabies-related KAP among 2116 residents across all major regions of Saudi Arabia. An online validated questionnaire measured sociodemographic characteristics and KAP indicators. Descriptive and inferential statistics, including logistic regression, were used to identify predictors of good KAP outcomes. Overall, more than half of participants demonstrated poor knowledge (54.9%), particularly regarding rabies etiology, transmission, and essential post-exposure wound care, while attitudes toward prevention were overwhelmingly positive (92%). Despite this, several unsafe practices persisted, including interaction with stray animals and use of traditional remedies. Good knowledge was significantly associated with higher income, pet ownership, and residency in the Central region, whereas younger age and Northern residency predicted poorer practices. Mediation analysis suggested that knowledge may partly explain (mediate) the association between sociodemographic characteristics and reported preventive practices; however, causal inference is limited by the cross-sectional design. These findings demonstrate substantial knowledge and behavioral gaps despite favorable attitudes and highlight the need for culturally tailored educational interventions, improved access to post-exposure prophylaxis, and strengthened One Health strategies to support rabies elimination in Saudi Arabia.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11020054

Authors: Adam T. Craig Harriet L. S. Lawford Temea Bauro Clement Couteaux Litiana Volavala Myrielle Dupont-Rouzeyrol Noel Gama Soares Roger Nehemia Maria Ome-Kaius Prudence Rymill Fasihah Taleo Patricia Tatui ‘Ofa Sanft Tukia Satupaitea Viali Mary Yohogu Fiona Angrisano Leanne J. Robinson Salanieta Saketa Andie Tucker Charles Mackenzie Susana Vaz Nery Venkatachalam Udhayakumar Katherine Gass Patrick Lammie Colleen L. Lau

Lymphatic filariasis (LF) is a mosquito-borne neglected tropical disease targeted by the World Health Organization (WHO) for global elimination as a public health problem. Sixteen Pacific Island countries and territories were historically endemic, and eight have now met the WHO criteria for elimination as a public health problem. Elimination as a public health problem does not imply zero transmission. Rather, it denotes that LF prevalence has been reduced below a defined threshold at which community transmission can be sustained. Following validation of elimination, the WHO recommends post-validation surveillance (PVS) to detect potential re-emergence of LF as a public health problem. However, implementing PVS is challenging in Small Island Developing States with dispersed populations, limited workforce capacity, resource constraints, and competing health priorities. The ‘Voices and Visions: Building Partnerships for Integrated Serosurveillance of LF and Other Infectious Diseases in the Pacific Islands’ meeting was held in Brisbane, Australia, from 8–10 July 2025. Fifty-one delegates, including Pacific LF programme managers, WHO representatives, global health partners, and academic researchers, reviewed regional PVS progress, discussed the newly released WHO guidelines for the implementation, monitoring, and evaluation of PVS, planned for PVS implementation, and explored novel multiplex bead assay (MBA) serological analysis methods to strengthen regional coordination for its development as a public health tool. Five broad themes emerged. First, the new WHO Monitoring and Epidemiological Assessment of Mass Drug Administration in the Global Programme to Eliminate Lymphatic Filariasis: A Manual for National Elimination Programmes, 2nd edn needs to be operationalised to meet decision-making needs across diverse Pacific settings. Second, integrating LF-PVS with existing surveys and health service activities could improve efficiency and long-term sustainability. Third, regional coordination and alignment of funding cycles will require high-level collaboration. Fourth, community engagement is essential to strengthen demand for PVS. Finally, while at an early stage and with further evidence needed, MBA laboratory methods hold promise for cost-effective, feasible integrated multi-pathogen serosurveillance.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11020053

Authors: Méryl Delrieu Olivia O’Connor Nicolas Pocquet Kenny Teraiharoa Anne-Fleur Griffon Christophe Menkes Morgan Mangeas Elvina Viennet Valérie Burtet-Sarramegna Myrielle Dupont-Rouzeyrol Francesca D. Frentiu

Dengue virus (DENV) is a major public health concern in tropical and subtropical regions, including the Pacific. Temperature is recognised as a major driver of transmission under climate change. Understanding how higher temperatures may alter DENV transmission is essential to anticipate future dengue risk. Therefore, we assessed the effect of temperature on DENV-1 in Aedes aegypti from New Caledonia. Mosquitoes were orally infected and maintained for 14 days at 26.6 °C (average temperatures during recent outbreaks) or 31.1 °C (SSP5-8.5 scenario projected temperatures). Mosquito bodies, heads, and saliva were analysed separately to determine infection, dissemination, and transmission rates as well as transmission efficiencies. Infectious virus was detected by using a fluorescent focus assay, and viral titres were quantified via TCID50 assays. No significant differences were observed in infection, dissemination, and transmission rates or transmission efficiencies between the two temperatures. However, DENV titres in mosquito bodies and heads were significantly higher at 31.1 °C than 26.6 °C. Our results indicate that elevated temperature increases viral loads within the insect but not the proportion of infectious mosquitoes, highlighting the importance of considering temperature as a key parameter in assessing dengue risk under climate change. Further studies are needed to investigate the effects of temperature on virus–mosquito interactions.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11020052

Authors: Yutong Han Lixin Rao Yu Huang Qi Zhao Xin Shen Biao Xu

With population aging, the burden of tuberculosis (TB) among the elderly is rising. Older adults are at high risk of TB but susceptible to poor TB care. In this study, we enrolled TB patients aged over 60 years registered in Shanghai during 2019–2021. A seven-step care cascade from estimated TB burden in the community to treatment outcomes was constructed to quantify retention and attrition at each step of TB health service. Patient pathway analysis was carried out in two districts of Shanghai to describe patients’ care-seeking behaviors, service coverage, and diagnosis delays. Across the care cascade, the largest gaps occurred from symptom onset to care seeking (11.3%) and from treatment initiation to completion (10.7%). Male sex, older age, and mycobacterium tuberculosis positivity were associated with treatment discontinuation and unfavorable outcomes. The patient pathway analysis revealed that first contact at lower-level or non-TB-designated hospitals was associated with more complex pathways and may contribute to diagnostic delays. These findings highlight the need to promote proactive care seeking upon symptoms, strengthen targeted adherence support for older people, and improve diagnostic capacity and referral efficiency at lower-level health facilities.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11020051

Authors: Nicholas Zugno-Gadea Lázaro Molina Mariangela Hernandez-González María Mercedes Rueda Francis Bejarano Nelson Alexander Betancourt Ana Sanchez

Emerging evidence suggests that certain cestodes, including Taenia solium, may actively modulate the host’s hormonal and immune environment to facilitate their survival. This study aimed to determine whether patients diagnosed with neurocysticercosis (NCC) exhibit immunoendocrine alterations associated with infection. A clinical study was conducted in Honduras, enrolling 11 adult NCC patients (9 female, 2 male) and 11 age- and sex-matched healthy controls. Serum concentrations of seven hormones and two cytokines were evaluated. Compared to controls, NCC patients showed significantly elevated levels of 17β-Estradiol (E2), Progesterone (P4), Androstenedione (A4), Luteinizing Hormone (LH), Follicle-Stimulating Hormone (FSH), Interleukin-6 (IL-6), and Interleukin-10 (IL-10). Conversely, Free testosterone (FT) and Dihydrotestosterone (DHT) levels were significantly reduced. These findings support the hypothesis that T. solium may manipulate host immunoendocrine pathways to promote its establishment and persistence within the central nervous system.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11020050

Authors: Dina I. Bance-Anicama María M. Diaz-Orihuela Luz M. Diaz-Orihuela Wilter C. Morales-García

Background: In tropical regions, dengue and leptospirosis coexist and share a nonspecific clinical onset that hinders timely diagnosis. Coinfection may worsen the clinical course and increase mortality. Objective: To estimate the prevalence of dengue, leptospirosis, and coinfection among patients with febrile syndrome in Madre de Dios (Peru) and to identify associated clinical factors. Methods: Observational, analytical, cross-sectional, retrospective study conducted at a primary-level health facility. Clinical and laboratory records of patients with febrile syndrome seen in 2024 were analyzed. Categorical variables were summarized as frequencies (%) and numeric variables as mean ± SD or median [IQR]. Comparisons used chi-square or Fisher’s exact test, Student’s t test, or the Mann–Whitney U test, as appropriate. Associations were estimated using Poisson regression models with robust variance, adjusted for sex, reporting prevalence ratios (PRs) and 95% CIs. Analyses were performed in R 4.0.2. Results: A total of 226 patients were included. Positivity was 19.0% for dengue (43/226), 66.8% for leptospirosis (151/226), and 5.8% for coinfection (13/226). In the bivariate analysis, dengue was associated with higher temperature (p < 0.001), lower mean arterial pressure (p = 0.007), mucosal bleeding/ecchymosis (p = 0.049), and lower fluid intake (p = 0.021); temperature was also higher in coinfection (p = 0.021). In Poisson models, dengue was associated with tachycardia (PR = 5.69; 95% CI: 1.95–13.07; p < 0.001), temperature (PR = 1.61 per °C; 1.23–2.12; p = 0.001), bilateral polyarthralgia (PR = 2.55; 1.14–5.04; p = 0.012), and mucosal bleeding/ecchymosis (PR = 3.31; 0.94–8.37; p = 0.027). Leptospirosis was associated with male sex (PR = 0.78 vs. female; 0.65–0.94; p = 0.010) and fever (PR = 2.38; 1.17–6.03; p = 0.035). Leptospira–dengue coinfection was related to higher temperature (PR = 1.75 per °C; 1.05–3.01; p = 0.036). Conclusions: Simple clinical signs such as fever/elevated temperature, tachycardia, bilateral polyarthralgia, and mucosal bleeding can help prioritize suspicion of dengue, leptospirosis, or coinfection; guide requests for dual testing (dengue–Leptospira), early hydration in dengue, and timely initiation of antibiotic therapy in leptospirosis. These findings support the development of integrated triage algorithms and strengthening access to molecular diagnostics in high-burden febrile syndrome settings.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11020049

Authors: Iliyan Todorov Margarita Gospodinova Kalina Stoyanova

COVID-19, caused by SARS-CoV-2, is a highly contagious disease with variable clinical presentation. Severe forms are more common in patients with pre-existing chronic conditions. The objective of this study is to evaluate the prognostic value of the Charlson Comorbidity Index (CCI) in relation to disease severity and outcome in hospitalized COVID-19 patients with comorbidities. A retrospective analysis was conducted on 558 patients, hospitalized at the Infectious Diseases Clinic of “St. Marina” University Hospital, Varna, Bulgaria, between March 2020 and March 2021. CCI score was calculated to estimate 10-year survival probabilities. Prevalent comorbidities were arterial hypertension (78.55%), type 2 diabetes (16.09%), and ischemic heart disease (5.82%). A higher number of comorbidities was associated with increased rates of bilateral pulmonary consolidation (χ2 = 6.63, p = 0.010), oxygen therapy needs (χ2 = 5.41, p = 0.020), and mortality (χ2 = 7.88, p = 0.005). Patients with higher CCI scores had worse outcomes. A CCI score above 5 was common among non-survivors and those with pulmonary consolidation and respiratory failure. The findings confirm that advanced age and multiple comorbidities are strong predictors of poor COVID-19 prognosis. Early CCI calculation at hospital admission would help identify high-risk patients and support timely, targeted medical interventions.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11020048

Authors: Maria Ruano Camps Aleny Couto Irénio Gaspar Eudoxia Filipe Idilia Nhamtumbo Luis Armando Gil Muvale Ana Gabriela Gutierrez Zamudio Rosa Bene Jeff Lane Florindo Mudender Edy Nacarapa

Background: Cryptococcal meningitis (CM) remains a leading cause of mortality among people with advanced HIV disease (AHD) in sub-Saharan Africa. Current guidelines recommend induction therapy with amphotericin B and flucytosine, typically administered in an inpatient setting due to concerns over severe clinical presentation and drug-related toxicities. This requirement poses a significant burden on resource-limited health systems. We evaluated the real-world outcomes of a fully outpatient model for CM therapy in Maputo, Mozambique. Methods: A longitudinal retrospective cohort study was conducted at the Centro de Referência de Alto-Maé (CRAM), a specialized AHD outpatient clinic. We included 83 PLWH with laboratory-confirmed CM treated between October 2020 and December 2024. The primary outcome was hospitalization-free survival (HFS) within the first 10 weeks of treatment. Secondary outcomes included the frequency and severity of adverse drug reactions (ADRs), analysed by tracking haemoglobin (Hgb), potassium (K+), and creatinine (Creat) levels on days 1, 3, and 7 of induction therapy, and retention in care (RIC) at 6, 12, and 24 months. Statistical analyses included Kaplan–Meier survival estimates and paired t-tests. Results: The median age was 37 years (IQR: 27–42), 63.9% were male, and the median CD4 count was 62 cells/µL (IQR: 27–105). Most patients (95.2%) were symptomatic at presentation, and 56.6% had concurrent tuberculosis. For the 52 patients who completed the full induction protocol at CRAM, the HFS rate at 10 weeks was 84.6% (44/52), with an overall survival of 90.4% (47/52). ADR analysis (n = 52) showed a predictable pattern of mild, manageable toxicity: a significant decline in Hgb (11.2 ± 1.8 to 10.6 ± 2.0 g/dL, p < 0.001) and K+ (4.27 ± 0.66 to 3.86 ± 0.78 mmol/L, p = 0.008), and a transient increase in Creat (0.83 ± 0.42 to 1.13 ± 0.64 mg/dL, p = 0.001) from day 1 to day 3, with stabilization or a trend toward recovery by day 7. No significant differences in ADRs were found between single-dose (47%) and multiple-dose (53%) L-AmB regimens. RIC for the entire cohort (n = 83) was high at 81.9% at 6 months, declining to 74.0% at 12 months and 70.4% at 24 months. Conclusions: An ambulatory model for CM therapy is feasible and effective in a resource-limited setting, demonstrating high hospitalization-free survival, manageable and reversible adverse drug reactions, and excellent medium-term retention in care. These findings suggest potential benefits and provide support for re-evaluating the standard of inpatient care. They indicate that integrating outpatient CM management into advanced HIV disease (AHD) care packages could help alleviate health system burdens and may contribute to improved patient outcomes.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11020047

Authors: Kana Suzuki Asiko Ongaya Evans Amukoye Yasuhiko Kamiya

Tungiasis, caused by the sand flea Tunga penetrans, results in itching and pain. Effective treatments, such as dimeticones, are often unaffordable. A 3% phenothrin lotion has shown safety and efficacy in Kenyan trials. This study compared the cure rate and safety of 3% phenothrin lotion (as the intervention) and 0.05% potassium permanganate (KMnO4; as the standard-care comparator) over 14 days. This parallel-group, three-arm, non-blinded, randomised comparative trial was conducted in Vihiga County, Kenya. Participants aged ≥2 years with ≥1 viable flea on each foot were allocated (2:1:1) to KMnO4, single-dose 3% phenothrin, or two-dose 3% phenothrin groups. Overall, 415 fleas from 79 participants were followed up to day 14 (KMnO4, 213; single-dose, 129; two-dose, 73). On days 4 and 7, the single-dose phenothrin showed significantly higher cure rates (11.6% and 21.7%) than KMnO4 (0.9% and 11.7%) (p < 0.001 and p = 0.013). The differences diminished by days 10 and 14 because of spontaneous flea death. The cure rate of the two-dose group on day-7 (8.2%) was lower than that of the single-dose group. Single-dose 3% phenothrin improved early cure rates compared to KMnO4, but not by days 10–14; two-dose phenothrin showed no benefit compared with single dose from day 7 onwards.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11020046

Authors: Jacob Werner Rella Zoleko-Manego Ghyslain Mombo-Ngoma Michael Ramharter Johannes Mischlinger

Loiasis exists in regions where malaria is highly endemic, yet few studies have investigated their association as concomitant infectious diseases. Secondary data analysis from a cross-sectional survey conducted in Gabon (2015–2016) was performed to assess the association between malaria and loiasis. A total of 947 participants of all ages were enrolled in the original study. In crude analyses, malaria showed a seemingly protective association with loiasis, manifesting in an odds ratio (OR) of 0.67 (95% CI: 0.45 to 1.01; p = 0.0521). This borderline association disappeared completely after adjustment for confounders (adjusted OR: 1.31; 95% CI: 0.81 to 2.11; p = 0.276), particularly age. The apparent crude protective association is therefore likely explained by the different epidemiological distribution of both diseases according to age rather than a true biological interaction. Malaria predominantly occurred in children and loiasis mainly in older individuals. Findings of this study do not support an association between malaria and loiasis in this setting.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11020045

Authors: Elena Lampazzi Chiara Virgillito Beniamino Caputo Giulia Lombardi Greta Santarelli Riccardo Moretti Maurizio Calvitti

The Incompatible Insect Technique (IIT) is a species-specific, eco-friendly mosquito control method that relies on releasing Wolbachia-infected males, which induce cytoplasmic incompatibility (CI), rendering eggs inviable when mating with wild females. Aiming at optimizing IIT protocols in terms of cost-effectiveness, data on incompatible male dispersal and survival and the distance- and time-related impact of induced sterility are fundamental. This study plans to fill this gap and reports findings from a two-year field trial (2022–2023) at the ENEA-Casaccia Research Center, based on single-spot releases of incompatible Aedes albopictus males (ARwP strain). Male releases were carried out in late September 2022 (~15,000 released males) and the early Ae. albopictus season (at the end of June 2023; ~24,000 released males). Fifty-eight ovitraps were located at a 20–900 m distance from the ARwP release spot and were monitored weekly from May to November to assess egg hatching rates and measure CI effects in relation to both distance and time. Following the 2023 release, samples of adults were collected at increasing distances from the release site and at multiple post-release time points to assess, individually, wild female fertility and ARwP male dispersal and survival using Wolbachia as a genetic marker. Statistical analyses revealed that: (a) the highest reduction in the egg hatching was found within 100 m from the release spot (46.5% and 19.9%, respectively, in 2022 and 2023) but remained significant even at greater distances (29.9% and 7.7% at 300 m, respectively, in 2022 and 2023); (b) accordingly, the highest reduction in the wild female fertility occurred within 100 m from the release spot (47.3%), but similar effects were recognizable up to 600 m; (c) the overflooding ratio of the ARwP males did not significantly differ between 3 and 11 days after the release, with ARwP males remaining active up to 18 days and dispersing as far as 400 m. These results demonstrate the potential of localized, non-inundative IIT trials to furnish clues for the setup of spatially optimized release strategies, especially in scaled-up applications. The study also emphasizes the need for standardized assessment tools and further research regarding environmental and behavioral factors influencing long-term suppression outcomes.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11020043

Authors: Leiwen Fu Ke Liu Yuxian Sun Wei Shu Yujia Ning Yang Liu Jian Du Liang Li

Background: Tuberculosis remains a major global public health challenge, particularly among children. This study aims to provide a comprehensive assessment of the global, regional, and national burden of tuberculosis among children (0–14 years) using data from the Global Burden of Disease (GBD) 2021 study. Methods: Data on the incidence of tuberculosis (drug-susceptible, MDR-TB, and XDR-TB), as well as disability-adjusted life years (DALYs), among children aged 0–14 years in 204 countries and territories from 1990 to 2021 were obtained from the GBD 2021 study. Estimated annual percentage changes (EAPCs) in age-standardised incidence rates (ASIRs) and DALY rate were calculated overall and stratified by age, sex, and sociodemographic index (SDI) to quantify temporal trends. Spearman correlation analyses were performed to assess associations between tuberculosis burden and SDI. Results: In 2021, there were an estimated 759,300 new tuberculosis cases (ASIR: 37.7 per 100,000 population) among children globally, including 32,515 cases of MDR-TB (ASIR: 1.6) and 1193 cases of XDR-TB (ASIR: 0.1). Both global ASIR and DALY rate exhibited a declining trend from 1990 to 2021, with EAPC of −2.61% (95%CI: −2.74 to −2.47) and −4.38% (−4.61 to −4.14), respectively. From 1990 to 2021, High-income North America was the only GBD region with an increasing ASIR for tuberculosis (EAPC = 1.12, 95% CI: 0.61 to 1.64). From 1990 to 2021, there was no significant change in ASIR of MDR-TB (EAPC = 1.18, 95% CI: −0.16 to 2.54). However, eight of the 21 GBD regions exhibited increasing trends in the ASIR of MDR-TB, with the largest increase observed in Oceania (11.99, 10.49 to 13.52), followed by Central Asia (9.76, 6.48 to 13.13) and South Asia (5.71, 3.10 to 8.38). A strong negative correlation was observed between tuberculosis burden and SDI, with the highest disease burden concentrated in low-SDI regions. Conclusions: Achieving elimination targets will require stronger diagnostics and treatment for childhood tuberculosis, alongside reduced transmission, improved infection detection, and preventive therapy for exposed children, especially those under 5 years.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11020044

Authors: Penghui Jia Xiao Cong Chang Zhang Zhe Liu Xiaofang Peng Juan Su Qiqi Tan Shen Huang Changyun Sun Xin Zhang Baisheng Li

Chikungunya virus (CHIKV) poses an increasing global public health threat, as evidenced by the significant 2025 Foshan outbreak in China. Rapid, whole-genome sequencing (WGS) is critical for outbreak response but is challenged by primer mismatches across diverse lineages and a lack of direct sequencing platform comparisons. To address this, we developed a novel lineage-inclusive primer set and performed parallel WGS on 24 clinical samples from the outbreak using both Illumina (NGS) and Oxford Nanopore Technologies (TGS) platforms. Our lineage-inclusive primer set successfully amplified full-length CHIKV genomes across all samples. Comparisons revealed that Illumina NGS provided higher raw read accuracy, while Nanopore TGS achieved more complete coverage of terminal UTRs with a faster turnaround time. Crucially, after polishing, variant calls between the two platforms were 100% concordant. Phylogenetic analysis was consistent with a single introduction event, with all outbreak isolates forming a monophyletic clade within the ECSA lineage most closely related to contemporaneous strains from Réunion Island. This study validates a lineage-inclusive amplicon-based sequencing strategy and demonstrates that NGS and TGS offer complementary advantages. When integrated, they provide a robust framework for real-time genomic surveillance, enhancing preparedness and guiding public health interventions against CHIKV.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11020042

Authors: Mohamed Haidy Massa Osman Abdillahi Guedi Nicolas Gomez Ali Ould Mohamed Salem Boukhary Sébastien Briolant Mohamed Aly Ould Lemrabott

Malaria remains one of the main public health problems in Mauritania, and it is essential to identify the factors that determine the distribution and productivity of Anopheles breeding sites in order to develop more effective control strategies. A longitudinal survey with repeated measurements was conducted in Nouakchott between May 2023 and April 2024, in order to examine the factors influencing the distribution and productivity of Anopheles larval habitats. The larvae were collected by immersion in 60 water points, once a month during the dry season and twice a month during the rainy season, for a total of 294 observations. The physical and chemical characteristics of the sites were also measured. Logistic regression analyses with random effects showed that the presence of Culex and Aedes larvae, pH, and temperature were statistically significantly associated with positive water collection for Anopheles larvae (aOR = 3.03, 95%CI [1.14–8.07], p-value = 0.026; aOR = 0.18, 95%CI [0.05–0.60], p-value = 0.006; aOR = 3.17, 95%CI [1.32–7.61], p-value = 0.010 and aOR = 5.95, 95%CI [2.09–16.92], p-value < 0.001, respectively). Only Anopheles multicolor and An. arabiensis were present in Nouakchott. Our results could help health authorities by guiding the destruction of breeding sites with biological larvicides or physical elimination of peridomestic habitats.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11020041

Authors: Nanci Santos-Ferreira Clévio Nóbrega Marta Mota Luís Pereira de Almeida Leonel Pereira Teresa Gonçalves Célia Nogueira

Infectious diseases remain a major global health challenge, underscoring the need for safe and accessible antiviral therapies. Natural products, particularly marine macroalgae, are promising sources of bioactive compounds with antiviral properties. This study evaluated the antiviral activity of extracts from two red algae collected along the Portuguese coast: two life stages (tetrasporophyte and female gametophyte) of Chondracanthus teedei var. lusitanicus and the algae Osmundea pinnatifida. Antiviral effects were assessed against Coxsackievirus A12 (CVA12) and a lentivirus (LV) vector model. Extracts from both algae inhibited viral replication in vitro at non-cytotoxic concentrations. The tetrasporophyte extract of C. teedei exhibited virucidal activity against CVA12, and the results are consistent with interference with multiple stages of the viral life cycle, while also inducing an antiviral state in HEK-293T cells against LV infection. The female gametophyte extract affected early stages of CVA12 and LV infection and showed potential virucidal activity. O. pinnatifida demonstrated the strongest antiviral effects against both viruses. These findings highlight the antiviral potential of these red algal extracts and warrant further in vivo evaluation.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11020040

Authors: Thanh Huy Nguyen Nguyen Quoc Khanh Le

Dengue and chikungunya are endemic arboviral diseases in many low- and middle-income countries, often co-circulating and presenting with overlapping symptoms that hinder early diagnosis. Timely differentiation is critical, especially in resource-limited settings where laboratory testing is unavailable. We developed and evaluated machine-learning (ML)- and deep-learning (DL) models to classify dengue, chikungunya, and discarded cases using a large-scale, real-world dataset of over 6.7 million entries from Brazil (2013–2020). After applying the Synthetic Minority Oversampling Technique (SMOTE) to address class imbalance, we trained six ML models and one artificial neural network (ANN) using only demographic, clinical, and comorbidity features. The Random Forest model achieved strong multi-class classification performance (Recall: 0.9288, the Area Under the Curve (AUC): 0.9865). The ANN model excelled in identifying chikungunya cases (Recall: 0.9986, AUC: 0.9283), suggesting its suitability for rapid screening. External validation confirmed the generalizability of our models, particularly for distinguishing discarded cases. Our models demonstrate high-accuracy in differentiating dengue and chikungunya using routinely collected clinical and epidemiological data. This work supports the development of Artificial Intelligence-powered decision-support tools to assist frontline healthcare workers in under-resourced settings and aligns with the One Health approach to improving surveillance and diagnosis of neglected tropical diseases.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11020039

Authors: Cecília Ferreira de Mello Wellington Thadeu de Alcantara Azevedo Shayenne Olsson Freitas Silva Samara Campos Alves Jeronimo Alencar

Mosquitoes (Diptera: Culicidae) exhibit vertical stratification patterns in forest environments, a fundamental ecological aspect for understanding niche occupation patterns, host-seeking behavior, and consequently arbovirus transmission mechanisms. Despite the relevance of this topic, available studies mostly focus on genera such as Aedes, Haemagogus, and Sabethes which are traditionally associated with arbovirus transmission. There are still important gaps regarding stratification and seasonality in the Mansoniini tribe, whose biology and epidemiological role remain underexplored, especially in highly biodiverse ecosystems such as the Atlantic Forest. This study evaluated the influence of seasonality and vertical stratification on the mosquito community, with a detailed focus on the Mansoniini tribe, in an Atlantic Forest fragment in Brazil, between May 2023 and December 2024. Captures were performed monthly using CDC light traps positioned at 1.5 m and 10 m heights, and specimens were morphologically identified. A total of 880 mosquitoes from nine genera and 24 species were captured, of which 91 (10.3%) belonged to the Mansoniini tribe. The most abundant species were Coquillettidia fasciolata and Mansonia titillans, recorded in both strata. Our results indicate no marked vertical segregation for the studied mosquito community in this specific location, but a strong influence of seasonality, particularly for the Mansoniini tribe, reinforcing the role of meteorological data on the population structure of these species. These site-specific findings offer a foundational ecological portrait and a robust methodological template for a neglected taxon. They generate critical, testable hypotheses about niche partitioning in fragmented forests and underscore the necessity for broader spatial replication to disentangle the relative influence of seasonal versus vertical drivers in similar ecosystems.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11020038

Authors: Muhamad Riduan Daud Petrick Periyasamy Kok-Yong Chin Najma Kori Ummu Afeera Zainulabid Sheng Qian Yew Nur Ezzaty Mohammad Kazmin Xiong Khee Cheong

Background and objectives: Low bone mineral density (BMD) is a recognized complication in people living with HIV (PLHIV) that remains under-addressed, particularly in Malaysia. Known contributing factors for low BMD include advanced age, HIV infection itself, and prolonged use of anti-retroviral therapy (ART), particularly tenofovir-based regimens. There are limited data on the burden of low BMD in the HIV population in Malaysia. This study aimed to determine the prevalence of low BMD among men living with HIV on tenofovir disoproxil fumarate (TDF) and to identify the possible associated factors compared to a group of healthy individuals matched for age and ethnicity. Methods: This is single-center cross-sectional study involved 112 men (56 HIV-positive individuals and 56 uninfected individuals matched for age and ethnicity) who underwent dual-energy X-ray absorptiometry (DXA) scans of the femoral neck and lumbar spine. Sociodemographic, clinical lifestyle, and laboratory data, including FRAX scores for those aged more than 40 years old, were collected. Results: The prevalence of low BMD at the femoral neck in HIV-infected men on tenofovir disoproxil fumarate was significantly higher compared to healthy individuals (32.1% vs. 16.1%; p < 0.05). Low BMD prevalence at the lumbar spine was higher in the HIV group (8.9% vs. 3.6%; p = 0.463) but was not statistically significant. Older age and low body mass index (BMI) were found to be significantly associated with reduced BMD in HIV patients. Chronic kidney disease stage 2 and 3a was linked with low femoral neck BMD. HIV-related factors (duration of illness, duration of ART exposure, and CD4+ counts) showed no significant associations to low BMD. The 10-year risk of major osteoporotic and hip fractures estimated by the FRAX tool was low in both groups, and no participant exceeded the recommended intervention threshold. Conclusions: Men with HIV on tenofovir disoproxil fumarate have a higher prevalence of low BMD, particularly at the femoral neck. Traditional risk factors were more closely associated with low BMD compared to HIV-related factors and specific markers, supporting the need for routine bone health screening and preventive strategies in this population.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11020037

Authors: Alexa Tabackman Sadie Cowan Claire Calderwood Pranay Sinha

Tuberculosis (TB) rarely occurs in isolation; most people with TB experience multiple coexisting conditions, including HIV, diabetes, undernutrition, depression, and substance use disorders, which worsen disease severity and compromise treatment outcomes. Although the World Health Organization has issued disease-specific guidance for managing key comorbidities, TB care remains largely siloed and poorly equipped to address the growing burden of multimorbidity, particularly in African health systems. In this perspective article, we propose a phased framework for multimorbidity-centered TB care. The first phase emphasizes systematic screening for common comorbidities and establishment of basic referral pathways. The second phase focuses on strengthening coordination between TB programs and existing health and social services, including task sharing and longitudinal follow-up. The third phase advances toward fully integrated, co-located, multidisciplinary models of care that embed TB services within broader multimorbidity platforms. Together, this framework offers a pragmatic roadmap for TB programs to deliver more person-centered, equitable, and efficient care, strengthen primary care systems, and accelerate progress toward ending TB as a public health threat in Africa.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11020036

Authors: Geofrey Amanya Sumbul Hashmi Jessica Sarah Stow Philip Tumwesigye Bernadette Nkhata Kelvin Roland Mubiru Anne-Laure Budts Matthys Gerhardus Potgieter Seyoum Dejene Balcha Muzamiru Bamuloba Andiswa Zitho Luzze Henry Mary G. Nabukenya-Mudiope Caroline Van Cauwelaert

Tuberculosis remains a major public health concern in Uganda, one among the thirty high TB burden countries globally. Despite national progress, gaps persist due to asymptomatic disease, diagnostic limitations, and uneven access to healthcare within the country. This study implemented the Epi-control platform, an AI-driven predictive modelling tool, to predict community-level hotspots and support data-driven active case-finding (ACF). Using retrospective chest X-ray screening data, we integrated demographic, environmental, and human development indicators from open-source databases to model TB risk at sub-parish level. A proprietary Bayesian modelling framework was deployed and validated by comparing TB yields between predicted hotspots and non-hotspot locations. Across Uganda, the model identified significantly higher TB yields in hotspot areas (risk ratio = 1.69, 95% CI 1.41–2.02; p < 0.001). The Central and Western regions showed the highest concentrations of hotspots, consistent with their population density and urbanization patterns. The results show that the model prioritized areas with higher observed ACF yield in this retrospective dataset, supporting its potential operational use for screening prioritization under similar implementation conditions. The results demonstrate that AI-based predictive modelling can enhance the efficiency of ACF by targeting high-risk areas for screening. Integrating such predictive tools within national TB programmes may support screening planning and resource prioritization; prospective evaluation and external validation are needed to assess generalisability and incremental impact.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11020035

Authors: Juan Ignacio Degiuseppe Paula Mabel Moron Christian Barrios Mathieur Argentinean Surveillance Network for Viral Gastroenteritis Argentinean Surveillance Network for Viral Gastroenteritis

Enteric adenoviruses are recognized causes of pediatric acute gastroenteritis, yet national-level data on their epidemiology and genetic diversity in Argentina remain limited. This study aimed to describe the laboratory-based surveillance of enteric adenoviruses and to characterize the circulating genotypes among children during the 2022–2024 period. Data were obtained from the Argentine National Health Surveillance System, including weekly aggregated reports of adenovirus testing results from clinical laboratories nationwide. Detection frequencies were analyzed by year, age group, clinical setting, geographic region, and epidemiological week. Molecular characterization was performed using partial hexon gene sequencing. A total of 22,826 stool samples were tested, of which 1530 (6.7%) were positive for adenovirus, with no significant differences in positivity across years. Detection rates were highest among children under 1 year of age and were consistently greater in outpatient and emergency department settings compared with hospitalized patients. No clear seasonal pattern was observed. Genotyping revealed a predominance of HAdV-F41, with sporadic detection of non-enteric adenovirus types. These findings provide the first nationwide overview of enteric adenovirus circulation and genetic diversity in Argentina, highlighting stable transmission patterns and supporting the value of sustained laboratory surveillance to better characterize viral gastroenteritis etiology in the post-rotavirus vaccination era.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11020034

Authors: Kun Wang Tian Tian Yunhai Guo Muxin Chen Xiaonen Wu Zhiying Hou Binbin Xie Fanna Wei Zhiheng Qi Zhisheng Dang Dingwei Sun Yang Hong Jun-Hu Chen Yue Wang

Angiostrongylus cantonensis (A. cantonensis) is the primary causative agent of human angiostrongyliasis and is widely distributed in Southeast Asia and China, with increasing reports from the Americas. Achatina fulica (A. fulica), Pomacea canaliculata (P. canaliculata), and slugs constitute established intermediate hosts of A. cantonensis, whereas Camaena hainanensis (C. hainanensis) has been newly reported as a host species in Hainan. A TaqMan quantitative PCR (qPCR) method assay targeting a novel genomic region of A. cantonensis was developed to detect infection in 150 snails collected from Hainan Province, China. The assay was employed to detect the parasite larvae across various snail tissues (lung sac, mucus, and foot), and its performance was compared with conventional lung sac microscopy. Out of the 120 A. fulica examined, 75 tested positive using the qPCR assay, yielding a significantly higher detection rate than lung-sac examination (p < 0.05). Significant differences were also observed in the positivity rates across the three snail tissues (lung sac, mucus, and foot) (p < 0.05), with the lung sac showing the highest rate of infection. Importantly, the detection of A. cantonensis DNA in snail mucus highlights its potential for development as a non-invasive diagnostic sample. Additionally, C. hainanensis was identified as a new host of A. cantonensis in Hainan, suggesting its possible contribution to parasite transmission. The newly developed qPCR assay demonstrated superior sensitivity (reflected by lower Ct values) compared with previously published TaqMan qPCR methods. The established qPCR method provides a sensitive and non-invasive tool for detecting A. cantonensis in snails, and can be applied for monitoring and early warning of parasite prevalence and transmission.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11010033

Authors: Adriana E. Flores Jesus A. Davila-Barboza Alan E. Juache-Villagrana

Insecticide-based strategies have been central to vector control programs targeting diseases of human and veterinary importance for decades [...]

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11010032

Authors: Jean-Philippe Chippaux Fabien Taieb

As Wüster et al [...]

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11010031

Authors: Wolfgang Wüster David A. Warrell David J. Williams

One of the major obstacles to improving the management of snakebite envenoming is the lack of accurate identification of species responsible for clinical cases, which prevent the improvement of definitions of species-specific syndromes [...]

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11010030

Authors: Longyu Chen Yi Yuan Yu Xia Jiang Long Zhijin Li Tingting Li Li Qi

(1) Background: Human rabies continues to be a significant public health challenge and imposes a heavy disease burden. The epidemiological characteristics and post-exposure prophylaxis (PEP) of human rabies in Chongqing were analyzed to provide a scientific basis for its prevention and control in Chongqing. (2) Methods: Data and case investigation forms of the human rabies epidemic in Chongqing from 2016 to 2024 were collected and analyzed using descriptive epidemiological methods. (3) Results: From 2016 to 2024, 84 human rabies cases were reported in Chongqing, with an average annual incidence rate of 0.03 per 100,000 population. Among the cases, 72.6% were aged 45 and above. Farmers constituted the primary infected group (73.8%). Analysis of exposure patterns and PEP revealed that 92.4% of cases involved dog transmission, with domestic dogs responsible for 65.2% and stray dogs for 31.8%. After exposure, 51.5% received no treatment, while only 6 individuals were vaccinated against rabies. (4) Conclusions: Although rabies incidence in Chongqing is low, dogs remain the primary source, and post-exposure vaccination is often delayed. Strengthening health education and dog immunization is crucial for supporting the global “Zero by 30” target.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11010029

Authors: Jelena Prpić

Neglected tropical diseases (NTDs) comprise a diverse group of infections that disproportionately affect impoverished populations in tropical and subtropical regions [...]

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11010028

Authors: Holly Jian Harriet Lawford Angus McLure Colleen Lau Adam Craig

Following World Health Organization (WHO) validation of lymphatic filariasis (LF) elimination as a public health problem, countries are required to implement post-validation surveillance (PVS) to detect potential resurgence and ensure sustained elimination. WHO’s guidelines released in 2025 recommend implementation of at least two of four PVS strategies—targeted surveys, integration into standardised surveys, health facility-based screening, and molecular xenomonitoring (MX) of mosquitoes. This review synthesised global evidence on PVS activities from 2007 to 2025 in the 23 countries and territories validated as having eliminated LF. Studies were identified through PubMed, Scopus, Embase, Web of Science, and the WHO Institutional Repository for Information Sharing (IRIS). Data on publication information, surveillance strategies, priority populations, and operational challenges and enablers were extracted. Narrative synthesis using deductive content analysis was applied. Thirty documents from 17 countries were included. Targeted surveillance and integration of PVS with other health programmes were the most common approaches noted (reported in ten and nine countries, respectively), followed by MX (seven countries) and health facility-based screening (four countries). Surveillance often focused on migrants and previous hotspots, with operational challenges linked to limited funding, workforce, and supply chains. Documents indicated that Sri Lanka, Thailand, China, and South Korea developed sustained PVS through national policies and domestic funding. Findings highlight the need for clear, contextualised guidance to operationalise sustainable PVS in different settings.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11010027

Authors: Harriet L. S. Lawford Holly Jian ‘Ofa Tukia Joseph Takai Clément Couteaux ChoCho Thein Ken Jetton Teanibuaka Tabunga Temea Bauro Roger Nehemia Charlie Ave Grizelda Mokoia Peter Fetaui Fasihah Taleo Cheryl-Ann Udui Colleen L. Lau Adam T. Craig

Eight Pacific Island Countries and Territories (PICTs) have been validated by the World Health Organization (WHO) as having eliminated lymphatic filariasis (LF) as a public health problem. WHO recommends that these countries implement post-validation surveillance (PVS) to ensure resurgence has not occurred. Some PICTs proactively conducted LF PVS even in the absence of specific recommendations or best-practice guidelines at the time of implementation. We aimed to explore the barriers and facilitators to implementing LF PVS in PICTs, with a view to informing context-specific strategies and regional guidelines. Key informant interviews were held between March and September 2024 with 15 participants involved in LF and/or neglected tropical disease surveillance. Transcripts were analysed thematically using a generalised deductive approach. A conceptual framework was developed to summarise themes with two main streams of barriers identified. Stream One Barriers included limited awareness of, and guidelines for, PVS requirements and competing national health priorities. Stream Two Barriers included cost, resource, and logistical barriers to conducting PVS. Participants called for clearer, contextually tailored guidelines, improved communication from WHO, and integration within existing systems. This study highlights the urgent need for operational guidance, policy advocacy, and capacity strengthening to ensure sustainable LF PVS in PICTs. Incorporating local context and leveraging existing health structures will be essential to prevent disease resurgence and maintain gains achieved through elimination programmes.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11010026

Authors: Johnson Matowo Njelembo J. Mbewe Salum Azizi Robert Kaaya Oliva Moshi Baltazari Manunda Emmanuel Feston Ezekia Kisengwa Agness Msapalla Steve Crene Oscar Sizya Benson Mawa Godwin Sumari Boniface Shirima Silvia Mwacha Felister Edward Amandus Joram Filemoni Tenu Neema Kaaya Naomi J. Lyimo Franklin Mosha

A new generation of insecticide-treated nets (ITNs) that incorporate the synergist piperonyl butoxide (PBO) has been shown to restore susceptibility to pyrethroids where P450 enzymes are the primary mechanism conferring the resistance. The present study evaluated the efficacy of YAHE 4.0, a PBO ITN, against wild free-flying Anopheles arabiensis in experimental huts in Lower Moshi, north-eastern Tanzania. It is the first evaluation of YAHE 4.0 in the country. Bio-efficacy evaluations, including susceptibility tests and cone bioassays, were conducted using the standard WHO guidelines. DuraNet Plus, a WHO-recommended PBO ITN, and Interceptor ITNs served as active and standard comparators, respectively. Unwashed and 20 times washed nets were subjected to experimental hut trials. Multiple logistic regression was employed to analyse experimental hut trial data. The results of the susceptibility testing showed that the An. arabiensis population of Lower Moshi was resistant to pyrethroids, but susceptible to organophosphates. Particularly, low mortality was recorded for cyhalothrin (2%) and alpha-cypermethrin (38%). Mortality rates to alpha-cypermethrin pirimiphos-methyl were 38% and 100%, respectively. The non-inferiority of YAHE 4.0 to DuraNet Plus ITN in terms of mortality and blood feeding was determined according to the WHO guidelines. The results for pooled unwashed and 20 times washed ITNs showed that YAHE 4.0 was superior to Interceptor ITN (adjusted odds ratio, AOR = 1.33; 95% CI = 1.04–1.69; non-inferiority margin, NIM = 0.68; p-value = 0.023) and non-inferior to DuraNet Plus (AOR = 1.02; 95% CI = 0.78–1.35; NIM = 0.72; p-value = 0.867) in terms of mortality. In terms of blood feeding inhibition for pooled unwashed and 20× washed ITNs, YAHE 4.0 was superior to both Interceptor ITN (AOR = 0.80; 95% CI = 0.64–1.00; NIM = 1.35; p-value = 0.049) and DuraNet Plus (AOR = 0.67; 95% CI = 0.52–0.86; NIM = 1.33; p-value = 0.002). Chemical analysis showed higher wash retention of active ingredients in YAHE 4.0 LLIN (88.9% for PBO and 94.9% for alpha-cypermethrin) compared to DuraNet Plus LLIN (89.2% for PBO and 90.5% for alphaypermethrin) before the hut trial. YAHE 4.0 LLIN demonstrated superior entomological efficacy and wash durability to DuraNet Plus and Interceptor LLINs, and fulfilled WHO non-inferiority criteria for mosquito mortality and blood-feeding inhibition. Therefore, YAHE 4.0 LLIN should be considered as an addition to the current list of pyrethroid-PBO nets used for control of pyrethroid-resistant vector populations with P450 enzymes as the main mechanism conferring resistance.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11010025

Authors: Yasir Alruwaili

Schistosomiasis remains a major neglected tropical disease globally and presents particular challenges for countries transitioning from control to elimination. Saudi Arabia represents a unique epidemiological setting, having shifted from historical endemic transmission to very low reported incidence, yet long-term national analyses remain limited. A retrospective longitudinal analysis of national schistosomiasis surveillance data from 2002 to 2024 was conducted to evaluate temporal trends, clinical subtypes, regional distribution, and demographic characteristics. Joinpoint regression was used to identify significant changes in temporal trends, and autoregressive integrated moving average (ARIMA) models were applied to forecast national and regional trajectories. National incidence declined markedly from 5.5 per 100,000 in 2002 to 0.12 per 100,000 in 2024, with a notable change around 2010, followed by sustained low-level incidence. Intestinal schistosomiasis accounted for most cases, with increasing concentration among adult non-Saudi males and near-elimination among children. Regionally, cases were confined to a limited number of western and southwestern regions, particularly Ta’if, Al Baha, Jazan, and Madinah. Forecasting analyses indicated continued low-level detection without evidence of national resurgence. These findings demonstrate a transition to an elimination-maintenance phase and highlight the need for sustained surveillance in historically endemic regions and mobile populations.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11010024

Authors: Uwem F. Ekpo Jacob Solomon Hammed O. Mogaji Francisca O. Olamiju Fajana Oyinlola Ijeoma Achu Olanike O. Oladipupo Alice Y. Kehinde Imaobong O. Umah Fatai Oyediran Moses Aderogba Louise K. Makau-Barasa

As Nigeria advances toward the elimination of soil-transmitted helminthiasis (STH), updated endemicity maps are essential for guiding programmatic decisions. A cross-sectional study was conducted to update the STH endemicity maps in ten local government areas (LGAs) of Ondo State from July to August 2024. LGAs were stratified into three categories (C1–C3) based on the history of preventive chemotherapy (PC), with C1 being endemic LGAs with ≥5 effective rounds of PC, C2 being endemic LGAs with <5 effective rounds of PC, and C3 being low-endemicity (STH prevalence <20%; PC not required). A total of 4507 school-aged children (5–14 years) from 151 systematically selected communities (15 per LGA) provided fresh stool samples to assess the prevalence and intensity of STH. Stool samples were examined using the Kato-Katz technique. Prevalence of STH was aggregated at the LGA level and compared with World Health Organization thresholds. In the first category (C1), the baseline prevalence was reduced significantly by 60–96%, with specific prevalence in Akoko Southwest (from 28.2% to 0.4%, Risk Ratio (RR): 0.01), Akure North (from 39% to 1.5%, RR = 0.04), Ifedore (from 25% to 2.5%, RR = 0.10), and Ondo East (from 45.2% to 8.2%, RR = 0.18). In the second category (C2), the baseline was reduced significantly by 66–100%, with Akure South (from 29% to 1.2%, RR = 0.04), Ose (from 20% to 2.2%, RR = 0.11), Owo (~100% reduction), and Odigbo (38% to 12.8%, RR = 0.34). In the C3 LGAs, infection was significantly below the baseline threshold, with Akoko Northwest (5.2% to 0.9%, RR = 0.17) and Idanre (from 14.2% to 1.8%, RR = 0.13). Overall, significant reductions in STH prevalence were observed across the surveyed LGAs, with risk ratios ranging from 0.04 to 0.40. These findings updated the endemicity map for the ten LGAs in Ondo State, demonstrating significant progress toward STH elimination following PC implementation.

Tropical Medicine and Infectious Disease doi: 10.3390/tropicalmed11010023

Authors: Darrel Ornelle Elion Assiana Franck Hardain Okemba-Okombi Salomon Tchuandom Bonsi Freisnel Hermeland Mouzinga Juliet E. Bryant Jean Akiana Tanou Joseph Kalivogui Alain Disu Kamalandua Nuccia Saleri Lionel Caruana Hugues Traoré Asken Dissou Affolabi

National Tuberculosis Reference Laboratories (NTRLs) are central to tuberculosis (TB) control programs. Between 2018 and 2024, the Republic of Congo, a country of 6 million inhabitants, achieved a transformative strengthening of its TB diagnostic system, coordinated by the NTRL. Strategic investments, supported mainly by international partners, enabled a substantial decentralization of services, expanding the diagnostic network from 38 to 113 diagnostic and testing centers and increasing GeneXpert sites from 3 to 31. The expansion of the diagnostic network and specimen referral system was associated with a reduced structural gap in diagnostic coverage by extending access to GeneXpert testing to a larger number of peripheral and previously underserved centers. Critically, the establishment of a BSL-3 laboratory and the deployment of advanced assays like Xpert MTB/XDR ended the reliance on overseas testing by introducing in-country capacity for multidrug-resistant and pre-extensively drug-resistant TB detection. These systemic improvements were associated with significant positive outcomes, including an annual molecular testing surging from 11,609 in 2022 to over 27,000 in 2024 and bacteriological confirmation rates rising from 34 to 73%. This comprehensive laboratory systems strengthening, which also facilitated cross-programmatic initiatives like HIV and Mpox testing integration, underscores how sustained investment in infrastructure, logistics, and quality management is fundamental to improving case detection, surveillance, and progress toward the WHO End TB Strategy milestones.