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Trop. Med. Infect. Dis., Volume 11, Issue 6 (June 2026) – 28 articles

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11 pages, 1646 KB  
Article
Molecular Identification of Schistosoma Species Associated with Atypical Urinary Eggs in Abuja (Nigeria): Evidence of Potential Zoonotic Transmission
by Solomon Monday Jacob, Sophie Y. Akinbo, Oluwaremilekun G. Ajakaye, Uwem F. Ekpo, Zainab Omoruyi, Temitope Agbana, Louise Makau-Barasa, Moses O. Aderogba, Jan-Carel Diehl, David Bell, Adedotun A. Bayegun, Michael A. Okungbowa, Juliana A-Enegela and Frederick O. Akinbo
Trop. Med. Infect. Dis. 2026, 11(6), 170; https://doi.org/10.3390/tropicalmed11060170 - 22 Jun 2026
Viewed by 778
Abstract
Schistosomiasis remains a major public health concern in Nigeria. We molecularly characterized Schistosoma eggs obtained from human urine to identify species and assess the presence of hybrid schistosomes in Abuja, Nigeria. Urine samples were collected from 1887 participants aged five years and above. [...] Read more.
Schistosomiasis remains a major public health concern in Nigeria. We molecularly characterized Schistosoma eggs obtained from human urine to identify species and assess the presence of hybrid schistosomes in Abuja, Nigeria. Urine samples were collected from 1887 participants aged five years and above. Samples were examined for Schistosoma eggs using light microscopy. A total of 507 (26.9%) were positive for any form of Schistosoma while 91 (4.8%) had atypical Schistosoma eggs. DNA extracted from pooled ova was analyzed using metagenomic sequencing, read mapping, phylogenetic analysis, and BLASTn confirmation. Molecular analyses identified genetic signatures associated with both S. haematobium and S. bovis within pooled human urine samples, indicating the co-circulation of multiple schistosome species in the study area. Phylogenetic analyses based on trans-ITS and mitochondrial COX1 markers supported the presence of distinct nuclear and mitochondrial schistosome lineages. However, because sequencing was performed on pooled egg samples, the findings cannot distinguish between true recombinants and mixed infections involving co-circulating parental species. These findings highlight the potential complexity of schistosome transmission dynamics in endemic communities and underscore the need for enhanced molecular surveillance, especially single-parasite genomic approaches, and integrated One Health investigations to better understand schistosome transmission and its implications for control and elimination efforts in Nigeria. Full article
(This article belongs to the Special Issue Advances in Parasitic Neglected Tropical Diseases—2nd Edition)
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14 pages, 893 KB  
Article
Imported Tungiasis in Greece: Secondary Household Transmission and Transient Mixed Liver Enzyme Elevation
by Thomas Fotas, Ioannis A. Giantsis, Menelaos Lefkaditis, Ioannis S. Pappas, Mathis A. B. Christodoulopoulos, Efterpi Zafiriou, Electra Nicolaidou, Alexander C. Katoulis and Georgios Christodoulopoulos
Trop. Med. Infect. Dis. 2026, 11(6), 169; https://doi.org/10.3390/tropicalmed11060169 - 21 Jun 2026
Viewed by 299
Abstract
Tungiasis is a cutaneous ectoparasitosis caused by the penetration of gravid female Tunga penetrans fleas into the epidermis. Although endemic in tropical and subtropical regions, it remains rare in Europe, where most cases are travel-associated and secondary household transmission is seldom documented. This [...] Read more.
Tungiasis is a cutaneous ectoparasitosis caused by the penetration of gravid female Tunga penetrans fleas into the epidermis. Although endemic in tropical and subtropical regions, it remains rare in Europe, where most cases are travel-associated and secondary household transmission is seldom documented. This study describes imported tungiasis in Greece and investigates possible secondary household transmission in a non-endemic setting. Seven Greek men residing in Attica developed tungiasis following occupational exposure in Tanzania, together with one secondary case in a non-travelling household contact who had never travelled outside Greece. Diagnosis was based on clinical and dermoscopic findings and confirmed by amplification and sequencing of the mitochondrial cytochrome oxidase I (COI) gene. Household investigations were also performed. Eight male patients presented with painful plantar and/or subungual nodular lesions. Sequence analysis of COI demonstrated 657/662 bp (99%) identity with the Tunga penetrans reference sequence, and identical sequences were identified in all samples. A representative sequence was deposited in GenBank (accession no. PZ336383). All patients exhibited mild-to-moderate elevations of hepatocellular and cholestatic liver enzymes, which resolved within two weeks following treatment. One probable secondary household case was identified, and no infestation was detected among additional cohabitants or companion animals. This report documents imported tungiasis with probable secondary household transmission in Greece and highlights the importance of clinical awareness and environmental assessment in non-endemic settings. Full article
(This article belongs to the Section Neglected and Emerging Tropical Diseases)
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10 pages, 1518 KB  
Article
Implementation of Open PCR System for the Detection of TB/DR-TB and NTM in Sputum Samples from Suspected Pulmonary Tuberculosis Patients in Medan, Indonesia
by R Lia Kusumawati, Mirzan Hasibuan, Nisrina Tari, Gema Nazri Yanni, Laura Isa Ginting, Cynthia Gozali and Tryna Tania
Trop. Med. Infect. Dis. 2026, 11(6), 168; https://doi.org/10.3390/tropicalmed11060168 - 18 Jun 2026
Viewed by 452
Abstract
(1) Background: Indonesia faces the dual challenge of a high tuberculosis (TB) burden and increasing drug resistance. Conventional molecular diagnostics frequently fail to detect isoniazid resistance and nontuberculous mycobacteria (NTM). This study evaluates a domestic multiplex Open PCR system in Medan, Indonesia. (2) [...] Read more.
(1) Background: Indonesia faces the dual challenge of a high tuberculosis (TB) burden and increasing drug resistance. Conventional molecular diagnostics frequently fail to detect isoniazid resistance and nontuberculous mycobacteria (NTM). This study evaluates a domestic multiplex Open PCR system in Medan, Indonesia. (2) Methods: From July to November 2025, 1569 sputum specimens from suspected TB patients were analysed using the Indigen MTB/NTM/DR-TB Real-time PCR Kit Gen 2. (3) Results: Mycobacterial DNA was detected in 421 specimens (26.8%). Among these, 396 (94.1%) were drug-susceptible TB, while 16 (3.8%) showed resistance, predominantly INH mono-resistance (n = 14; 0.89% of total). Additionally, 9 cases (2.1%) involved NTM or TB-NTM co-infections. Tertiary hospitals showed significantly higher positivity rates (33.5%) than primary care (18.9%; p < 0.001). TB status was significantly associated with male (p = 0.0052) and older age (p = 0.006), whereas resistance profiles and NTM distribution were consistent across all demographic groups (p > 0.80). (4) Conclusions: This study describes the implementation and diagnostic yield of a domestic multiplex Open PCR system in Medan, Indonesia. By bridging diagnostic gaps across a decentralized referral network, this facilitates rapid and targeted therapy. Integrating multiplex domestic innovations into national diagnostic algorithms is essential for achieving Indonesia’s TB elimination targets. Full article
(This article belongs to the Special Issue Tuberculosis Diagnosis: Current, Ongoing and Future Approaches)
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17 pages, 2667 KB  
Article
Anti-Dengue IgG Seroprevalence and Exposure-Related Risk in Italian Military Personnel Deployed on Overseas Missions: A Cross-Sectional Study
by Andrea Ciammaruconi, Anna Rocchetti, Filippo Molinari, Elisa Recchia, Nathalie Totaro, Chiara Pascolini, Silvia Chimienti, Giovanni Faggioni, Riccardo De Santis, Filippo Moramarco, Alberto Autore and Florigio Lista
Trop. Med. Infect. Dis. 2026, 11(6), 167; https://doi.org/10.3390/tropicalmed11060167 - 18 Jun 2026
Viewed by 345
Abstract
Dengue virus infection remains a significant public health challenge in endemic regions, with growing evidence of autochthonous transmission in Europe. Assessing serological exposure in high-risk populations such as military personnel deployed to endemic areas is essential to quantify exposure risk and support operational [...] Read more.
Dengue virus infection remains a significant public health challenge in endemic regions, with growing evidence of autochthonous transmission in Europe. Assessing serological exposure in high-risk populations such as military personnel deployed to endemic areas is essential to quantify exposure risk and support operational decision-making, particularly regarding pre-deployment counselling and risks associated with secondary infection. We conducted a cross-sectional study involving 1355 members of the Italian Armed Forces, measuring anti-dengue IgG antibodies by ELISA and collecting data on deployment history and exposure risk. Overall, IgG seropositivity was 8.12%, with significantly higher prevalence among individuals reporting travel or deployment to endemic regions (24.71%) compared with non-exposed personnel (4.27%). Seropositivity increased with age and correlated with a CDC-derived cumulative dengue risk score (Spearman’s ρ = 0.299, p < 0.0001). A multivariable logistic regression model including age and exposure risk achieved an AUC of 0.75, while machine-learning models provided complementary predictive assessment, with random forest reaching an AUC of 0.79. These findings indicate substantial anti-dengue IgG seropositivity compatible with previous dengue exposure among Italian military personnel, particularly those deployed to endemic settings. The study highlights the need for targeted surveillance and risk-based preventive strategies, and supports the use of exposure-based models to improve epidemiological assessment and inform vaccination strategies in mobile populations. Full article
(This article belongs to the Section Neglected and Emerging Tropical Diseases)
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16 pages, 4357 KB  
Article
Borrelia miyamotoi in Saint Petersburg and Leningrad Oblast, Russia: A Multi-Level Assessment of Ticks, Rodents, and Human Exposure
by Ivan Lyzenko, Olga Stukolova, Nikolay Tokarevich, Marina Sokolova, Regina Baimova, Islam Karmokov, Ekaterina Riabiko, Daria Grechishkina, Gelena Lunina and Vladimir Dedkov
Trop. Med. Infect. Dis. 2026, 11(6), 166; https://doi.org/10.3390/tropicalmed11060166 - 18 Jun 2026
Viewed by 397
Abstract
Background: Borrelia miyamotoi is an emerging tick-borne pathogen causing relapsing fever in humans. Although Saint Petersburg and the surrounding Leningrad Oblast harbor a high abundance of ixodid ticks (I. ricinus, I. persulcatus), no integrated assessment has yet simultaneously addressed [...] Read more.
Background: Borrelia miyamotoi is an emerging tick-borne pathogen causing relapsing fever in humans. Although Saint Petersburg and the surrounding Leningrad Oblast harbor a high abundance of ixodid ticks (I. ricinus, I. persulcatus), no integrated assessment has yet simultaneously addressed pathogen circulation in vectors, reservoir hosts, and human populations in this specific northwestern region of Russia. Methods: During 2022–2024, we collected 1518 questing adult ticks and trapped 516 small mammals in Saint Petersburg and Leningrad Oblast. B. miyamotoi DNA was detected by real-time PCR. Sera from 3743 randomly selected volunteers (1553 from Saint Petersburg, 2190 from Leningrad Oblast) were tested for anti-B. miyamotoi IgG/IgM using a protein microarray (antigens: GlpQ, Vmps, flagellin). Infection rates and seroprevalence with 95% Wilson confidence intervals were compared using chi-square tests. Results: The overall tick infection rate was 3.78% (57/1506). I. ricinus had a significantly higher prevalence (4.94%; 95% CI: 3.67–6.60%) than I. persulcatus (2.29%; 95% CI: 1.39–3.74%; p = 0.011). Ticks from Leningrad Oblast also showed markedly elevated infection rates (4.98%; 95% CI: 3.75–6.58%) compared to those from Saint Petersburg (1.89%; 95% CI: 1.06–3.35%; p = 0.004). Small mammals exhibited substantially higher infection rates in Leningrad Oblast (39.44%; 95% CI: 31.78–47.65%) than in Saint Petersburg (13.90%; 95% CI: 10.76–17.78%; p < 0.001). Bank voles (Myodes glareolus) and yellow-necked mice (Apodemus flavicollis) were the main reservoirs; synanthropic rodents trapped within the city were found to be infected for the first time. No significant organotropism was detected, but positive correlations between infection in the heart, liver, and kidney suggested hematogenous dissemination. The overall human seroprevalence of B. miyamotoi was 1.71% (95% CI: 1.34–2.18%) and was significantly higher in Leningrad Oblast (2.19%; 95% CI: 1.66–2.89%) than in Saint Petersburg (1.03%; 95% CI: 0.64–1.67%; p = 0.010). In contrast, the seroprevalence of B. burgdorferi s. l. did not differ between the two regions (approximately 5.1%). Conclusions: This first comprehensive, multi-level investigation in Saint Petersburg and Leningrad Oblast reveals a stable epidemiological gradient: natural foci in Leningrad Oblast sustain higher B. miyamotoi circulation in ticks and rodents, which translates into a two-fold higher exposure of the rural population. The findings highlight the need to include B. miyamotoi in regional tick-borne infection surveillance programs and to adopt differentiated risk assessment strategies for urban and rural settings. Full article
(This article belongs to the Special Issue Emerging Vector-Borne Diseases and Public Health Challenges)
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18 pages, 1751 KB  
Article
Determinants of Rabies Post-Exposure Prophylaxis Compliance in Bangladesh: Informing Policy for Elimination by 2030
by Sumon Ghosh, Mohammad Nayeem Hasan, Sukanta Chowdhury, Narayan C. Paul, Waqas Ahmad, Jiangang Chen and Thankam S. Sunil
Trop. Med. Infect. Dis. 2026, 11(6), 165; https://doi.org/10.3390/tropicalmed11060165 - 18 Jun 2026
Viewed by 448
Abstract
Rabies remains a preventable yet fatal zoonotic disease and a major public health concern in Bangladesh, which aims to eliminate dog-mediated human rabies by 2030. Despite free availability of post-exposure prophylaxis (PEP), adherence to the WHO-recommended PEP regimen remains low. This study assessed [...] Read more.
Rabies remains a preventable yet fatal zoonotic disease and a major public health concern in Bangladesh, which aims to eliminate dog-mediated human rabies by 2030. Despite free availability of post-exposure prophylaxis (PEP), adherence to the WHO-recommended PEP regimen remains low. This study assessed PEP compliance and identified determinants of regimen completion among animal-exposed patients. We conducted a hospital-based observational study using secondary data from 457 patients who initiated PEP at the National Rabies Prevention and Control Centre (NRPCC) in Dhaka, from February 2023 to July 2023. Sociodemographic, clinical, and exposure-related factors were analyzed to identify predictors of compliance. Only 17.1% of patients completed the full PEP regimen, including rabies immunoglobulin (RIG) administration for WHO Category III exposures where indicated. Higher adherence was observed among females, individuals aged ≥15 years, lower-income groups, and those residing within 10 km of the treatment center. Exposure-related factors including dog bites, multiple exposures, unprovoked incidents, and appropriate exposure care were also associated with improved compliance. Despite free access, PEP completion remains critically low. Targeted strategies, including decentralized PEP delivery, improved public awareness, and strengthened follow-up systems, are essential to improve adherence and support progress toward rabies elimination by 2030. Full article
(This article belongs to the Special Issue Recent Advances in Rabies Surveillance and Control)
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10 pages, 1055 KB  
Article
Rickettsia parkeri as a Probable Agent of Mild Spotted-Fever Group Rickettsiosis Identified by Seroreactivity in Villeta, Colombia
by Carlos Ramiro Silva-Ramos, Peter C. Melby, Patricia V. Aguilar, Miguel M. Cabada, Juan David Rodas, Marylin Hidalgo and Álvaro A. Faccini-Martínez
Trop. Med. Infect. Dis. 2026, 11(6), 164; https://doi.org/10.3390/tropicalmed11060164 - 18 Jun 2026
Viewed by 385
Abstract
Spotted fever group (SFG) rickettsioses are emerging zoonotic diseases of increasing relevance in Latin America, yet the specific species involved in human infections remain poorly defined in many endemic regions. This study aimed to determine the most probable antigen among SFG-seroreactive febrile patients [...] Read more.
Spotted fever group (SFG) rickettsioses are emerging zoonotic diseases of increasing relevance in Latin America, yet the specific species involved in human infections remain poorly defined in many endemic regions. This study aimed to determine the most probable antigen among SFG-seroreactive febrile patients from Villeta, Colombia. A panel of 25 convalescent-phase serum samples previously identified as positive for SFG Rickettsia spp. antibodies was analyzed by indirect immunofluorescence assay using antigens of Rickettsia rickettsii, R. amblyommatis and R. parkeri. Antibody titers were compared to identify differential seroreactivity patterns. Overall, 44% (11/25) of the samples showed differential antibody titers against one of the tested antigens. Among these, nine (36%) exhibited higher titers to R. parkeri and two (8%) to R. amblyommatis, while none showed exclusive reactivity to R. rickettsii. The remaining 56% (14/25) presented similar titers across antigens, consistent with indeterminate or cross-reactive SFG responses. Antibody titers ranged from 1:128 to 1:4096, with R. parkeri showing the strongest reactivity. These findings suggest R. parkeri or a highly related Rickettsia species as the predominant probable antigen in Villeta, highlighting its potential role in mild rickettsial infections and emphasizing the need for eco-epidemiological studies to identify local vectors and reservoirs. Full article
(This article belongs to the Special Issue Latin American Tropical Diseases: Epidemiology & Prevention)
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13 pages, 1513 KB  
Article
Serological, Molecular, and Epidemiological Investigation of Toxoplasma gondii Infection in Blood Donors from the Brazilian Semiarid Region
by Basílio Felizardo Lima Neto, Ana Caroline Dantas Amorim, Maria Jessianny Diniz Alves, Ana Maria Santos Lima, Janielton Albuquerque Lima, Celine Sousa Menezes Sá, Emilly Henrique Silva, João Luís Garcia, Vinicius Longo Ribeiro Vilela and Thais Ferreira Feitosa
Trop. Med. Infect. Dis. 2026, 11(6), 163; https://doi.org/10.3390/tropicalmed11060163 - 17 Jun 2026
Viewed by 390
Abstract
This study aimed to determine the prevalence and risk factors associated with Toxoplasma gondii infection in blood donors from the Brazilian Semiarid region, and to explore its implications for transfusion safety. Samples were collected from 646 donors at blood donation centers in the [...] Read more.
This study aimed to determine the prevalence and risk factors associated with Toxoplasma gondii infection in blood donors from the Brazilian Semiarid region, and to explore its implications for transfusion safety. Samples were collected from 646 donors at blood donation centers in the states of Ceará and Paraíba. Serological diagnosis was performed using BIOLISA TOXOPLASMOSE ELISA kits for anti-T. gondii IgM and IgG antibodies, and molecular diagnosis was conducted by conventional PCR targeting a 529-bp noncoding repetitive fragment. Epidemiological questionnaires on variables associated with infection were administered, and statistical analysis was performed in univariate and multivariate stages, using multiple logistic regression. Among the 646 donors, 43.4% (281/646) were positive for anti-T. gondii IgG antibodies, 0.3% (2/646) for IgM antibodies, and none tested positive by PCR. In the univariate analysis, age, family income, educational level, salad washing practices, water source, raw milk consumption, and duration as a donor were significantly associated, whereas in the multivariate analysis only “age” and “salad washing practices” remained significant. A substantial IgG seroprevalence was observed among blood donors in the Brazilian Semiarid. The low IgM frequency, concurrent IgG positivity, and negative PCR results are consistent with a low transfusion risk in the region. However, these findings should be interpreted cautiously, as negative PCR results do not completely rule out the presence of circulating parasites. Age was identified as a risk factor, whereas proper salad washing showed a protective effect. Full article
(This article belongs to the Special Issue Toxoplasma and Neospora: Public Health Challenges in Tropical Regions)
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16 pages, 766 KB  
Article
Detection of Dengue Virus and Serological Evidence of Chikungunya and Zika Virus Exposure in Patients with Acute Febrile Syndrome in Córdoba, Colombia
by Paula A. Avilés-Vergara, Dina Ricardo-Caldera, Carlos Alberto Bolívar Pineda, Eliud Daniel Pérez Vergara, Ana Carolina Negrette Oquendo, Luis Carlos Ruiz Garces, Sara Cecilia Soto-De León and Catalina Tovar-Acero
Trop. Med. Infect. Dis. 2026, 11(6), 162; https://doi.org/10.3390/tropicalmed11060162 - 17 Jun 2026
Viewed by 382
Abstract
Background/Objectives: Arboviral diseases transmitted by Aedes mosquitoes, including Dengue (DENV), Zika (ZIKV), and Chikungunya (CHIKV), represent a major public health challenge in tropical regions. Their clinical similarity complicates differential diagnosis, particularly in settings of viral co-circulation, and may lead to underdiagnosis. The [...] Read more.
Background/Objectives: Arboviral diseases transmitted by Aedes mosquitoes, including Dengue (DENV), Zika (ZIKV), and Chikungunya (CHIKV), represent a major public health challenge in tropical regions. Their clinical similarity complicates differential diagnosis, particularly in settings of viral co-circulation, and may lead to underdiagnosis. The objective was to detect acute dengue infection and assess serological evidence of Chikungunya and Zika virus exposure among patients with acute febrile syndrome and clinical suspicion of dengue in the department of Córdoba, Colombia. Methods: A prospective descriptive study was conducted between 2023 and 2024 in healthcare institutions in Montería and Sahagún. Serum samples were analyzed by ELISA to detect DENV NS1 antigen, anti-CHIKV IgM, and anti-ZIKV IgG antibodies. Sociodemographic, clinical, and laboratory variables were described, and the association between prior ZIKV infection and dengue severity was assessed. Results: Ninety patients were included. Isolated laboratory marker detection was observed for DENV NS1 antigen in 36.7% (33/90), anti-ZIKV IgG in 30.0% (27/90), and anti-CHIKV IgM in 2.2% (2/90); combined arboviral markers were identified in 22.2% (20/90), and 8.9% (8/90) had no detectable markers. Among NS1-confirmed dengue cases (n = 47), 61.7% (29/47) were classified as dengue with warning signs. Anti-ZIKV IgG detection was not associated with dengue clinical classification (p = 0.989), although platelet counts were lower in IgG-positive cases (p = 0.037). Conclusions: The findings support laboratory-supported diagnosis and integrated acute febrile illness surveillance in Córdoba, including locally adapted vector control, in a setting of arbovirus co-circulation with overlapping laboratory markers. Full article
(This article belongs to the Section Vector-Borne Diseases)
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24 pages, 685 KB  
Review
Crimean–Congo Hemorrhagic Fever Virus in Africa: Epidemiological Trends, Transmission Ecology, Hotspot Heterogeneity, and Preparedness Challenges—A Narrative Review
by Elichilia Robert Shao, Jeremia J. Pyuza, Tito Kibona, Laura Shirima, Eliaichi A. Mlay, Alice Andongolile, Ray Kayaga, Semvua Kilonzo, Blandina T. Mmbaga and Jaffu Chilongola
Trop. Med. Infect. Dis. 2026, 11(6), 161; https://doi.org/10.3390/tropicalmed11060161 - 16 Jun 2026
Viewed by 544
Abstract
Background: Crimean–Congo hemorrhagic fever virus (CCHFV) is an important tick-borne zoonosis and an emerging public health threat across Africa. Although evidence of viral circulation is mounting, information remains fragmented, limiting a comprehensive understanding of transmission ecology, regional hotspot heterogeneity, and preparedness needs across [...] Read more.
Background: Crimean–Congo hemorrhagic fever virus (CCHFV) is an important tick-borne zoonosis and an emerging public health threat across Africa. Although evidence of viral circulation is mounting, information remains fragmented, limiting a comprehensive understanding of transmission ecology, regional hotspot heterogeneity, and preparedness needs across the continent. Methods: This narrative review critically synthesized published literature on CCHFV in Africa, identified through PubMed, Scopus, and Google Scholar and supplemented by citation tracking and authoritative public health reports. Evidence from epidemiological, ecological, molecular, surveillance, and One Health studies was integrated to examine transmission dynamics, geographic hotspot distribution, viral diversity, risk factors, diagnostic and surveillance challenges, and preparedness strategies. Results: Available evidence shows marked geographic heterogeneity in CCHFV transmission across Africa, with hotspot regions shaped by ecological suitability, Hyalomma tick distribution, livestock–human interactions, and health system capacity. Livestock consistently show higher exposure than humans, underscoring their role as key indicators of viral circulation. Diagnostic limitations, passive surveillance, ecological variability, and serological cross-reactivity contribute to substantial under recognition of disease burden, while molecular studies reveal considerable viral diversity and ongoing evolution across African regions. Conclusions: CCHFV remains underdiagnosed and underreported in many African settings because of limited surveillance and diagnostic capacity. Strengthening integrated One Health surveillance, expanding laboratory and genomic capacity, utilizing livestock as sentinel populations, and improving cross-sectoral collaboration are critical for enhancing early detection, outbreak preparedness, and effective public health response across the continent. Full article
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12 pages, 249 KB  
Systematic Review
The Impact of HIV Viral Suppression and Immune Status on Rifampicin-Resistant Tuberculosis Outcomes: A Systematic Review and Meta-Analysis Protocol
by Tukisho Mphahlele, Thendo Gertie Makhado and Lufuno Makhado
Trop. Med. Infect. Dis. 2026, 11(6), 160; https://doi.org/10.3390/tropicalmed11060160 - 15 Jun 2026
Viewed by 332
Abstract
Background/Objectives: Rifampicin-resistant tuberculosis (RR-TB) and HIV co-infection remain major contributors to morbidity and mortality, particularly in high-burden settings. HIV-related clinical factors, including viral suppression, CD4-defined immune status, HIV drug resistance, virological failure, and ART failure, may influence RR-TB treatment response; however, existing evidence [...] Read more.
Background/Objectives: Rifampicin-resistant tuberculosis (RR-TB) and HIV co-infection remain major contributors to morbidity and mortality, particularly in high-burden settings. HIV-related clinical factors, including viral suppression, CD4-defined immune status, HIV drug resistance, virological failure, and ART failure, may influence RR-TB treatment response; however, existing evidence remains fragmented. This systematic review and meta-analysis protocol aims to synthesize evidence on the impact of HIV viral suppression, immune status, and HIV drug resistance/ART resistance status on RR-TB treatment outcomes. Methods: This protocol was developed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols guidelines. Published peer-reviewed studies and relevant grey literature from January 2005 to December 2025 will be searched in PubMed/MEDLINE, Cochrane Library, Embase, Web of Science, ScienceDirect, EBSCOhost, PsycINFO, Google Scholar, and other relevant sources. No language restriction will be applied at the search stage. Where feasible, non-English records will be translated for title/abstract and full-text screening. Two reviewers will independently screen studies, extract data, and assess study quality, with disagreements resolved by a third reviewer. Study-level risk of bias will be assessed using design-appropriate tools, and the certainty of evidence for each outcome will be evaluated using GRADE. Results: Evidence will be synthesized narratively and, where studies are sufficiently homogeneous, quantitatively through meta-analysis. Outcomes of interest will include treatment success, treatment failure, mortality, treatment completion, microbiological cure, and adverse events. Subgroup analyses will be considered by viral suppression status, CD4-defined immune status, HIV drug resistance/ART resistance status, geographic region, and treatment regimen where data permit. Conclusions: This review will provide evidence on how HIV viral suppression, immune status, and HIV drug resistance/ART resistance influence RR-TB treatment outcomes. The findings may inform integrated TB/HIV care, clinical monitoring, and treatment strategies for individuals co-infected with HIV and RR-TB. Full article
(This article belongs to the Special Issue HIV Testing, Prevention and Care Interventions, 2nd Edition)
9 pages, 543 KB  
Brief Report
Post-Deployment Screening of Thailand Military Units Deployed to South Sudan from 2023 to 2025 Reveals High Rates of Sub-Microscopic P. falciparum Malaria
by Min Kramyoo, Sidhartha Chaudhury, Watcharee Yokanit, Kamonwan Siriwattanakul, Porruthai Kittikanara, Brian A. Vesely, Darunee Utennam, Nakarin Sansanayudh and Sutchana Tabprasit
Trop. Med. Infect. Dis. 2026, 11(6), 159; https://doi.org/10.3390/tropicalmed11060159 - 15 Jun 2026
Viewed by 328
Abstract
Peacekeeping operations in sub-Saharan Africa continue to be impacted by malaria both in-country and among returning service members. The Royal Thai Army (RTA) deploys an engineering company to Juba and Rumbek, South Sudan to conduct peacekeeping operations as part of the UN Mission [...] Read more.
Peacekeeping operations in sub-Saharan Africa continue to be impacted by malaria both in-country and among returning service members. The Royal Thai Army (RTA) deploys an engineering company to Juba and Rumbek, South Sudan to conduct peacekeeping operations as part of the UN Mission in South Sudan (UNMISS). Each deployment is approximately 12 months long. The unit is given doxycycline one week before travel before switching to the UN-provided mefloquine during deployment and for four weeks after returning. The RTA routinely conducts post-deployment screening for malaria by microscopy and PCR for units returning from UNMISS. High rates of prophylaxis failure were observed from both during-mission and post-deployment screening cases, with cumulative malaria attack rates of 11.4% (31 cases out of 271 personnel), 18.2% (49 cases out of 270 personnel), and 23.1% (63 cases out of 273 personnel) for 2023, 2024, and 2025, respectively, with 98% of cases being due to P. falciparum. Furthermore, post-deployment screening revealed high rates of sub-microscopic and sub-clinical parasitemia with 40% of all malaria cases being identified as asymptomatic during post-deployment screening, and 61% of those asymptomatic cases being detected by PCR only. While factors underlying the high prophylaxis failure rate, as well as the high rate of sub-microscopic and sub-clinical parasitemia are unclear, these findings highlight the limitations of relying on clinical symptoms or microscopy for detecting malaria in military units returning from endemic regions and underscore the importance of unit-wide post-deployment molecular screening. Full article
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18 pages, 8950 KB  
Article
Reduced HAV IgG Seropositivity Among Unvaccinated People Living with HIV: The Weak Shield
by Huan Xu, Sheng Huang, Haotian Huang, Xinrui Gao, Chunlin Chen, Guangyu Liang, Aili Lu, Xuwen Xu, Yuyuan Xu, Hao Wang, Xin Tao and Shaohang Cai
Trop. Med. Infect. Dis. 2026, 11(6), 158; https://doi.org/10.3390/tropicalmed11060158 - 11 Jun 2026
Viewed by 359
Abstract
People living with HIV (PLWH) represent a high-risk population for hepatitis A virus (HAV) infection, with exposure risk equal to or higher than that of the general population, particularly within adult risk networks. Anti-HAV immunoglobulin G (IgG) serves as a neutralizing antibody and [...] Read more.
People living with HIV (PLWH) represent a high-risk population for hepatitis A virus (HAV) infection, with exposure risk equal to or higher than that of the general population, particularly within adult risk networks. Anti-HAV immunoglobulin G (IgG) serves as a neutralizing antibody and is considered a key marker of protective immunity against HAV infection. However, the serologic profile of anti-HAV IgG and IgM among unvaccinated PLWH remains insufficiently characterized, especially in South China. A total of 1232 unvaccinated adults were enrolled in the study, including 800 PLWH and 432 HIV- negative controls, to evaluate the serological markers of HAV immunity. Serum anti-HAV IgG and immunoglobulin M (IgM) were measured using enzyme-linked immunosorbent assays, and demographic, immunological, and biochemical data were collected. We observed that PLWH had significantly lower anti-HAV IgG concentrations (0.27 ± 0.16 vs. 0.31 ± 0.14 ng/mL, p < 0.001) and a lower IgG seropositivity rate (22.5% vs. 35.6%, p < 0.001) compared with HIV-negative controls, whereas no differences were found in IgM levels or positivity between the two groups. Multivariable logistic regression identified HIV infection (OR = 0.599, 95% CI 0.413–0.869, p = 0.007) and age (OR = 1.019, 95% CI 1.007–1.031, p = 0.002) as independent factors associated with IgG seropositivity. Among PLWH, those who were IgG-positive tended to be older (p = 0.003) and had higher serum globulin levels (p < 0.001), whereas IgM positivity was linked to younger age (p < 0.001) and a higher CD4/CD8 ratio (p = 0.030). Age-stratified analyses further revealed that IgG seroprevalence increased with age, while IgM positivity showed a declining trend. These findings indicate a considerable immunity gap in a population at elevated risk of HAV infection and support the need for targeted serologic screening and vaccination strategies among PLWH. Full article
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17 pages, 1429 KB  
Article
Rapid and Sensitive Detection of Schistosoma mansoni in the Intermediate Snail Hosts Using Loop-Mediated Isothermal Amplification (LAMP) Diagnostics
by Hong-Mei Li, Zhi-Qiang Qin, Shan Lv, Jing Xu, Nicholas Midzi, Masceline Jenipher Mutsaka-Makuvaza, Ting Feng, Robert Bergquist and Xiao-Nong Zhou
Trop. Med. Infect. Dis. 2026, 11(6), 157; https://doi.org/10.3390/tropicalmed11060157 - 11 Jun 2026
Viewed by 424
Abstract
Schistosomiasis is an important snail-borne neglected tropical disease, and detecting infected snails is a priority for its control and elimination. However, conventional parasitological methods, such as crushed snails and cercarial shedding, have limited sensitivity. In this study, we developed a novel loop-mediated isothermal [...] Read more.
Schistosomiasis is an important snail-borne neglected tropical disease, and detecting infected snails is a priority for its control and elimination. However, conventional parasitological methods, such as crushed snails and cercarial shedding, have limited sensitivity. In this study, we developed a novel loop-mediated isothermal amplification (LAMP) assay (smND1-LAMP) targeting the mitochondrial NADH dehydrogenase subunit 1 (ND1) gene of Schistosoma mansoni. The assay was optimized at 65 °C for 1 h and demonstrated a detection limit of one copy of the pUC57/smND1 recombinant plasmid. Its diagnostic performance was evaluated using laboratory-infected Biomphalaria snails and field-collected samples from Zimbabwe and Burkina Faso, and compared with microscopy, conventional PCR and SYBR Green real-time PCR (SGPCR). In laboratory experiments, smND1-LAMP achieved 100% specificity and 75% sensitivity, outperforming microscopy and showing a similar performance to SGPCR. In field surveys, smND1-LAMP detected a higher positive rate (25.9%) than conventional PCR (22.2%) in Burkina Faso, while microscopy failed to identify any positive snails. Both molecular methods identified infections that were missed by parasitological techniques. These findings demonstrate that smND1-LAMP assay is a sensitive, specific, and field-applicable tool for detecting S. mansoni infection in snails. It provides an effective alternative for routine surveillance and early warning of changing schistosomiasis endemicity. Full article
(This article belongs to the Section Neglected and Emerging Tropical Diseases)
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15 pages, 1210 KB  
Article
Factors Associated with Virological Non-Suppression Among People Living with HIV Receiving Antiretroviral Therapy in Kazakhstan: A National Registry-Based Study
by Anel Ibrayeva, Zhamilya Nugmanova, Anarkhan Nurkerimova, Aigerim Alimbekova, Marat Tukeyev, Alfiya Denebaeva, Jack DeHovitz, Yerlan Ismoldayev, Bolat Sadykov, Shynar Tanabayeva and Ildar Fakhradiyev
Trop. Med. Infect. Dis. 2026, 11(6), 156; https://doi.org/10.3390/tropicalmed11060156 - 9 Jun 2026
Viewed by 323
Abstract
Background: Virological suppression is a key outcome of antiretroviral therapy. Despite progress in HIV treatment in Kazakhstan, virological non-suppression remains a relevant clinical and public health issue requiring further analysis. This study aimed to assess the prevalence of virological suppression (VS) and [...] Read more.
Background: Virological suppression is a key outcome of antiretroviral therapy. Despite progress in HIV treatment in Kazakhstan, virological non-suppression remains a relevant clinical and public health issue requiring further analysis. This study aimed to assess the prevalence of virological suppression (VS) and to identify factors associated with the absence of VS among people living with human immunodeficiency virus (HIV) who are receiving antiretroviral therapy (ART) in Kazakhstan. Methods: A retrospective cross-sectional analytical study was conducted using secondary analysis of a de-identified national registry database of people living with HIV (PLHIV) receiving ART in the Republic of Kazakhstan as of 30 September 2025. The primary outcome was virological non-suppression (VNS), defined as the last viral load (VL) value of at least 200 copies per milliliter. The analysis included sex, age, presumed route of HIV transmission, the first available cluster of differentiation 4 (CD4) cell count recorded in the registry, the last recorded percentage category of adherence to ART, and the aggregated category of ART regimen. The main descriptive, bivariate, and multivariable analyses were performed using a complete-case approach. Independent associations were assessed using multivariable logistic regression, and the results were presented as adjusted odds ratios (aORs) with 95 percent confidence intervals (CIs). Results: The initial registry extraction included 33,614 records, of which 32,130 patients were included in the final analytical sample. VS was achieved in 29,454 (91.7%) patients, whereas VNS was observed in 2676 (8.3%) patients. In the multivariable model, higher adjusted odds of VNS were observed among men compared with women (aOR 1.14; 95% CI 1.02–1.26), as well as among patients with a first CD4 count < 200 cells/μL compared with those with a first CD4 count of ≥500 cells/μL (aOR 1.25; 95% CI 1.09–1.44). The strongest association was found for reduced adherence to therapy. Compared with adherence of at least 95%, the adjusted odds of VNS were markedly higher among patients with adherence of 85–94% (aOR 28.66; 95% CI 25.85–31.77) and among those with adherence below 85% (aOR 61.05; 95% CI 50.50–73.81). In all age groups older than 25 years, the adjusted odds of VNS were lower than among patients younger than 25 years. Lower adjusted odds of VNS were also observed among patients with homosexual transmission, vertical transmission, and other or unspecified transmission routes compared with heterosexual transmission. Among ART regimens, regimens containing non-nucleoside reverse transcriptase inhibitors (NNRTIs) were associated with lower adjusted odds of VNS than dolutegravir-containing regimens (DTG-containing regimens) (aOR 0.68; 95% CI 0.52–0.88), whereas no statistically significant differences were identified for regimens containing protease inhibitors (PIs). Conclusions: Despite the high overall level of VS among PLHIV receiving ART in Kazakhstan, VNS remains concentrated in clinically and programmatically important subgroups. It was most strongly associated with reduced adherence and was also associated with younger age, marked baseline immunosuppression, and male sex in the primary model. These findings support the need for targeted interventions focused on adherence support, early diagnosis, and differentiated long-term follow-up of patients. Full article
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8 pages, 1878 KB  
Case Report
Cutaneous Larva Migrans Acquired in a Tropical Area of Ecuador: Diagnostic Delay, Clinical Evolution, and Recognition Challenges
by Verónica Salomé Sánchez-Peralta, Katherine Lizeth Moposa-Balarezo, Fabio Marcelo Idrovo-Espín and Rommy Terán
Trop. Med. Infect. Dis. 2026, 11(6), 155; https://doi.org/10.3390/tropicalmed11060155 - 8 Jun 2026
Viewed by 383
Abstract
Cutaneous Larva Migrans (CLM) is a neglected tropical disease (NTD) caused by zoonotic Ancylostomatidae larvae, mainly Ancylostoma braziliense and Ancylostoma caninum, which infect dogs and cats. Humans are accidental hosts, acquiring infection when L3 larvae in contaminated soil penetrate the skin, producing [...] Read more.
Cutaneous Larva Migrans (CLM) is a neglected tropical disease (NTD) caused by zoonotic Ancylostomatidae larvae, mainly Ancylostoma braziliense and Ancylostoma caninum, which infect dogs and cats. Humans are accidental hosts, acquiring infection when L3 larvae in contaminated soil penetrate the skin, producing serpiginous, pruritic lesions. We report a 24-year-old female from Quito, Ecuador, who developed a pruritic lesion on her right foot nine days after walking barefoot on wet, potentially fecally contaminated sand at Atacames Beach. Initial self-treatment with benzyl benzoate and herbal washes, followed by misdiagnoses as scabies and plantar warts, delayed proper care. Lesions progressed over three weeks with intense pruritus and functional impairment. CLM was correctly diagnosed by a podiatric technician 26 days post-exposure. Oral albendazole (400 mg/day for 4 days) led to rapid symptomatic relief within three days, with complete resolution by day 50. A survey analyzed by the McNemar Test revealed difficulties in recognizing early-stage CLM, regardless of experience or region among participants. Prevention requires personal protection, environmental sanitation, and regular anthelmintic treatment of dogs and cats. This case underscores the clinical consequences of delayed or incorrect diagnosis and highlights the need for enhanced healthcare training and One Health measures to reduce zoonotic diseases in Ecuador. Full article
(This article belongs to the Section Neglected and Emerging Tropical Diseases)
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16 pages, 1137 KB  
Article
Persistent Burden of Schistosomiasis in South Africa: A National Laboratory-Based Analysis, 2019–2024
by Charlotte Sriruttan-Nel, Bhavani Moodley, John Frean, Dumisani Mlotshwa and Veerle Msimang
Trop. Med. Infect. Dis. 2026, 11(6), 154; https://doi.org/10.3390/tropicalmed11060154 - 5 Jun 2026
Viewed by 489
Abstract
Schistosomiasis remains the second leading cause of death among parasitic diseases globally, contributing substantially to chronic morbidity and disability. South Africa (SA) is endemic for schistosomiasis, with ongoing efforts to expand mass drug administration. In the absence of true prevalence data, this study [...] Read more.
Schistosomiasis remains the second leading cause of death among parasitic diseases globally, contributing substantially to chronic morbidity and disability. South Africa (SA) is endemic for schistosomiasis, with ongoing efforts to expand mass drug administration. In the absence of true prevalence data, this study retrospectively analysed public sector laboratory-confirmed schistosomiasis cases from 2019 to 2024. Over this period, 73,680 cases were microscopically diagnosed, with Schistosoma haematobium accounting for 99.9% of infections. The test positivity rate of 20 per 100,000 population is lower than previously reported, with the burden concentrated among boys aged 5–19 years, particularly in the KwaZulu-Natal, Limpopo, and Mpumalanga provinces. These findings highlight a persistent burden within defined demographic groups and geographic areas, while also suggesting possible early signs of improvement that are potentially linked to public health interventions. The results provide valuable evidence to inform the scale-up of national schistosomiasis control programmes and the prioritisation of interventions towards the most affected populations. Full article
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33 pages, 3880 KB  
Review
Reducing Antibiotic Dependence in Poultry: The Potential of Phytochemicals as Antibiotic Alternatives Against Bacterial Foodborne Pathogens
by Rithu Chandran, Thomas Denagamage, Daniel M. Czyz, Subhashinie Kariyawasam and Abraham Joseph Pellissery
Trop. Med. Infect. Dis. 2026, 11(6), 153; https://doi.org/10.3390/tropicalmed11060153 - 4 Jun 2026
Viewed by 663
Abstract
Antimicrobial resistance (AMR) is one of the most serious threats to global public health, driven in part by extensive antibiotic use in food-producing animals. The poultry industry, a major contributor to the global animal protein supply, has depended on antibiotics for growth promotion [...] Read more.
Antimicrobial resistance (AMR) is one of the most serious threats to global public health, driven in part by extensive antibiotic use in food-producing animals. The poultry industry, a major contributor to the global animal protein supply, has depended on antibiotics for growth promotion and disease control, thereby contributing to the emergence and dissemination of AMR zoonotic bacteria. This review synthesizes current evidence on the potential of phytochemicals (PCs), plant-derived bioactive compounds, as sustainable non-antibiotic alternatives for controlling bacterial foodborne pathogens in poultry. Relevant literature including in vitro and in vivo studies assessing PCs against major poultry-associated zoonotic bacteria, including Salmonella enterica, Campylobacter spp., Clostridium perfringens, Listeria monocytogenes, and pathogenic Escherichia coli, is examined. Evidence indicates that PCs exert antimicrobial and anti-virulence effects through mechanisms like bacterial membrane disruption, inhibition of quorum sensing and virulence gene expression, modulation of gut microbiota, and enhancement of host immune responses. In vivo studies demonstrate reductions in pathogen colonization and improvements in gut health and performance metrics in poultry. Despite these promising findings, challenges remain in bioavailability, dose optimization, standardization, and regulatory approval. Overall, PCs represent a promising component of integrated antimicrobial stewardship strategies in poultry production, with significant implications for mitigating zoonotic AMR transmission. Full article
(This article belongs to the Special Issue Zoonotic Pathogens and Antimicrobial Resistance)
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14 pages, 17168 KB  
Article
Clinical Features, Treatment, and Outcomes of Mucormycosis: A Retrospective Analysis of 13 Cases from a Single Center in Turkey (2015–2025)
by Esma Kepenek Kurt, Rukiyye Bulut, Bahar Kandemir and İbrahim Erayman
Trop. Med. Infect. Dis. 2026, 11(6), 152; https://doi.org/10.3390/tropicalmed11060152 - 3 Jun 2026
Viewed by 446
Abstract
Mucormycosis is a rare, invasive fungal infection associated with high mortality. This retrospective study evaluated adult mucormycosis cases followed in our clinic between 2015 and 2025. A total of 13 patients were included, with a mean age of 50.92 ± 20.65 years (range, [...] Read more.
Mucormycosis is a rare, invasive fungal infection associated with high mortality. This retrospective study evaluated adult mucormycosis cases followed in our clinic between 2015 and 2025. A total of 13 patients were included, with a mean age of 50.92 ± 20.65 years (range, 20–83), and 10 (76.9%) were male. The most frequent symptom was facial pain (100%). Four (30.8%) of the patients had rhino-sinusitis, and three (23%) had rhino-orbito-cerebral involvement. Seven (53.9%) of the patients had hematological malignancy, three (23%) had diabetes mellitus (DM), two (15.4%) had a history of COVID-19 pneumonia, and one (7.7%) had a history of both DM and COVID-19 pneumonia. All had elevated C-reactive protein levels. Rhizopus spp. grew in nasal/tissue cultures of three (23%) patients, and so did Mucor spp. Surgery was performed in 11 (84.6%) patients, and fungal hyphae were observed in tissue histopathology. All patients showed radiological findings of mucormycosis on imaging. All patients received Liposomal Amphotericin B, and nine (69.2%) patients received sequential posaconazole therapy. Recurrence occurred in two (15.4%) patients. A total of eight (61.5%) patients, including three (23%) patients with intracranial involvement, died. Mucormycosis is a severe infection, especially in patients with hematological malignancies or DM, despite early diagnosis and combined antifungal and surgical treatments. Full article
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17 pages, 2572 KB  
Article
Territorial Persistence of Residual Plasmodium falciparum Transmission in the Americas: A One Health Perspective
by Mario J. Olivera
Trop. Med. Infect. Dis. 2026, 11(6), 151; https://doi.org/10.3390/tropicalmed11060151 - 31 May 2026
Viewed by 446
Abstract
Malaria reduction in the Americas has slowed despite sustained elimination efforts, suggesting important changes in the spatial organization of residual transmission. This study evaluated whether declining Plasmodium falciparum incidence between 2000 and 2023 was associated with increasing geographic concentration, spatial clustering, and territorial [...] Read more.
Malaria reduction in the Americas has slowed despite sustained elimination efforts, suggesting important changes in the spatial organization of residual transmission. This study evaluated whether declining Plasmodium falciparum incidence between 2000 and 2023 was associated with increasing geographic concentration, spatial clustering, and territorial persistence across the region, with detailed subnational analysis in Colombia. Temporal trends were assessed using segmented regression, geographic concentration using Gini and Herfindahl–Hirschman indices, and spatial dependence using Moran’s I and local indicators of spatial association. A Municipal Persistence Index (MPI) was developed to identify municipalities characterized by recurrent high transmission over time. Regional incidence declined by 62.7% but showed progressive temporal deceleration, while more than 80% of cumulative burden remained concentrated in four countries. Since 2020, Colombia has contributed nearly 40% of all reported P. falciparum cases in the Americas. Within Colombia, high-persistence municipalities largely overlapped with statistically significant spatial clusters concentrated along the Pacific region. These findings suggest that residual P. falciparum transmission is increasingly organized into territorially structured persistence systems rather than diffuse endemicity. Advancing malaria elimination may therefore require territorially coordinated One Health strategies aligned with the spatial organization of residual transmission. Full article
(This article belongs to the Special Issue One Health Approach to Malaria Elimination)
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15 pages, 962 KB  
Article
Serological Susceptibility to Measles Among International Students in South Korea After a Cluster of Cases: A Cross-Sectional Study
by Minyu Qin, Na Young Hong, Shin Woo Kim, Ji Hyuk Park, Seok Ju Yoo, Sung Jun Park, Younjoo Kim, Sang Yun Cho, Sook Hee Park, Hyun Jun Kang, Byeong Ryeon Kim, Mina Lee, Hyejin Hong, Minjei Lee, Myung Jae Hwang, Sookhyun Kim, Myung Hee Kim, Min A. Lim, Youkyoung Kim and Kwan Lee
Trop. Med. Infect. Dis. 2026, 11(6), 150; https://doi.org/10.3390/tropicalmed11060150 - 30 May 2026
Viewed by 286
Abstract
Background: Even though South Korea had eliminated measles in 2006, a localized cluster of measles occurred in a university dormitory in Gyeongsangbuk-do, South Korea, in 2024, involving 22 international students. This study aims to explore measles transmission and to inform future preventive measures. [...] Read more.
Background: Even though South Korea had eliminated measles in 2006, a localized cluster of measles occurred in a university dormitory in Gyeongsangbuk-do, South Korea, in 2024, involving 22 international students. This study aims to explore measles transmission and to inform future preventive measures. Methods: In a cross-sectional study, 299 international students from two local universities underwent a self-reported questionnaire survey and targeted serological testing by enzyme-linked immunosorbent assay two months after the cluster of measles cases. Statistical analysis used Pearson’s chi-square test, Fisher’s exact test, multivariate logistic regression, and Firth’s penalized logistic regression. Results: The overall seropositivity was 79.6%, and 78.0% among participants aged ≤30 years. Among multivariate analyses, nationality was independently associated with seropositivity (aOR up to 8.35 for Chinese students). Conclusions: These findings underscore the immunity gaps among international students, with seropositivity remaining below the 95% threshold required for herd immunity. Targeted serological screening and catch-up vaccination may help to improve immunity in mobile populations. Full article
(This article belongs to the Section Infectious Diseases)
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22 pages, 680 KB  
Article
Knowledge, Attitudes, Practices, and Information Pathways Related to Brucellosis Among Adults in Najran City, Saudi Arabia: A Stratified Time–Location Cross-Sectional Study
by Abdullateef Abdullah Alshehri, Mohammad Y. Alqahtani, Osman AE. Elnoubi, Mohsen A. Qahtani, Dehiyyan E. Alyami, Meshal M. Alabbas, Mosa M. Bahnass, Abdullah Alshehari, Mohammed A. Alshehri and Mohammed A. Alshahrani
Trop. Med. Infect. Dis. 2026, 11(6), 149; https://doi.org/10.3390/tropicalmed11060149 - 29 May 2026
Viewed by 435
Abstract
Brucellosis remains an important zoonotic disease in southern Saudi Arabia; however, community-level knowledge, risk-related practices, and information pathways in Najran City are insufficiently characterized. This study assessed brucellosis-related knowledge, attitudes, practices, and information pathways among adults in Najran City to inform locally relevant [...] Read more.
Brucellosis remains an important zoonotic disease in southern Saudi Arabia; however, community-level knowledge, risk-related practices, and information pathways in Najran City are insufficiently characterized. This study assessed brucellosis-related knowledge, attitudes, practices, and information pathways among adults in Najran City to inform locally relevant One Health interventions. In this cross-sectional survey, adults were recruited using stratified time–location (venue-based) sampling across community and exposure-relevant sites in Najran City. A total of 608 adults completed a structured interviewer-administered questionnaire. Composite scores were calculated for knowledge (0–21), attitude (0–22), practice (0–64), and information-source breadth (0–6). Descriptive statistics, group comparisons, correlation analyses, and multivariable linear regressions were performed. The findings suggest that participants more commonly relied on interpersonal social networks, especially family and friends, for information related to brucellosis (53.9%), whereas formal sources were less commonly reported, including health professionals (7.9%), media (4.6%), internet sources (3.3%), educational institutions (2.0%), and agricultural or veterinary organizations (1.3%). Mean knowledge scores were moderate (10.7/21), attitudes were generally favorable (19.5/22), and practice scores were moderate (36.6/64). Exposure-related behaviors remained common, particularly the consumption of unpasteurized milk or dairy products (56.6%). The breadth of information sources showed a moderate positive correlation with knowledge (rho = 0.561), whereas attitude showed only small positive correlations with knowledge and practice. Finally, knowledge was weakly and inversely correlated with practice. Among adults recruited in this venue-based sample, favorable attitudes did not consistently correspond to safer practices. These findings support practical One Health interventions, including coordinated veterinary–public health messaging on animal abortion events, safe-dairy guidance at points of sale and community venues, workplace-based training for livestock-contact groups, and referral pathways linking suspected animal cases with veterinary services and human care-seeking. Because recruitment was venue-based and non-probability, the results should be interpreted as descriptive and hypothesis-generating rather than population-representative; however, they still identify practical communication and service-delivery priorities for future intervention studies in Najran. Full article
(This article belongs to the Special Issue Advances in Brucella Infections)
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15 pages, 1495 KB  
Brief Report
Schistosoma japonicum Worms Alter the miRNA Expression Profile of Hepatic Stellate Cells with Potential Implications for Liver Fibrosis and Hepatocellular Carcinoma
by Haoran Zhong, Bowen Dong, Danlin Zhu, Ruiting Zhang, Yuanzhao Sun, Junhan Xiong, Liu Gao, Ke Lu, Hao Li, Zhiqiang Fu, Jinming Liu and Yamei Jin
Trop. Med. Infect. Dis. 2026, 11(6), 148; https://doi.org/10.3390/tropicalmed11060148 - 28 May 2026
Viewed by 348
Abstract
Although schistosome eggs are widely recognized as the principal drivers of hepatic granulomatous inflammation and fibrosis, the independent effects of adult worms may be masked by strong egg antigen-mediated responses. This study aimed to investigate whether adult Schistosoma japonicum worms alter the miRNA [...] Read more.
Although schistosome eggs are widely recognized as the principal drivers of hepatic granulomatous inflammation and fibrosis, the independent effects of adult worms may be masked by strong egg antigen-mediated responses. This study aimed to investigate whether adult Schistosoma japonicum worms alter the miRNA expression profile of hepatic stellate cells and to explore the potential relevance of these changes to liver fibrosis and hepatocellular carcinoma-related processes. A non-contact Transwell co-culture system was established using paired Schistosoma japonicum worms or male worms and hepatic stellate cells. Male worms were additionally included to further assess worm-derived effects independent of egg production–related influences. Untreated hepatic stellate cells served as controls. Total RNA was extracted for miRNA sequencing, and differentially expressed miRNAs were identified. Target gene prediction, Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis, and validation using The Cancer Genome Atlas database were subsequently performed. Both paired worms and male worms significantly altered the miRNA expression profile of hepatic stellate cells. Several differentially expressed miRNAs were identified, among which hsa-miR-103a-3p showed relatively stable changes. Pathway enrichment analysis suggested that the potential target genes of hsa-miR-103a-3p were mainly enriched in AMP-activated protein kinase, mechanistic target of rapamycin, tumor necrosis factor, insulin signaling, and cellular senescence pathways. Further analysis using The Cancer Genome Atlas database showed that hsa-miR-103a-3p had diagnostic value in hepatocellular carcinoma and was associated with alpha-fetoprotein level, albumin level, Ishak fibrosis score, pathological stage, histological type, and tumor status. These findings suggest that adult S. japonicum worms may alter the miRNA expression profile of hepatic stellate cells, and that hsa-miR-103a-3p may be associated with fibrogenic responses and may have potential relevance to hepatocellular carcinoma-related processes. However, this inference is based on correlative TCGA data and does not imply a causal role in schistosomiasis-associated hepatocarcinogenesis. Full article
(This article belongs to the Special Issue Research Advances and New Perspectives on Helminthic Diseases)
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20 pages, 1788 KB  
Article
Residual Human Intestinal Nematode Infections Following Discontinuation of Mass Drug Administration in a Rural South Asian Setting: Implications for Deworming Surveillance
by Nalini Jayakody, Catherine A. Gordon, Anjana Silva, Nuwan Wickramasinghe, Susiji Wickramasinghe, Natasha Collinson, Asela Wijayasekara, Chanaka Karunarathne, Nilanthi de Silva and Kosala Weerakoon
Trop. Med. Infect. Dis. 2026, 11(6), 147; https://doi.org/10.3390/tropicalmed11060147 - 27 May 2026
Viewed by 466
Abstract
Prevalence of soil-transmitted helminth (STH) infections in Sri Lanka has declined from 73.3% in 1954 to <1% in 2017, leading to revised deworming policies and discontinuation of routine deworming in three districts, including Anuradhapura, in 2019. As countries approach elimination, this study assessed [...] Read more.
Prevalence of soil-transmitted helminth (STH) infections in Sri Lanka has declined from 73.3% in 1954 to <1% in 2017, leading to revised deworming policies and discontinuation of routine deworming in three districts, including Anuradhapura, in 2019. As countries approach elimination, this study assessed human intestinal nematode infection (HINI) prevalence in Anuradhapura, a low-endemic setting, using microscopic and molecular methods. From January to November 2023, 967 primary school children were recruited and screened for HINI using direct smears, Kato–Katz, formalin ether concentration, agar plate culture, scotch tape, and qPCR. Combined microscopy and molecular prevalence was 41.2% for STH and 54.1% for HINI. The most prevalent HINI was Enterobius vermicularis (191, 24.5%), followed by Strongyloides stercoralis (120, 19.2%), Ascaris lumbricoides (113, 18.1%), Trichuris trichiura (40, 6.4%), and hookworm (43, 6.9%). Against the composite reference standard, qPCR demonstrated superior diagnostic performance across all species, achieving sensitivities of 86.7% for Ascaris, 85.0% for Trichuris, and 97.7% for hookworm, consistently exceeding those of microscopy-based methods. Correspondingly, qPCR also identified the highest infection prevalences, detecting Ascaris, Trichuris, and hookworm infections in 15.7%, 5.4%, and 6.7% of participants, respectively. All infections were low-intensity as determined by Kato–Katz. Microscopy significantly underestimates STH prevalence. In post-deworming settings, integrated surveillance including molecular diagnostics is essential. The high prevalence of S. stercoralis and E. vermicularis highlights the need for expanded surveillance and targeted interventions to support sustainable control. Full article
(This article belongs to the Section Neglected and Emerging Tropical Diseases)
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16 pages, 4847 KB  
Article
Localization of the Complement C1q-Binding Site on Echinococcus multilocularis Calreticulin Identified by Peptide Mapping
by Yinghui Song, Meng Xia, Haoran Zong, Wenjie Dong, Qiang Wang, Qin Yang, Bin Zhan, Yanhai Wang and Limei Zhao
Trop. Med. Infect. Dis. 2026, 11(6), 146; https://doi.org/10.3390/tropicalmed11060146 - 26 May 2026
Viewed by 457
Abstract
Alveolar echinococcosis is a life-threatening zoonotic parasitic disease caused by infection of Echinococcus multilocularis larvae. To survive within the host’s immune milieu, E. multilocularis has evolved sophisticated immune evasion strategies, including the expression of immunomodulatory proteins that regulate the host immune response. Our [...] Read more.
Alveolar echinococcosis is a life-threatening zoonotic parasitic disease caused by infection of Echinococcus multilocularis larvae. To survive within the host’s immune milieu, E. multilocularis has evolved sophisticated immune evasion strategies, including the expression of immunomodulatory proteins that regulate the host immune response. Our previous studies have demonstrated that E. multilocularis calreticulin (EmCRT) possessed strong binding ability to human complement component C1q to inhibit C1q-initiated complement activation and biological functions. To further elucidate the mechanism by which EmCRT mediates C1q inactivation and immune evasion, the precise C1q-binding site on EmCRT was identified and analyzed in this study through expression of overlapping fragments and synthesis of overlapping peptides covering the identified functional fragment. The fragment expression and functional assay narrowed down the C1q-binding site to the EmCRT-S1 fragment located between amino acids 140 and 204 of EmCRT. The precise binding site was further pinpointed to the P5 peptide (EmCRT160–174 aa) by testing the synthetic peptides covering this region. The binding of peptide P5 to C1q markedly suppressed the activation of the C1q-mediated classical complement pathway and C1q-induced neutrophil chemotaxis, production of reactive oxygen species, cathepsin G, and myeloperoxidase. These findings suggest that the C1q-binding P5 peptide of EmCRT may serve as a potential target for the development of vaccines against echinococcosis or therapeutic drugs for complement-associated inflammatory or autoimmune diseases. Full article
(This article belongs to the Special Issue Research Advances and New Perspectives on Helminthic Diseases)
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9 pages, 667 KB  
Brief Report
High Positivity Rate for Leptospira Infection in Symptomatic Urban Owned Dogs in Guayaquil, Ecuador
by Solon Alberto Orlando, Naomi Mora Jaramillo, Ariana Montenegro Pesántez, Melissa Joseth Carvajal-Capa, Jose Julián Zuñiga-Velarde, Silvia Tafur and Miguel Angel Garcia-Bereguiain
Trop. Med. Infect. Dis. 2026, 11(6), 145; https://doi.org/10.3390/tropicalmed11060145 - 26 May 2026
Viewed by 416
Abstract
Leptospirosis is a zoonotic disease caused by spirochete bacteria of the genus Leptospira, with a wide global distribution. In Ecuador, leptospirosis is endemic, particularly in low-resource tropical areas, and multiple animal reservoirs have been identified either in rural or urban areas, including [...] Read more.
Leptospirosis is a zoonotic disease caused by spirochete bacteria of the genus Leptospira, with a wide global distribution. In Ecuador, leptospirosis is endemic, particularly in low-resource tropical areas, and multiple animal reservoirs have been identified either in rural or urban areas, including stray dogs. In this study, a total of 81 domestic dogs presenting clinical manifestations compatible with leptospirosis were recruited at the Municipal Center for Animal Welfare in Guayaquil, Ecuador, in 2023. A survey regarding clinical, demographic, and environmental risk factors was filled in by every dog’s owner; urine and blood samples were collected for pathogenic Leptospira diagnosis by qPCR for lipL32, rrs, and secY gene targets. A very high (62.96%) positivity rate for Leptospira infection was found. Almost 90% of the dogs were not vaccinated against Leptospira. Although the animals exhibited multiple clinical signs, none showed a statistically significant association with Leptospira positivity, confirming the nonspecific presentation of the disease and its potential for misdiagnosis. The consumption of bulk food emerged as a significant environmental risk factor only in the multivariate logistic regression and not in the univariate analysis, suggesting the need for improved food safety practices. Moreover, we reported very frequent close-contact behaviors between owners and dogs. Overall, our study underscores the potential role of owned urban dogs as reservoirs of Leptospira in the city of Guayaquil in Ecuador, emphasizing the need for public health policies to increase awareness and improve diagnosis in domestic animals under a comprehensive One Health vision. Full article
(This article belongs to the Special Issue Leptospirosis and One Health)
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26 pages, 3327 KB  
Article
Zoonotic Spillover of a Canine-like Rotavirus A G3P[3] Strain in a Brazilian Child
by Vanessa Cristina Martins Silva, Lais Sampaio Azevedo, Raquel Guiducci and Adriana Luchs
Trop. Med. Infect. Dis. 2026, 11(6), 144; https://doi.org/10.3390/tropicalmed11060144 - 26 May 2026
Viewed by 396
Abstract
Rotavirus A (RVA) G3P[3] genotype is widely reported in dogs and less frequently in cats, with only sporadic human cases worldwide. All reported human infections have occurred in children, suggesting increased susceptibility likely linked to close contact with pets and age-related hygiene practices. [...] Read more.
Rotavirus A (RVA) G3P[3] genotype is widely reported in dogs and less frequently in cats, with only sporadic human cases worldwide. All reported human infections have occurred in children, suggesting increased susceptibility likely linked to close contact with pets and age-related hygiene practices. The identification of a novel genotype constellation in Brazilian canine G3P[3] strains in 2017 prompted full-genotype characterization of the historical RVA/Human-wt/BRA/IAL-R451/2011/G3P[3] strain, previously sequenced only for VP7 and VP4, to define its genomic constellation and relatedness to canine strains. All 11 segments were analyzed by RT-PCR, sequencing and phylogenetics. The rare genotype–lineage constellation G3.III-P[3]-I2.XX-R3.II-C2.V-M3.II-A9-N2.XXIV-T3.II-E3.II-H6.I, shared with Brazilian canine strains, was identified, supporting a potential common origin. RVA/Human-wt/BRA/IAL-R451/2011/G3P[3] strain showed high genetic similarity (93.2–99%) with canine, feline and canine/feline-like human strains worldwide, with six genes (VP1, VP6 and NSP2–NSP5) closely related to Brazilian dog isolates (97.6–99%), indicating its canine origin. NSP2 clustered with strains from domestic (bovine), synanthropic (rat) and human hosts, while VP7 and VP4 were associated with wildlife (bat; raccoon dog) and environmental (sewage; river water) strains, supporting interhost reassortment and highlighting aquatic environments as reservoirs for interspecies transmission. Identification of new lineages (VP1, VP3 and NSP2) within the AU-1-like backbone reflects its underexplored diversity. This novel constellation likely circulated in dogs and may spill over to humans via close contact, reinforcing a One Health approach to understand RVA zoonotic risk, especially in hotspot regions like Brazil. Full article
(This article belongs to the Special Issue Viral Enteropathogens in Pediatric Populations)
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14 pages, 1402 KB  
Article
Anthropophagy and Ecological Bridges: Blood-Meal Patterns of Invasive Aedes albopictus (Skuse, 1894) and Native Aedes aegypti Linnaeus, 1762 and Their Implications for Arbovirus Emergence in Central Africa
by Armel N. Tedjou, Christophe R. Keumeni, Aurélie P. Yougang, Flobert Njiokou, Jo Lines, Sian E. Clarke, Charles S. Wondji and Basile Kamgang
Trop. Med. Infect. Dis. 2026, 11(6), 143; https://doi.org/10.3390/tropicalmed11060143 - 25 May 2026
Viewed by 629
Abstract
Aedes (Ae.) aegypti and Ae. albopictus are important vectors of arboviruses. Yet their blood-feeding pattern remains poorly characterised in Africa, including Cameroon. In this study, we characterised the blood-meal sources in both species collected from vegetation, household surroundings, and animal cages across four [...] Read more.
Aedes (Ae.) aegypti and Ae. albopictus are important vectors of arboviruses. Yet their blood-feeding pattern remains poorly characterised in Africa, including Cameroon. In this study, we characterised the blood-meal sources in both species collected from vegetation, household surroundings, and animal cages across four urban sites, one rural site, and a zoo-botanical garden where humans and animals in captivity are the main hosts. Overall, Aedes mosquitoes represented about half of 10,054 female mosquitoes collected, with Ae. albopictus strongly dominating Ae. aegypti among 5001 Aedes females, and only 5.95% of females visibly blood-fed. Sequencing a 748 base pairs (bp) fragment of the cytochrome oxidase I gene from 156 blood-fed abdomens yielded 126 high-confidence host assignments, of which 98.25% were humans, indicating a strong anthropophagic pattern in both species. Unpredictably, two Ae. albopictus individuals had fed on a baboon (Papio anubis) and a frugivorous bat (Pteropodidae), as confirmed by bio informatic analyses, highlighting the species’ opportunistic blood-feeding nature and providing preliminary molecular evidence consistent with a potential bridge-vector role in this setting. Despite the extreme anthropophagy of both species observed, results indicate that Ae. albopictus could also serve as a bridge vector enabling spillover of enzootic viruses to humans, including urbanised settings where wild animals are present. These findings emphasise the urgent need for enhanced arbovirus surveillance in Central Africa using a One Health approach. Full article
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