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Trop. Med. Infect. Dis., Volume 11, Issue 1 (January 2026) – 33 articles

Cover Story (view full-size image): Leptospirosis is a major public health and economic burden in Southeast Asia, driven by human–animal contact, poor socioeconomic conditions, and climate factors. Disease burden estimates are hindered by variable seroprevalence, inconsistent diagnostics, and weak surveillance systems, leading to underdiagnosis and delayed treatment. Diagnostic tools are often unsuitable for resource-limited settings, and environmental modeling is underutilized due to poor data integration. A One Health approach incorporating key actions such as harmonized surveillance, standardized diagnostics, vaccination, and improved animal husbandry is recommended. Public education, urban infrastructure upgrades, early warning systems, stronger governance, and research investment are also needed to sustainably reduce transmission. View this paper
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2 pages, 135 KB  
Editorial
Insecticide Resistance and Vector Control
by Adriana E. Flores, Jesus A. Davila-Barboza and Alan E. Juache-Villagrana
Trop. Med. Infect. Dis. 2026, 11(1), 33; https://doi.org/10.3390/tropicalmed11010033 - 22 Jan 2026
Viewed by 277
Abstract
Insecticide-based strategies have been central to vector control programs targeting diseases of human and veterinary importance for decades [...] Full article
(This article belongs to the Special Issue Insecticide Resistance and Vector Control)
4 pages, 598 KB  
Reply
Reply to Wüster et al. On the Importance of Correct Snake Identification. Comment on “Chippaux et al. Snakebites in Cameroon by Species Whose Effects Are Poorly Described. Trop. Med. Infect. Dis. 2024, 9, 300”
by Jean-Philippe Chippaux and Fabien Taieb
Trop. Med. Infect. Dis. 2026, 11(1), 32; https://doi.org/10.3390/tropicalmed11010032 - 22 Jan 2026
Viewed by 162
Abstract
As Wüster et al [...] Full article
(This article belongs to the Special Issue Snake Bite: Prevention, Diagnosis and Treatment)
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5 pages, 411 KB  
Comment
On the Importance of Correct Snake Identification. Comment on Chippaux et al. Snakebites in Cameroon by Species Whose Effects Are Poorly Described. Trop. Med. Infect. Dis. 2024, 9, 300
by Wolfgang Wüster, David A. Warrell and David J. Williams
Trop. Med. Infect. Dis. 2026, 11(1), 31; https://doi.org/10.3390/tropicalmed11010031 - 22 Jan 2026
Cited by 1 | Viewed by 334
Abstract
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 [...] Full article
(This article belongs to the Special Issue Snake Bite: Prevention, Diagnosis and Treatment)
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11 pages, 700 KB  
Article
Epidemiological Characteristics of Human Rabies in Chongqing, China, 2016–2024
by Longyu Chen, Yi Yuan, Yu Xia, Jiang Long, Zhijin Li, Tingting Li and Li Qi
Trop. Med. Infect. Dis. 2026, 11(1), 30; https://doi.org/10.3390/tropicalmed11010030 - 22 Jan 2026
Viewed by 503
Abstract
(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 [...] Read more.
(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. Full article
(This article belongs to the Special Issue Rabies Epidemiology, Control and Prevention Studies)
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4 pages, 179 KB  
Editorial
Beyond Borders—Tackling Neglected Tropical Viral Diseases
by Jelena Prpić
Trop. Med. Infect. Dis. 2026, 11(1), 29; https://doi.org/10.3390/tropicalmed11010029 - 21 Jan 2026
Viewed by 265
Abstract
Neglected tropical diseases (NTDs) comprise a diverse group of infections that disproportionately affect impoverished populations in tropical and subtropical regions [...] Full article
(This article belongs to the Special Issue Beyond Borders—Tackling Neglected Tropical Viral Diseases)
22 pages, 1243 KB  
Review
Global Lymphatic Filariasis Post-Validation Surveillance Activities in 2025: A Scoping Review
by Holly Jian, Harriet Lawford, Angus McLure, Colleen Lau and Adam Craig
Trop. Med. Infect. Dis. 2026, 11(1), 28; https://doi.org/10.3390/tropicalmed11010028 - 19 Jan 2026
Viewed by 576
Abstract
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 [...] Read more.
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. Full article
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17 pages, 1227 KB  
Article
Barriers and Facilitators to Implementing Post-Validation Surveillance of Lymphatic Filariasis in Pacific Island Countries and Territories: A Conceptual Framework Developed from Qualitative Data
by 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 and Adam T. Craig
Trop. Med. Infect. Dis. 2026, 11(1), 27; https://doi.org/10.3390/tropicalmed11010027 - 18 Jan 2026
Cited by 1 | Viewed by 335
Abstract
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 [...] Read more.
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. Full article
(This article belongs to the Section Neglected and Emerging Tropical Diseases)
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20 pages, 2320 KB  
Article
A Non-Inferiority Evaluation of YAHE 4.0, an Alphacypermethrin-PBO Insecticide-Treated Net Against Pyrethroid Resistant Anopheles arabiensis in Experimental Huts in Moshi, North-Eastern Tanzania
by 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 and Franklin Moshaadd Show full author list remove Hide full author list
Trop. Med. Infect. Dis. 2026, 11(1), 26; https://doi.org/10.3390/tropicalmed11010026 - 18 Jan 2026
Viewed by 405
Abstract
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 [...] Read more.
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. Full article
(This article belongs to the Special Issue Insecticide Resistance and Vector Control)
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14 pages, 1269 KB  
Article
Schistosomiasis in Saudi Arabia (2002–2024): A National Analysis of Trends, Regional Heterogeneity, and Progress Toward Elimination
by Yasir Alruwaili
Trop. Med. Infect. Dis. 2026, 11(1), 25; https://doi.org/10.3390/tropicalmed11010025 - 16 Jan 2026
Viewed by 335
Abstract
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. [...] Read more.
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. Full article
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11 pages, 992 KB  
Article
Updating the Endemicity Map of Soil-Transmitted Helminthiasis in Ten Local Government Areas of Ondo State, Southwestern Nigeria
by 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 and Louise K. Makau-Barasa
Trop. Med. Infect. Dis. 2026, 11(1), 24; https://doi.org/10.3390/tropicalmed11010024 - 14 Jan 2026
Viewed by 375
Abstract
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 [...] Read more.
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. Full article
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12 pages, 1194 KB  
Article
Strengthening the National Reference Laboratory in the Republic of Congo: An Investment Imperative for Tuberculosis Diagnostics
by 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 and Dissou Affolabi
Trop. Med. Infect. Dis. 2026, 11(1), 23; https://doi.org/10.3390/tropicalmed11010023 - 13 Jan 2026
Cited by 1 | Viewed by 513
Abstract
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 [...] Read more.
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. Full article
(This article belongs to the Special Issue Tuberculosis Diagnosis: Current, Ongoing and Future Approaches)
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16 pages, 2757 KB  
Article
Analysis of the Short- and Long-Term Immune Response in BALB/c Mice Immunized with Total Naegleria fowleri Extract Co-Administered with Cholera Toxin
by Mara Gutiérrez-Sánchez, Maria de la Luz Ortega-Juárez, María Maricela Carrasco-Yépez, Rubén Armando Herrera-Ceja, Itzel Berenice Rodríguez-Mera and Saúl Rojas-Hernández
Trop. Med. Infect. Dis. 2026, 11(1), 22; https://doi.org/10.3390/tropicalmed11010022 - 12 Jan 2026
Viewed by 259
Abstract
Background: Naegleria fowleri is a free-living amoeba that inhabits warm freshwater and causes primary amoebic meningoencephalitis (PAM), a rapidly fatal infection with >95% mortality. Due to the lack of early diagnosis and effective therapy, preventive vaccination represents a promising strategy. Methods: This study [...] Read more.
Background: Naegleria fowleri is a free-living amoeba that inhabits warm freshwater and causes primary amoebic meningoencephalitis (PAM), a rapidly fatal infection with >95% mortality. Due to the lack of early diagnosis and effective therapy, preventive vaccination represents a promising strategy. Methods: This study evaluated short- and long-term immune protection in BALB/c mice (20 mice per group) immunized intranasally with total N. fowleri extract co-administered with cholera toxin (CT). Mice were challenged with a lethal dose of trophozoites either 24 h (short-term) or three months (long-term) after the fourth immunization; the latter group received a booster 24 h before challenge. Serum and nasal washes were analyzed for IgA and IgG antibodies by immunoblot, and lymphocyte subsets from nasal-associated lymphoid tissue (NALT) and nasal passages (NPs) were characterized by flow cytometry. Results: Immunization conferred complete (100%) survival in the 24 h group and 60% protection in the 3-month group, whereas all control mice died. Immunoblotting showed that IgA and IgG antibodies recognized major N. fowleri antigens of 37, 45, 48 and 19, 37, and 100 kDa, respectively. Flow cytometry revealed increased activated and memory B lymphocytes, dendritic cells, and expression of CCR10, integrin α4β1, and FcγRIIB receptors, particularly in the 24 h group. Conclusions: Intranasal immunization with N. fowleri extract plus CT elicited both systemic and mucosal immune responses capable of short- and long-term protection. These findings highlight the potential of this immunization strategy as a foundation for developing effective vaccines against PAM. Full article
(This article belongs to the Special Issue Naegleria fowleri and Emerging Amoebic Infections)
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18 pages, 4818 KB  
Article
Temporal Trends in Lower Respiratory Infection Mortality in Ecuador, 2012–2022
by Reena Krishna, Luis Furuya-Kanamori and Harriet L. S. Lawford
Trop. Med. Infect. Dis. 2026, 11(1), 21; https://doi.org/10.3390/tropicalmed11010021 - 12 Jan 2026
Viewed by 361
Abstract
Lower respiratory infections (LRIs) are responsible for significant morbidity and mortality in Ecuador; however, evidence to support prevention strategies is limited. This study aimed to identify age-specific trends, spatial patterns, and sociodemographic risk factors of LRI mortality in Ecuador between 2012–2022, utilizing national [...] Read more.
Lower respiratory infections (LRIs) are responsible for significant morbidity and mortality in Ecuador; however, evidence to support prevention strategies is limited. This study aimed to identify age-specific trends, spatial patterns, and sociodemographic risk factors of LRI mortality in Ecuador between 2012–2022, utilizing national mortality data sourced from the Ecuadorian National Institute for Statistics and Censuses (INEC). Age-sex-specific trend analysis was performed using Joinpoint regression. LRI age-standardized mortality rates (ASMRs) were mapped by province of death, and percentage change was calculated between 2012 and 2019. Multivariable logistic regression was performed to assess risk factors pre- and post-2020. A change in trend in LRI mortality rate, from a decreasing trend to a marginal increasing trend, was identified for both genders in children aged 0–4 and 5–15 years. There were significant increasing trends for males (2014–2019 APC: 2.21%, 95% CI: 0.57, 6.70) and females (2016–2019 APC: 4.62%, 95% CI: 0.84, 10.58) aged ≥ 70 years. From 2012 to 2019, the highest average LRI ASMR was in Guayas (30.90 deaths per 100,000 inhabitants), and the greatest percentage increase was observed in Orellana (419.54%). Before 2020, LRI mortality, compared to deaths of other causes, was significantly associated with sex, age, education, ethnicity, place of death and climate region, with major shifts post COVID-19 pandemic. Full article
(This article belongs to the Special Issue Respiratory Infectious Disease Epidemiology and Control)
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12 pages, 604 KB  
Article
Imported Eosinophilia in Migrants from Endemic Areas in Spain
by Laura Niño-Puerto, Belén Vicente, Juan Hernández-Goenaga, Javier Pardo Lledías, Juan Luis Muñoz Bellido, Moncef Belhassen-García and Antonio Muro
Trop. Med. Infect. Dis. 2026, 11(1), 20; https://doi.org/10.3390/tropicalmed11010020 - 11 Jan 2026
Viewed by 374
Abstract
Eosinophilia is a valuable biomarker for estimating the likelihood of parasitic infection in immigrants from tropical or subtropical regions. This study aimed to evaluate the frequency and etiology of imported eosinophilia in patients attending the Tropical Medicine Unit (TMU) of Salamanca, Spain, between [...] Read more.
Eosinophilia is a valuable biomarker for estimating the likelihood of parasitic infection in immigrants from tropical or subtropical regions. This study aimed to evaluate the frequency and etiology of imported eosinophilia in patients attending the Tropical Medicine Unit (TMU) of Salamanca, Spain, between 2008 and 2023. A total of 773 immigrant patients were assessed: 450 (58.2%) from Africa, 306 (39.6%) from Latin America, and 17 (2.2%) from Asia. Eosinophilia was observed in 338 patients (43.7%), of whom 15 (4.4%) had noninfectious causes. Among the remaining 323 evaluated for infections, 171 (52.9%) presented with relative eosinophilia and 152 (47.1%) presented with absolute eosinophilia. A specific diagnosis was reached in 49.2% of the cases, most commonly filariasis (12.1%), strongyloidiasis (9.9%), and schistosomiasis (4.6%): 58 patients had coinfections. In conclusion, eosinophilia is common among migrants and represents a valuable biomarker for helminthiasis. Despite protocolized evaluation, nearly half of the cases remain undiagnosed. The most frequent etiologies were filariasis, strongyloidiasis, and schistosomiasis, with African patients having the highest probability of diagnosis. Improved diagnostic approaches, including tests for less common parasites, may reduce uncertainty and enhance clinical management. Full article
(This article belongs to the Section Travel Medicine)
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26 pages, 3397 KB  
Article
The Effect of Artemether–Lumefantrine Combined with a Single Dose of Primaquine on Plasmodium falciparum Gametocyte Clearance and Post-Treatment Infectivity to Anopheles arabiensis
by Awoke Minwuyelet, Delenasaw Yewhalaw, Giulio Petronio Petronio, Roberto Di Marco and Getnet Atenafu
Trop. Med. Infect. Dis. 2026, 11(1), 19; https://doi.org/10.3390/tropicalmed11010019 - 8 Jan 2026
Viewed by 715
Abstract
Background: Malaria remains a major public health concern in Africa, due to the persistence of Plasmodium falciparum gametocytes that sustain transmission post treatment. This study evaluated the effects of artemether–lumefantrine (AL) alone compared with AL combined with a single low-dose of primaquine (SLD-PQ) [...] Read more.
Background: Malaria remains a major public health concern in Africa, due to the persistence of Plasmodium falciparum gametocytes that sustain transmission post treatment. This study evaluated the effects of artemether–lumefantrine (AL) alone compared with AL combined with a single low-dose of primaquine (SLD-PQ) on gametocyte clearance and infectivity to Anopheles arabiensis post treatment. Methods: A prospective cohort and entomological study were conducted from January to September 2025 in Northwest Ethiopia. Ninety-six microscopically confirmed cases of P. falciparum gametocytemia mono-infection were proportionally assigned to both treatment groups. Follow-up assessments were conducted on days 3, 7, 14, and 28, and mixed-species infections were assessed using molecular diagnostic assays. Additionally, membrane feeding assays (MFAs) were performed to evaluate mosquito infectivity post treatment. Results: Gametocyte prevalence declined faster with AL + SLD-PQ (15.2% on day 3; 0% by day 7) compared to AL alone (28.9% on day 3: p = 0.001; 12.2% by day 7: p = 0.033). Higher baseline gametocyte density strongly predicted mosquito infection (95% in high vs. 59% moderate and 33% low). On day 3 post treatment, 28.6% of cases treated with AL only showed confirmed mosquito infection, compared to 6.8% in the AL + SLD-PQ group (p = 0.001). By day 7, 7.3% of cases remained infectious in the AL-only group, while none were detected in the AL+ SLD-PQ group (p = 0.01). Conclusions: High baseline gametocyte density strongly correlated with increased infectivity. Adding SLD-PQ markedly accelerates gametocyte clearance and completely blocks post-treatment transmission. Submicroscopic gametocytemia contributed to residual transmission in the AL-only group. Incorporation of SLD-PQ alongside AL, in line with WHO recommendations, is advised to enhance post-treatment transmission blocking, with continued surveillance. Full article
(This article belongs to the Section Infectious Diseases)
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34 pages, 894 KB  
Review
Leptospirosis in Southeast Asia: Investigating Seroprevalence, Transmission Patterns, and Diagnostic Challenges
by Chembie A. Almazar, Yvette B. Montala and Windell L. Rivera
Trop. Med. Infect. Dis. 2026, 11(1), 18; https://doi.org/10.3390/tropicalmed11010018 - 7 Jan 2026
Viewed by 1105
Abstract
Leptospirosis remains a significant public health and economic burden in Southeast Asia, particularly in low- and middle-income countries where environmental, occupational, and socioeconomic factors contribute to its endemicity. Transmission is driven by close interactions between humans and infected animal reservoirs, alongside climatic conditions [...] Read more.
Leptospirosis remains a significant public health and economic burden in Southeast Asia, particularly in low- and middle-income countries where environmental, occupational, and socioeconomic factors contribute to its endemicity. Transmission is driven by close interactions between humans and infected animal reservoirs, alongside climatic conditions such as heavy rainfall and flooding. The region’s high but variable seroprevalence reflects inconsistencies in diagnostic methodologies and surveillance systems, complicating disease burden estimation. Major gaps persist in diagnostic capabilities, with current tools often unsuitable for resource-limited settings, leading to underdiagnosis and delayed treatment. Environmental modeling and spatial epidemiology are underutilized due to limited interdisciplinary data integration and predictive capacity. Addressing these challenges requires a One Health approach that integrates human, animal, and environmental health sectors. Key policy recommendations include harmonized surveillance, standardized and validated diagnostics, expanded vaccination programs, improved animal husbandry, and targeted public education. Urban infrastructure improvements and early warning systems are also critical, particularly in disaster-prone areas. Strengthened governance, cross-sectoral collaboration, and investment in research and innovation are essential for sustainable leptospirosis control. Implementing these measures will enhance preparedness, reduce disease transmission, and contribute to improved public health outcomes in all sectors across the region. Full article
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10 pages, 2434 KB  
Article
Brucella, Coxiella, and Theileria Species DNA in Haemaphysalis qinghaiensis Ticks Collected from Goats and Sheep in Qinghai Province, Northwest China
by Kun Li, Xuxin Yang, Jianling Wang, Shengyu Li, Xu Zhao, Shengjun Cai, Leyu Wu, Guoqiang An, Hongyan Zhao, Dongri Piao, Qingqing Xu, Yu Fan, Jiquan Li and Hai Jiang
Trop. Med. Infect. Dis. 2026, 11(1), 17; https://doi.org/10.3390/tropicalmed11010017 - 7 Jan 2026
Viewed by 443
Abstract
Haemaphysalis qinghaiensis is an endemic tick species distributed in the western plateau areas of China. Although they are three-host ticks, infesting multiple animals (including humans), the occurrence of various tick-borne agents has barely been investigated. In this study, we collected 136 H. qinghaiensis [...] Read more.
Haemaphysalis qinghaiensis is an endemic tick species distributed in the western plateau areas of China. Although they are three-host ticks, infesting multiple animals (including humans), the occurrence of various tick-borne agents has barely been investigated. In this study, we collected 136 H. qinghaiensis specimens from sheep and goats in Menyuan County in Qinghai Province, northwest China. The Brucella, Coxiella, and Theileria/Babesia species’ DNA were detected by nested or hemi-nested PCR and further identified by amplifying their key genes. Brucella abortus and B. melitensis DNA were detected, with positive rates of 3.68% and 4.41%, respectively. This may be the first report that suggests that H. qinghaiensis harbors Brucella spp., the agents of human brucellosis. The Coxiella endosymbiont of Haemaphysalis qinghaiensis, a non-pathogenic Coxiella, was identified with an extremely high positive rate of 97.06%. In addition, two Theileria species, Theileria luwenshuni (75.00%) and Theileria uilenbergi (16.18%), were detected. Our results suggest the circulation of Brucella spp. and Theileria spp. in goats and sheep in the study area. Whether H. qinghaiensis ticks play a role in the maintenance and transmission of these agents has yet to be determined. Due to their human pathogenicity and their high positive rates in ticks, surveillance in local populations with relative symptoms is necessary. Full article
(This article belongs to the Special Issue The Distribution and Diversity of Tick-Borne Zoonotic Pathogens)
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13 pages, 1111 KB  
Article
Application of a One-Health Approach for Dermatophyte Infections
by Deborah Cruciani, Manuela Papini, Sara Spina, Carla Sebastiani, Vincenzo Piscioneri, Alessandro Fiorucci and Silvia Crotti
Trop. Med. Infect. Dis. 2026, 11(1), 16; https://doi.org/10.3390/tropicalmed11010016 - 6 Jan 2026
Viewed by 400
Abstract
Dermatomycoses pose significant zoonotic and public health challenges, involving interactions among fungal agents, host immunity, and environmental reservoirs. Eight cases of dermatophyte infection involving five humans, two cats and one dog were investigated in the Umbria region applying a One-Health approach, as recommended [...] Read more.
Dermatomycoses pose significant zoonotic and public health challenges, involving interactions among fungal agents, host immunity, and environmental reservoirs. Eight cases of dermatophyte infection involving five humans, two cats and one dog were investigated in the Umbria region applying a One-Health approach, as recommended by the CDC. Fungal isolates were identified by mycological and molecular methods as Microsporum canis (n = 4), Nannizzia gypsea (n = 3), and Trichophyton mentagrophytes var. mentagrophytes genotype III* (n = 1). The source of infection was identified in four cases enabling the implementation of appropriate treatment, removal of fomites, and environmental sanitization; as a result, no recurrences were observed. In the remaining cases, environmental assessments showed no fungal burden, indicating likely incidental transmission. Close cohabitation or contact with cats emerged as a risk factor. The patient’s medical history should always include exposure to animals in order to facilitate early recognition, correct management, and prevention. Interdisciplinary collaboration among dermatologists, veterinarians, and laboratory technicians is essential to optimize therapeutic outcomes and to prevent potential antifungal resistance phenomena. Moreover, continuous surveillance under a One-Health framework will enable better epidemiological understanding of dermatophyte species dynamics, particularly zoonotic agents. Full article
(This article belongs to the Special Issue Tackling Emerging Zoonotic Diseases with a One Health Approach)
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9 pages, 1205 KB  
Case Report
Alert for Imported Malaria in Non-Endemic Areas: A Case Report of Atypical Falciparum Malaria in a Young Child and Diagnostic Experience
by Jiali Feng, Yang Zhou, Bo Zhang and Ming Huang
Trop. Med. Infect. Dis. 2026, 11(1), 15; https://doi.org/10.3390/tropicalmed11010015 - 6 Jan 2026
Viewed by 562
Abstract
Background: Although China has eliminated indigenous malaria, imported cases, particularly among young and middle-aged workers returning from Africa, constitute a major challenge for current epidemic prevention and control. In contrast, imported malaria in children is extremely rare and often subject to diagnostic delays [...] Read more.
Background: Although China has eliminated indigenous malaria, imported cases, particularly among young and middle-aged workers returning from Africa, constitute a major challenge for current epidemic prevention and control. In contrast, imported malaria in children is extremely rare and often subject to diagnostic delays in non-endemic areas due to atypical clinical presentations. Case presentation: We report a case of a 2-year-11-month-old boy who returned from Sudan, a malaria-endemic region, presenting with fever and diarrhea as the initial symptoms. The case was identified by the laboratory through the blood routine re-examination rules, crucially informed by the patient’s epidemiological history. The diagnosis was ultimately confirmed as Plasmodium falciparum malaria by rapid diagnostic testing and microscopic examination. Conclusion: This diagnostic pathway exemplifies a closed-loop model of “clinical suspicion → targeted laboratory testing → definitive pathogen identification.” It provides a practical framework for the early detection and diagnosis of pediatric imported malaria with atypical presentations in non-endemic areas. Full article
(This article belongs to the Special Issue Advances in Tools for Battling Malaria)
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11 pages, 1029 KB  
Article
Occupational Infection Prevention Among Nurses and Laboratory Technicians Amidst Multiple Health Emergencies in Outbreak-Prone Country, D.R. Congo
by Nlandu Roger Ngatu, Sakiko Kanbara, Christian Wansu-Mapong, Daniel Kuezina Tonduangu, Ngombe Leon-Kabamba, Berthier Nsadi-Fwene, Bertin Mindje-Kolomba, Antoine Tshimpi, Kanae Kanda, Chisako Okai, Hiromi Suzuki, Nzaji Michel-Kabamba, Georges Balenda-Matondo, Nobuyuki Miyatake, Akira Nishiyama, Tomomi Kuwahara and Akihito Harusato
Trop. Med. Infect. Dis. 2026, 11(1), 14; https://doi.org/10.3390/tropicalmed11010014 - 2 Jan 2026
Viewed by 775
Abstract
Millions of healthcare workers experience percutaneous exposure to bloodborne communicable infectious disease pathogens annually, with the risk of contracting occupationally acquired infections. In this study, we aimed to assess the status of occupational safety and outbreak preparedness in Congolese nurses and laboratory technicians [...] Read more.
Millions of healthcare workers experience percutaneous exposure to bloodborne communicable infectious disease pathogens annually, with the risk of contracting occupationally acquired infections. In this study, we aimed to assess the status of occupational safety and outbreak preparedness in Congolese nurses and laboratory technicians in Kongo central and the Katanga area, amidst multiple ongoing public health emergencies in the Democratic Republic of the Congo (DRC). This was a multicenter analytical cross-sectional study conducted in five referral hospitals located in Kongo central province and the Katanga area between 2019 and 2020 amidst Ebola, Yellow fever, Cholera and Chikungunya outbreaks. Participants were adult A0 grade nurses, A1 nurses, A2 nurses and medical laboratory technicians (N = 493). They answered a structured, self-administered questionnaire related to hospital hygiene and standard precautions for occupational infection prevention. The majority of the respondents were females (53.6%), and 30.1% of them have never participated in a training session on hospital infection prevention during their career. The proportions of those who have been immunized against hepatitis B virus (HBV) was markedly low, at 16.5%. Of the respondents, 75.3% have been using safety-engineered medical devices (SEDs), whereas 93.5% consistently disinfected medical devices after use. Moreover, 78% of the respondents used gloves during medical procedures and 92.2% wore masks consistently. A large majority of the respondents, 82.9%, have been recapping the needles after use. Regarding participation in outbreak response, 24.5% and 12.2% of the respondents were Chikungunya and Cholera epidemic responders, respectively; 1.8% have served in Ebola outbreak sites. The proportion of the respondents who sustained at least one percutaneous injury by needlestick or sharp device, blood/body fluid splash or both in the previous 12-month period was high, 89.3% (41.8% for injury, 59.2% for BBF event), and most of them (73%) reported over 11 events. Compared to laboratory technicians, nurses had higher odds for sustaining percutaneous injury and BBF events [OR = 1.38 (0.16); p < 0.01], whereas respondents with longer working experience were less likely to sustain those events [OR = 0.47 (0.11); p < 0.001]. Findings from this study suggest that Congolese nurses and laboratory technicians experience a high frequency of injury and BBF events at work, and remain at high risk for occupationally acquired infection. There is a need for periodic capacity-building training for the healthcare workforce to improve infection prevention in health settings, the provision of sufficient and appropriate PPE and SEDs, post-exposure follow-up and keeping records of occupational injuries in hospitals in Congolese healthcare settings. Full article
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15 pages, 1617 KB  
Article
Prevalence and Risk Factors for Congenital Toxoplasmosis in Newborns in the Public Health System in the Eastern Region of the Brazilian Amazon, Northern Tocantins State, Brazil: Retrospective Cohort Study
by Stela B. C. Sousa, Cláudia D. M. Mangueira, Sandro E. Moron, Raphael G. Ferreira, Helierson Gomes, Noé M. E. P. L. Costa, Alex S. R. Cangussu, Bergmann M. Ribeiro, Fabricio S. Campos, Gil R. dos Santos, Raimundo W. S. Aguiar, Kelly M. I. Silva, Alice R. Mazutti, Julliana D. Pinheiro, Frederico Eugênio, Erica E. L. Gontijo, Sara F. de Sousa, Jaqueline C. M. Borges, João B. Neto and Marcos G. da Silva
Trop. Med. Infect. Dis. 2026, 11(1), 13; https://doi.org/10.3390/tropicalmed11010013 - 31 Dec 2025
Viewed by 568
Abstract
Objective: To determine the prevalence of and risk factors for congenital toxoplasmosis in neonates treated in the public health network of the eastern region of the Brazilian Amazon, northern Tocantins state. Methods: A retrospective cohort study was conducted with neonates born to mothers [...] Read more.
Objective: To determine the prevalence of and risk factors for congenital toxoplasmosis in neonates treated in the public health network of the eastern region of the Brazilian Amazon, northern Tocantins state. Methods: A retrospective cohort study was conducted with neonates born to mothers with gestational toxoplasmosis who received care between 2017 and 2024. The outcome under analysis was positivity for immunoglobulin M in the electrochemiluminescence assay (CLIA). We estimated the prevalence of transplacental infection and respective 95% confidence intervals (95% CI) and its association with risk factors using the odds ratio (or) with a p-value < 0.05 in infected neonates before and after 16 gestational weeks at maternal infection diagnosis. Results: A total of 1142 neonates were surveyed, in which 496 were diagnosed with congenital toxoplasmosis (IgM positive), thus obtaining a prevalence of vertical transmission of 45.4%. The main risk factors for vertical transmission were the mother’s education level equal to or less than eight years, (OR = 1.5; 95% CI 1.2; 2.0) and having less than six prenatal consultations (OR = 22.8; 95% CI 3.0; 172.6). Conclusions: A high prevalence of congenital toxoplasmosis was observed, with higher rates of infection in neonates born to mothers with lower levels of education. Full article
(This article belongs to the Special Issue Toxoplasma and Neospora: Public Health Challenges in Tropical Regions)
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16 pages, 322 KB  
Article
Stability and Efficacy of Chlorinated Disinfectants in Beninese Hospitals: Issues for the Prevention and Control of Infections and Antibiotic Resistance
by Sènami Evelyne Soclo Dansi, Comlan Cyriaque Degbey, Alphonse Kpozehouen, Nicolas Gaffan, Affi Diane Agbokou, Ounoussa Tapha, Dona Euloge Saïzonou, Houénoukpo Henri Soclo and Honoré Sourou Bankolé
Trop. Med. Infect. Dis. 2026, 11(1), 12; https://doi.org/10.3390/tropicalmed11010012 - 31 Dec 2025
Viewed by 364
Abstract
In hospitals with limited resources, chlorine solutions are commonly used for biocleaning. The effectiveness of these solutions depends on the concentration of active chlorine and how they are prepared and stored. A study conducted in six University Hospitals in Benin from 10 March [...] Read more.
In hospitals with limited resources, chlorine solutions are commonly used for biocleaning. The effectiveness of these solutions depends on the concentration of active chlorine and how they are prepared and stored. A study conducted in six University Hospitals in Benin from 10 March to 11 July 2025 aimed to evaluate the stability of active chlorine and the bactericidal efficacy of chlorine solutions used for disinfecting hospital environments. A total of 103 samples were analyzed using iodometric titration following the AFNOR (Association Française de Normalisation) standard NF EN ISO 7393-3 (2000) and WHO (World Health Organization) recommendations. Bactericidal activity was tested on multi-resistant hospital strains using the germ carrier method based on the standard NF T72-281. The study revealed that 88.4% of the solutions had inadequate active chlorine concentrations. Overall, the bactericidal activity was low, with only 14.6% effectiveness compared to 85.4% ineffectiveness. Ineffectiveness was particularly pronounced against Gram-negative bacilli, with 79.6% ineffectiveness and 20.4% effectiveness. Similarly, Gram-positive cocci showed a high level of ineffectiveness, reaching 84.5%, corresponding to 15.5% effectiveness. A significant association was observed between compliance with active chlorine concentrations and bactericidal effectiveness, with an OR of 42.5 and a p-value below 0.000001. Factors contributing to inefficiency included storage without light protection, use of transparent containers, storage for more than two days, inadequate active chlorine concentration, and incorrect pH levels. These issues compromise hospital disinfection and contribute to the persistence of multi-resistant bacteria in the hospital environment. Full article
17 pages, 2152 KB  
Article
Dengue Incidence Following Mass Vaccination: An Interrupted Time Series Study in Paraná, Brazil
by Magda Clara Vieira da Costa-Ribeiro, Elias Teixeira Krainski, Angela Maron de Mello, Denise Siqueira de Carvalho, Karin Regina Luhm, Fredi Alexander Diaz-Quijano, Sonia Mara Raboni, Lineu Roberto da Silva, Marilene da Cruz Magalhães Buffon, Eliane Mara Cesário Pereira Maluf, Gabriel Graef, Gustavo Araújo de Almeida, Clara Preto and Silvia Emiko Shimakura
Trop. Med. Infect. Dis. 2026, 11(1), 11; https://doi.org/10.3390/tropicalmed11010011 - 30 Dec 2025
Cited by 1 | Viewed by 786
Abstract
In southern Brazil, dengue transmission in the state of Paraná has shown a significant increase in the number of cases since the first recorded occurrence in 1995, with more frequent outbreaks in the west, northwest, and north of the state. We evaluated the [...] Read more.
In southern Brazil, dengue transmission in the state of Paraná has shown a significant increase in the number of cases since the first recorded occurrence in 1995, with more frequent outbreaks in the west, northwest, and north of the state. We evaluated the impact of a campaign of dengue vaccination administered to a fraction of the population in 30 municipalities in the state by conducting a 15-year interrupted time-series ecological study using data obtained from an official Brazilian data register. We modeled dengue incidence using Poisson regression adjusted by covariates (demographic, climate, and epidemiological factors), allowing for specific temporal variation for each site. A reduction of 18.7% in dengue incidence rate was estimated for a vaccination coverage of 100%. Although there was an increase in the crude dengue incidence rate, considering the three-dose coverage achieved in the municipalities, we estimated an 8.2% relative reduction in the incidence rate. This reduction would increase to 17% with a hypothetical coverage of 90%. The campaign was more effective in small municipalities since they had higher vaccination coverage. These findings underscore the significant impact of the vaccination campaign on reducing dengue incidence trends across the targeted municipalities. Full article
(This article belongs to the Special Issue Beyond Borders—Tackling Neglected Tropical Viral Diseases)
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18 pages, 11537 KB  
Article
Analysis of the Specific Expression Profile of Immune Cells in Infants and Young Children Infected with RSV and Construction of a Disease Prediction Model
by Kai Ren, Honggang Sun, Tian Ren, Kailun Ma and Jizheng Chen
Trop. Med. Infect. Dis. 2026, 11(1), 10; https://doi.org/10.3390/tropicalmed11010010 - 29 Dec 2025
Viewed by 428
Abstract
It has been demonstrated that infants and young children exhibit immune tolerance as a consequence of immature immune systems, which are characterized by a natural Th2 bias. RSV infection has been reported to result in acute lower respiratory infection (ALRI), while formalin-inactivated vaccination [...] Read more.
It has been demonstrated that infants and young children exhibit immune tolerance as a consequence of immature immune systems, which are characterized by a natural Th2 bias. RSV infection has been reported to result in acute lower respiratory infection (ALRI), while formalin-inactivated vaccination has been observed to exacerbate Th2 responses, consequently leading to enhanced respiratory disease (ERD). Transcriptomic data from three independent cohorts of RSV-infected infants were analyzed (GSE246622 served as the discovery and train set; GSE105450 and GSE188427 were used as validation sets). Immune infiltration analysis revealed immunological characteristics, which were then used to perform unsupervised clustering using feature-related genes. WGCNA was used to identify co-expressed gene modules, while Mfuzz and TCseq were employed to analyze temporal expression patterns. Machine learning models were developed using a refined panel of candidate genes. Severe symptoms of RSV infection exhibited a strong correlation with age, with younger infants demonstrating more intense inflammatory responses from neutrophils, macrophages, mast cells and dendritic cells. A predictive model was constructed using ten co-expressed genes: The following genes were identified: MCEMP1, FCGR1B, ANXA3, FAM20A, CYSTM1, GYG1, ARG1, SLPI, BMX and SMPDL3A. It was observed that infants of a younger demographic demonstrated a heightened degree of immunosuppression and pronounced innate immune activation in patients of severe symptoms with RSV infection. However, eosinophils exhibited minimal involvement in these processes. These gene models pertaining to the neutrophil, macrophage or mast cell was found to be a relatively effective predictor in patients of severe symptoms. Full article
(This article belongs to the Special Issue Immune Responses in Respiratory Infections)
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14 pages, 2459 KB  
Article
Finding the Gaps: Integrated Serosurveillance and Spatial Clustering of Vaccine Preventable Diseases in Samoa, 2018–2019
by Selina Ward, Harriet L. S. Lawford, Benn Sartorius, Helen J. Mayfield, Filipina Amosa-Lei Sam, Sarah Louise Sheridan, Robert Thomsen, Satupaitea Viali and Colleen L. Lau
Trop. Med. Infect. Dis. 2026, 11(1), 9; https://doi.org/10.3390/tropicalmed11010009 - 28 Dec 2025
Viewed by 454
Abstract
Introduction: Seroprevalence of antibodies for vaccine-preventable diseases (VPDs), due to vaccination or previous infection, can provide a more accurate estimate of immunity compared to vaccination coverage data alone. This study aimed to examine the seroepidemiology and spatial distribution of VPD seroprevalence in Samoa [...] Read more.
Introduction: Seroprevalence of antibodies for vaccine-preventable diseases (VPDs), due to vaccination or previous infection, can provide a more accurate estimate of immunity compared to vaccination coverage data alone. This study aimed to examine the seroepidemiology and spatial distribution of VPD seroprevalence in Samoa in 2018 and 2019. Methods: Dried blood spot (DBS) samples were collected from two nationally representative community-based surveys of participants aged ≥5 years from the Surveillance and Monitoring to Eliminate Lymphatic Filariasis and Scabies from Samoa (SaMELFS) project. DBSs were tested using multiplex bead assays (MBAs) to detect antibodies against measles, rubella, diphtheria, and tetanus. Seroprevalence was estimated at the national and primary sampling unit (PSU) levels, and cluster analysis was completed using SaTScan. Results: Overall, 8394 valid MBA results were analysed across 35 PSUs. The highest overall seroprevalence was observed for tetanus (91.0%; 95% CI: 90.2–91.7), followed by diphtheria (83.7%; 95% CI: 82.7–84.7), rubella (79.3%; 95% CI: 78.2–80.3), and measles (45.8%; 95% CI: 44.8–46.9) with substantial heterogeneity across PSUs. Clusters of seronegativity to measles (relative risk [RR]: 1.16, p < 0.001) and diphtheria (RR: 1.16, p < 0.001) were also identified. Conclusions: These findings demonstrate significant variation in seroprevalence and pockets of low population immunity to multiple VPDs, highlighting the key advantage of an integrated rather than siloed approach. The relatively high seroprevalence to rubella suggests potential community transmission, emphasising the need to strengthen congenital rubella surveillance and improve vaccination coverage. Identifying low immunity to VPDs can provide an early warning to potential outbreak risk and support the Ministry of Health to target public health interventions in higher-risk areas. Full article
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10 pages, 3332 KB  
Article
Incidence and Spatial Mapping of Tuberculosis and Multidrug-Resistant Tuberculosis in Libreville, Republic of Gabon, in 2022
by Casimir Manzengo, Nlandu Roger Ngatu, Stredice Manguinga-Guitouka, Fleur Lignenguet, Ghislaine Nkone-Asseko, Marie Nsimba-Miezi, Nobuyuki Miyatake, Jose Lami-Nzunzu and Tomohiro Hirao
Trop. Med. Infect. Dis. 2026, 11(1), 8; https://doi.org/10.3390/tropicalmed11010008 - 27 Dec 2025
Viewed by 590
Abstract
Background: Tuberculosis (TB) remains a major global health problem, and the WHO central Africa region continues to bear the heaviest disease burden. Gabon is one of the high-TB-burden countries in the world; however, its national TB program performance remains weak despite financial support [...] Read more.
Background: Tuberculosis (TB) remains a major global health problem, and the WHO central Africa region continues to bear the heaviest disease burden. Gabon is one of the high-TB-burden countries in the world; however, its national TB program performance remains weak despite financial support from international health agencies. Identifying and mapping high-TB- and multi-drug-resistant-TB (MDR-TB)-burden areas for targeted public health interventions was the objective of this study. Methods: A region-wide mixed method study was carried out, comprising ecological design and a desk review, with the use of medical records from TB diagnosis and care units in 12 health facilities located across the capital Libreville, Republic of Gabon, from 1 January through December 2022. Libreville is the region that bears the heaviest TB burden in Gabon. With the collaboration of the Agency for Space Studies and Observations (AGEOS, Gabon), collected data were transferred to and analyzed using QGIS software in order to develop satellite images. Results: In the Libreville health region, there were 4560 cases diagnosed in 2022, representing 77.9% of all cases in the country, with an annual incidence of 509 per 100,000. Spatial mapping of incident cases by county of residence showed that a large majority of the TB cases diagnosed at the CHUL care center in 2022 were from Nzeng-Ayong (range: 36–50 cases) and Owendo (26–35 cases), whereas higher TB incidence at the Nkembo care center was from Nzeng-Ayong (range: 356–455 cases) and Owendo (256–355 cases), followed by Nkembo, Akebe ville, Akebe Baraka, Akebe Plaine/plateau, Angondje, Angondje village, Charbonnages, Bikele, Pk11, Pk12, Pk9, Mindoube I, Mindoube II (66–255 cases), Sotega, and Nkok (46–65 cases). Other counties accounted for less than 45 TB cases. Considering MDR-TB cases, higher incidence was observed in Pk9 county, which accounted for six cases (14.6%), followed by Owendo, accounting for four (9.7%). Discussion: Findings suggest that Nzeng-Ayong and Owendo are high-TB-burden counties in Libreville, whereas Pk9 and Owendo counties are counties categorized as high-MDR-TB-incidence areas. They should be subject to targeted to public health interventions to enhance TB control in Libreville. Full article
(This article belongs to the Special Issue Tuberculosis Control in Africa and Asia)
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22 pages, 2822 KB  
Article
Community Participatory Approach to Design, Test, and Implement Interventions That Reduce Risk of Bat-Borne Disease Spillover: A Case Study from Cambodia
by Dou Sok, Sreytouch Vong, Sophal Lorn, Chanthy Srey, Madeline Kenyon, Bruno M. Ghersi, Tristan L. Burgess, Marcia Griffiths, Disha Ali, Elaine M. Faustman, Elizabeth Gold, Jonathon D. Gass, Felicia B. Nutter, Janetrix Hellen Amuguni and Jennifer Peterson
Trop. Med. Infect. Dis. 2026, 11(1), 7; https://doi.org/10.3390/tropicalmed11010007 - 27 Dec 2025
Viewed by 569
Abstract
Background/Objectives: The USAID STOP Spillover project in Cambodia aimed to reduce the risk of zoonotic virus spillover from bats to humans in bat guano farming communities. Methods: Using participatory tools, such as Outcome Mapping and Trials of Improved Practices, a team [...] Read more.
Background/Objectives: The USAID STOP Spillover project in Cambodia aimed to reduce the risk of zoonotic virus spillover from bats to humans in bat guano farming communities. Methods: Using participatory tools, such as Outcome Mapping and Trials of Improved Practices, a team of local experts and community members collaboratively designed, tested, and refined biosafety and hygiene practices that are acceptable and sustainable to mitigate the risk of bat-borne disease spillover. We tracked progress and rolled out interventions to promote the adoption of safe behaviors that strengthen the understanding of zoonotic disease and reinforce the adoption of safety practices among bat guano producers and their neighbors. The intervention’s effectiveness was evaluated after three-month trials. Results: An improvement in knowledge, attitudes, and risk reduction practices was observed among participants. The primary motivators for adopting these measures were fear of disease, families’ well-being, cost savings, and experience of the COVID-19 pandemic. Conclusions: The community-driven approach fostered a sense of ownership, enabling participants to find the best solutions for their circumstance for long-term sustainability of the intervention. The findings recommended continued community engagement, improved access to biosafety and hygiene resources, and reinforced routine zoonotic disease surveillance. This model can be applied to mitigate emerging infectious disease spillover risks in similar contexts. Full article
(This article belongs to the Section One Health)
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17 pages, 772 KB  
Review
Spatial Risk Factors of Vector-Borne Diseases in Pacific Island Countries and Territories: A Scoping Review
by Tathiana Nuñez Murillo, Angela Cadavid Restrepo, Helen J. Mayfield, Colleen L. Lau, Benn Sartorius and Behzad Kiani
Trop. Med. Infect. Dis. 2026, 11(1), 6; https://doi.org/10.3390/tropicalmed11010006 - 24 Dec 2025
Viewed by 549
Abstract
This scoping review aimed to identify and synthesise spatially relevant environmental, demographic, and socio-economic factors associated with vector-borne diseases (VBDs) in Pacific Island Countries and Territories (PICTs), a region particularly vulnerable due to its ecological and climate diversity. A systematic search of PubMed, [...] Read more.
This scoping review aimed to identify and synthesise spatially relevant environmental, demographic, and socio-economic factors associated with vector-borne diseases (VBDs) in Pacific Island Countries and Territories (PICTs), a region particularly vulnerable due to its ecological and climate diversity. A systematic search of PubMed, Scopus, and Web of Science was conducted in March 2025 with no time restrictions, yielding 3008 records. After applying the inclusion criteria, 21 studies were selected for analysis. Environmental factors such as temperature, precipitation, and land cover were consistently associated with increased burden of malaria, dengue, and lymphatic filariasis, while associations with elevation and flooding were mixed or inconclusive. Demographic factors, including population density and household composition, were found to be associated with disease occurrence, although the direction and the strength of these associations varied. Three studies reported a negative association between population density and disease outcomes, including lymphatic filariasis in American Samoa and dengue in New Caledonia. Spatial socioeconomic factors such as low income, unemployment, and limited education were positively correlated with disease burden, particularly lymphatic filariasis and dengue. These findings underscore the importance of spatial determinants in shaping VBD transmission across PICTs and highlight the utility of spatial risk mapping to inform geographically targeted vector control strategies. Notably, infrastructure, health care access, and intra-island mobility remain underexplored in the literature, representing critical gaps for future research. Strengthening surveillance through spatially informed public health planning is essential to mitigate disease burden in this climate-sensitive and geographically dispersed region. Full article
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18 pages, 812 KB  
Article
Analysis of Adolescent HIV Care Cascade Outcomes in PEPFAR-Supported Programs in Central America, October 2020–September 2024
by Lissette Raquel Chang, Cristine Gutierrez, Jose Rodas, Nancy Aitcheson, Nasim Farach, Carlos Castaneda, Andres Azmitia Rugg and Benjamin Ryan Phelps
Trop. Med. Infect. Dis. 2026, 11(1), 5; https://doi.org/10.3390/tropicalmed11010005 - 24 Dec 2025
Viewed by 387
Abstract
To better understand recent adolescent (10–19 years) HIV trends in Central America, we analyzed routine data from countries supported by the United States President’s Emergency Plan for AIDS Relief (PEPFAR): Guatemala, El Salvador, Honduras, Panama, and Nicaragua, over the period from October 2020 [...] Read more.
To better understand recent adolescent (10–19 years) HIV trends in Central America, we analyzed routine data from countries supported by the United States President’s Emergency Plan for AIDS Relief (PEPFAR): Guatemala, El Salvador, Honduras, Panama, and Nicaragua, over the period from October 2020 to September 2024. Key PEPFAR indicators included HIV testing, HIV positivity rates, new treatment initiations, advanced HIV disease (AHD) at diagnosis, viral load coverage (VLC), viral load suppression (VLS), and multi-month dispensing (MMD) uptake for children and adolescents living with HIV (CALHIV) from 10–19 years of age. Since October 2020, the number of HIV tests conducted among adolescents has increased; however, the positivity rate has remained stable at approximately 2%. The number of adolescents initiating treatment increased by 21%. At the same time, VLS has shown steady regional improvement (from 73% to 90%), though VLC is a persistent challenge (80%). Treatment interruption rates have been relatively stable, fluctuating between 2% and 3%. Advanced HIV is high in adolescents new to treatment (34%), especially among females (40%), though cluster of differentiation 4 (CD4) testing at diagnosis has only been collected recently and coverage is not complete. The high prevalence of AHD among adolescents underscores the need to reinforce earlier and more targeted interventions for adolescents, especially in countries with greater HIV prevalence such as Panama and Guatemala. Full article
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21 pages, 4659 KB  
Article
In Vitro Assessment of the Combined Activity of Amphotericin B and Cu2+-1,10-Phenanthroline-5,6-dione Coordination Compound Against Leishmania amazonensis Promastigotes
by Simone Santiago Carvalho de Oliveira, Débora Duarte Batista, Michael Devereux, Malachy McCann, Christiane Fernandes, André Luis Souza dos Santos and Marta Helena Branquinha
Trop. Med. Infect. Dis. 2026, 11(1), 4; https://doi.org/10.3390/tropicalmed11010004 - 24 Dec 2025
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Abstract
Leishmaniasis is a severe parasitic disease transmitted by sandflies that affects both humans and animals, with clinical manifestations ranging from cutaneous lesions to life-threatening visceral involvement. Current treatments are limited by toxicity, high cost, and the emergence of drug-resistant strains, underscoring the need [...] Read more.
Leishmaniasis is a severe parasitic disease transmitted by sandflies that affects both humans and animals, with clinical manifestations ranging from cutaneous lesions to life-threatening visceral involvement. Current treatments are limited by toxicity, high cost, and the emergence of drug-resistant strains, underscoring the need for safer and more effective therapeutic strategies. In this study, we investigated the antiparasitic potential of combining Amphotericin B, a drug commonly used for leishmaniasis treatment, with 1,10-phenanthroline-5,6-dione (phendione) coordinated to copper (Cu2+-phendione), an experimental coordination compound, against Leishmania amazonensis promastigotes. The combination markedly impaired parasite proliferation, disrupted ultrastructural integrity, and interfered with metabolic activity. Mechanistic analyses revealed the presence of autophagosomes and pronounced mitochondrial alterations in treated parasites, suggesting the induction of cellular stress and the disruption of essential survival pathways. In addition, the treatment reduced the association index with THP-1 cells, indicating a decrease in parasite infectivity. Collectively, these findings demonstrate that the combination of Cu2+-phendione and Amphotericin B exerts potent antiparasitic effects through multiple mechanisms. Our results also showed that Cu2+-phendione combined with AmB displayed an additive effect, although the isobologram suggested that certain ratios approached synergy. The results support the potential of this combination as a novel chemotherapeutic approach against leishmaniasis and provide a basis for future in vivo studies to evaluate safety, efficacy, and optimal dosing strategies. Full article
(This article belongs to the Section Neglected and Emerging Tropical Diseases)
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