PLOS Neglected Tropical Diseases

IntroductionScabies, caused by Sarcoptes scabiei, is a neglected tropical disease that disproportionately affects underserved rural communities, where transmission is commonly sustained through prolonged close contact and sharing of personal items. This study assessed household scabies experience and associated factors during a past outbreak in Nyasa District. MethodsA retrospective community-based cross-sectional study was conducted among 198 households from four villages. Data were collected using an AfyaData-digitized, expert-validated questionnaire aligned with the International Alliance for the Control of Scabies criteria to improve syndromic specificity. Quantitative data were analyzed using univariable and multivariable logistic regression. Open-ended responses (Q24-Q26) were analyzed thematically and triangulated with regression findings. ResultsOverall, 60.6% (120/198) of households reported scabies experience during the outbreak period. In multivariable analysis, higher odds of household scabies experience were associated with sharing personal items (Rarely AOR = 4.059; Frequent AOR = 4.688) and receiving treatment during the outbreak (AOR = 4.705). Non-collaboration with healthcare personnel showed increased odds but was not statistically significant (AOR = 2.035; p = 0.098). Lower odds were observed among households reporting "not sure" responses for prior scabies history (AOR = 0.235) and treatment (AOR = 0.249), suggesting uncertainty-related misclassification. Qualitative themes mapped to these determinants: sharing items aligned with laundry/bedding and clothing hygiene practices ("...kufua... na kuzidisha usafi"); treatment aligned with effectiveness concerns and access/availability barriers ("madawa... hayatibu"; "matibabu mbali"); collaboration aligned with requests for outreach/education and follow-up ("watoa huduma hawakufika..."); and "not sure" responses aligned with misconceptions and uncertainty ("tulifikiri... tumerogwa"). ConclusionThe study demonstrates a substantial household burden of scabies and highlights the need for coordinated outbreak responses that prioritize household-level prevention (reducing sharing of personal items), improved access to effective treatment, and stronger health system-community engagement. Triangulation of regression results with community narratives supports AfyaDatas value for standardized, criteria-informed investigation and targeted public health action in Tanzania. Author SummaryScabies is a contagious skin disease caused by tiny mites that burrow into the skin and cause intense itching and rash. It spreads mainly through prolonged skin-to-skin contact and by sharing personal items such as clothes and bedding. Scabies is common in many low-resource settings, but local evidence is often limited, which makes it difficult to plan effective prevention and outbreak response. We investigated a scabies outbreak that occurred in Nyasa District, southern Tanzania, in September 2022. We interviewed 198 households in four villages using a mobile data collection tool (AfyaData) and a standardized questionnaire informed by international scabies guidance. We found a high household burden of scabies experience. Quantitative analysis showed that households reporting scabies were more likely to report sharing personal items and seeking/receiving treatment during the outbreak, and they also reported weaker collaboration with healthcare personnel. Open-ended responses supported these patterns: participants described the importance of washing clothes and bedding, concerns that medicines were ineffective or difficult to access, and a need for health worker outreach, education, and follow-up. Some responses reflected uncertainty and misconceptions about the cause of illness. Our findings show that scabies outbreak control in rural settings requires household-focused prevention, timely access to effective treatment, and stronger coordination between communities and health services. The study also demonstrates how digital tools can support standardized outbreak investigation and guide targeted public health action aligned to control scabies and other neglected tropical diseases.

BackgroundEchinococcosis is a zoonotic disease caused by cestodes of the genus Echinococcus. Alveolar echinococcosis (AE), caused by E. multilocularis, primarily affects the liver and shows infiltrative, tumor-like growth of the metacestode stage. If untreated, AE is lethal. AE remains a neglected disease with current treatments based on albendazole or mebendazole that are parasitostatic, and not curative, underscoring the need for more effective therapies. Niclosamide is a chlorinated salicylanilide derivative with proven activities against intestinal helminths but is inactive against tissue-dwelling helminths due to poor absorption and limited bioavailability. In this study, we repurposed niclosamide ethanolamine (NEN), a formulation with improved systemic exposure, for the treatment of E. multilocularis infection in vitro and in vivo. Methodology/Principal FindingsWe assessed the in vitro efficacy of niclosamide and NEN against E. multilocularis metacestode vesicles (IC50<0.2 {micro}M) and primary parasite cells (IC50<0.3 {micro}M), with active concentrations largely corresponding to NEN levels reachable in the liver. Metabolic analysis suggested that NEN acts as a mitochondrial uncoupler. Electron microscopy showed that NEN-treatments induced profound structural damage in the metacestode vesicle tissue, but mitochondrial ultrastructure was not notably affected. In mice intraperitoneally infected with E. multilocularis, NEN was orally administered during 9 weeks either alone, or in combination with albendazole. Pharmacokinetic analyses showed that NEN reached blood level concentrations above 1 {micro}M. However, the parasite burden in NEN-treated mice was not significantly reduced. Conclusions/SignificanceAlthough niclosamide and NEN demonstrated potent activity against E. multilocularis in vitro, this efficacy did not translate in the mouse model. The lack of in vivo activity could be attributed to several factors such as infection model, limited drug uptake by the parasite in the animal, or the rapid metabolization of the compound. Future studies should explore novel niclosamide derivatives and formulations to enhance efficacy against AE in vivo. Author SummaryAlveolar echinococcosis (AE) is a severe disease caused by the larval stage of the fox tapeworm Echinococcus multilocularis. The parasite forms tumor-like lesions in the liver and can spread to other organs. The currently licensed drugs for the treatment of AE are not always effective, require long-term use, and can cause side effects that frequently require treatment interruption. Therefore, safer and more efficacious treatment options are urgently needed. Niclosamide is frequently applied for the treatment of adult tapeworm infections in the intestine, but its limited uptake and low biodistribution renders the compound unsuitable for systemic treatment. In this study, we tested a non-toxic salt formulation, niclosamide ethanolamine (NEN), exhibiting improved absorption. In vitro, NEN was highly effective against E. multilocularis metacestode vesicles. It induced profound structural alterations in metacestode vesicles and impaired the mitochondrial membrane potential, and thus interfering in energy production. However, NEN was not effective against AE in experimentally infected mice. Our results suggest that NEN treatment appears promising in vitro, but to translate to the in vivo situation, new formulations and delivery strategies should be developed to increase absorption, bioavailability and metabolic stability of the compound for an effective treatment for AE.

BackgroundSchistosomiasis is one of the most prevalent neglected tropical diseases in Sub-Saharan Africa, causing substantial morbidity and millions of disability-adjusted life years (DALYs). Although the WHO aims to eliminate schistosomiasis as a public health problem in several countries by 2030, limited data on infection prevalence in Zambia has hindered effective Mass Drug Administration (MDA) coverage, contributing to the persistence and resurgence of the disease. MethodsWe assessed the prevalence of urogenital schistosomiasis in two peri-urban districts of Lusaka (Chongwe and Kafue). A total of 208 participants were enrolled, and infection status was determined using microscopy, serological assays, and molecular diagnostics. ResultsPrevalence was significantly higher in Chongwe than in Kafue, as detected by both microscopy and qPCR, demonstrating a strong association between infection and district location. No association was found between sex and infection in either district. However, a significant association between age and Schistosoma haematobium infection was observed across both sites. Molecular characterization of individual eggs revealed that S. haematobium x S. curassoni hybrids were the most prevalent species circulating in the study population. ConclusionsOur findings reveal a high prevalence of urogenital schistosomiasis in at least two peri-urban areas of Lusaka, Zambia, indicating that transmission remains highly active and may be underestimated in national surveillance. Furthermore, the presence of hybrid species infecting humans highlights the need to consider livestock reservoirs when designing elimination strategies. These results provide updated information on the epidemiological situation of urogenital schistosomiasis in Zambia and will support planning and implementation within the WHO NTD agenda. AUTHOR SUMMARYUrogenital schistosomiasis remains a major public health concern in many parts of Sub-Saharan Africa, yet recent data from Zambia are limited, particularly in communities surrounding Lusaka. In this study, we assessed infection levels in two peri-urban districts, Chongwe and Kafue, using a combination of microscopy, serology, and molecular techniques to ensure accurate detection. We found substantial differences in prevalence between the two locations, with significantly higher infection rates in Chongwe, as well as a clear association between age and risk of infection. Molecular characterisation of parasite eggs revealed that hybrid Schistosoma haematobium x S. curassoni forms were the dominant circulating genotypes, indicating potential involvement of animal reservoirs in transmission. These findings demonstrate that transmission remains active and likely underestimated, and they highlight the importance of incorporating updated epidemiological data and potential zoonotic sources into future control and elimination strategies in Zambia.

BackgroundLymphatic filariasis remains a public health concern in many endemic regions, where chronic disease persists despite substantial reductions in transmission. In Ghana, more than two decades of mass drug administration have significantly reduced disease prevalence and transmission; however, chronic manifestations and gaps in community understanding continue to be reported in parts of the north. This study assessed infection status, chronic morbidity burden, and community knowledge in a rural setting in northern Ghana approaching elimination. Methodology/Principal FindingsA community-based cross-sectional study was conducted in Birifor, northern Ghana, from October 2024 to January 2025. A total of 261 residents aged ten years and above were selected using random sampling. Data collection included structured questionnaires, clinical examination for chronic disease, and night blood microscopy for the detection of infection. No microfilariae were detected (0/261; 0%). However, chronic lymphoedema was identified in five individuals (1.9%), all aged over 40 years. Awareness of the disease was high (95.8%), yet only 39.5% of participants demonstrated good community knowledge and perceptions and self-reported preventive practices. Misconceptions regarding transmission, particularly beliefs that the disease is hereditary or caused by spiritual factors, were common. Participation in mass drug administration was high (93.1%). Despite this, chronic disease imposed a notable socioeconomic burden: all affected individuals reported loss of income, and 60% reported additional household income loss due to caregiving. Conclusions/SignificanceThese findings suggest that transmission in the study area is likely very low, although residual infection cannot be excluded; however, chronic disease and gaps in community knowledge persist. Strengthening morbidity management, improving community education, and providing support for affected households are essential. Sustained surveillance and integrated approaches will be critical to prevent resurgence and support long-term elimination efforts. Author SummaryLymphatic filariasis, also known as elephantiasis, is a mosquito-borne disease that can cause long-term swelling of the legs, arms, or genitals. Global efforts have greatly reduced its occurrence, especially through repeated mass drug administration to afflicted communities. However, many people continue to live with chronic swelling caused by past infections, which can affect their ability to work and participate fully in daily life. In this study, we examined the current situation of lymphatic filariasis in a rural community in northern Ghana that has received many years of treatment. We tested people for active infection, assessed signs of chronic disease, and explored what community members know and believe about the disease. We found no evidence of active infection, suggesting that transmission is now very low. However, some individuals were still living with chronic swelling and reported loss of income, while households also experienced financial strain due to caregiving. Although most people had heard of the disease, many did not fully understand how it is transmitted. Our findings show that reducing transmission alone is not enough. Continued education, community support, and access to care are needed to address the long-term impact of the disease and support ongoing elimination efforts.

Background Nepal has set a goal to eliminate lymphatic filariasis (LF) by 2030. As of 2024, Nepal has stopped the mass drug administration (MDA) in 56 of the 64 endemic districts and completed two rounds of MDA in six districts with persistent LF ([&ge;]2% antigen prevalence) using the three-drug regimen of Ivermectin, Diethylcarbamazine, and Albendazole (IDA), exceeding 65% coverage. We subsequently conducted an Epidemiological Monitoring Survey (EMS) to assess the impact of the MDA in reduction of LF infection prevalence below the transmission threshold and examine the factors associated with it. Methods We conducted a cross-sectional EMS nine months after MDA in 12 evaluation units (EUs) across six districts, with two sites per EU. We recruited a total of 7,343 individuals aged [&ge;]20 years, sampled using multi-stage sampling, ensuring at least 300 blood samples collected per site. We collected data on demographics and MDA participation. We performed the LF antigen testing for all participants, followed by night blood microfilariae testing in antigen-positive individuals. Statistical analyses included non-parametric tests, Chi-square and Fishers Exact tests, and multivariable logistic regression to assess outcomes after adjusting for potential confounders. Results Nine of 12 evaluation units (EUs) recorded <1% microfilaremia, meeting the WHO threshold for passing EMS, while three EUs failed with [&ge;]1% prevalence in at least one site. Antigen and MF prevalence were 4.47% and 0.34%, respectively (ratio 13:1). Both Antigen and MF prevalences were significantly associated with female sex (AOR= 0.564, 95% CI: 0.441-0.721 and AOR = 0.326, 95% CI: 0.129-0.826 respectively) and participation in the most recent MDA round (AOR = 0.477; 95% CI: 0.385-0.591 and AOR = 0.089; 95% CI: 0.017-0.464 respectively). MDA uptake was influenced by age (<40 years, AOR = 0.72; 95% CI: 0.653-0.793), sex (female, AOR = 1.438; 95% CI: 1.29-1.603), cross-border residence (AOR = 0.616; 95% CI: 0.558-0.681), and occupation (agriculture and housewife, AOR = 1.144; 95% CI: 1.008-1.298). MF prevalence was also associated with younger age (<40 years, AOR = 0.211; 95% CI: 0.071-0.626). Conclusion The survey indicates progress toward LF elimination, with nine of twelve EUs achieving WHOs <1% microfilaremia threshold after two rounds of IDA-MDA. However, transmission persists in three sites, likely linked to poor MDA participation among specific subgroups--particularly males, younger adults, and cross-border populations. Strengthening MDA coverage and compliance across all demographic and occupational groups, with special focus on border areas, is essential to achieve LF elimination in Nepal.

Combining novel methodologies with ovarian dissection, we estimated life histories for ca. 90,000 individual female Glossina pallidipes and G. m. morsitans sampled from 1988-1999 in Zimbabwes Zambezi Valley. Using temperature-dependent development rates we stepped back through each flys life, fixing dates of successive pregnancies, adult emergence, pupal period, pregnancy and oogenesis. This enabled modelling of relationships between wing and egg lengths, and conditions prevailing when these lengths were being determined. Egg lengths increased with maternal wing length, were shorter in primiparous flies but changed little with age thereafter. G. pallidipes egg lengths were positively related to NDVI and negatively to temperature (R2 = 0.68), for variables averaged over the period of oogenesis for each fly, and then averaged again across weekly cohorts of flies. G. m. morsitans mean egg lengths, pooled by month, showed the same pattern (R2 = 0.53). Pooled mean wing lengths increased with NDVI and decreased with temperature prevailing while flies were developing in the ovaries and uterus; R2= 0.66 (G. pallidipes) and R2= 0.56 (G. m. morsitans). The models - fitted using flies captured after November 1991 - gave good predictions, with no further modeling, for egg and wing lengths of flies captured between September 1988 and November 1991. The models facilitate true predictions of future changes in fly size based on readily available meteorological data, benefiting vector and disease control efforts in predicting likely changes in tsetse population densities and distribution. Selection against small individuals in the hot-dry season is not restricted to teneral mortality continuing for some weeks after emergence. NDVI, measures of wetness and temperature can indirectly impact tsetse size, mortality and population density by affecting vertebrate host density and, thereby, the probability of tsetse locating and feeding on a host. Our methodology impacts numerous areas of vector biology and control.

BackgroundDengue fever is an emerging public health concern in Burkina Faso, with increasing outbreaks and data gaps in population awareness. This study assessed knowledge, attitudes, and practices (KAP) related to dengue fever in all health regions of the country. Methodology/Principal FindingsA nationwide cross-sectional household survey was conducted in May 2022 using a stratified two-stage cluster sampling design. One rural and one urban area were selected per region. Heads of households or their representatives were interviewed using a structured questionnaire. Data were collected electronically and analyzed using Stata. A total of 1,568 participants were enrolled (52.0% male; 48.0% female). Overall, 66.3% had heard of dengue, with higher awareness in urban than rural areas. Only 49.0% correctly identified mosquito bites as the mode of transmission, and 29.9% did not know what dengue is. Most respondents (88.3%) stated that dengue can affect everyone. Regarding prevention, 80.2% reported sleeping under a mosquito net, 49.0% eliminated stagnant water, and 45.4% used mosquito repellents. In practice, 67.6% consistently slept under mosquito nets and 82.6% used repellents. Almost all respondents (98.6%) reported that they would consult a health professional if they had symptoms of dengue. However, knowledge about treatment and vaccination was limited, with 46.5% and 56.6% respectively reporting not knowing whether drugs or vaccines exist. Conclusions/SignificanceThis study highlights moderate awareness but substantial knowledge gaps and urban-rural disparities in dengue-related KAP in Burkina Faso. Strengthening community-based education and integrated vector control strategies is essential to improve prevention and reduce dengue transmission. Author SummaryDengue fever is a mosquito-borne disease that is spreading in many parts of the world, including West Africa. In Burkina Faso, outbreaks have been reported in recent years, but little is known about what communities understand about the disease or how they protect themselves. In this study, we conducted a nationwide household survey covering all health regions of the country to explore peoples knowledge, perceptions, and prevention practices related to dengue. We found that while many people had heard about dengue, important gaps remain. A significant proportion did not know how the disease is transmitted or whether treatments or vaccines exist. Preventive actions such as sleeping under mosquito nets and removing standing water were reported, but these practices were not consistent everywhere, especially between urban and rural areas. Encouragingly, almost all respondents said they would seek care from a health professional if they developed symptoms. Our work provides the first national picture of community awareness and behaviors related to dengue in Burkina Faso. These findings highlight the need for strengthened health education and community engagement to improve prevention and support ongoing efforts to control mosquito-borne diseases.

BackgroundSchistosomiasis causes substantial chronic morbidity in sub-Saharan Africa, yet case definitions, clinical management guidance, and health worker training for schistosomiasis-related morbidity remain limited. MethodologyWe conducted a qualitative needs assessment for schistosomiasis morbidity management. Workshops were held over one day in each of Pakwach, Buliisa, and Mayuge Districts in Uganda in October 2024. 105 government health workers participated including clinicians, nurses, laboratory technicians, sonographers, and district health managers from health facilities at different levels of care. The workshops comprised six structured sessions: presentations on schistosomiasis burden in Uganda and the SchistoTrack cohort, a clinical case report by an expert clinician, an interactive session on patient case studies from the SchistoTrack cohort, mapping of patient pathways, anonymous participation and feedback, and demonstrations of schistosomiasis diagnosis. Workshop discussions were documented through notes taken in English and analysed using qualitative thematic analysis as per Braun and Clarke. FindingsHealth workers demonstrated substantial gaps in understanding schistosomiasis case definitions, particularly in distinguishing current infection from chronic morbidity and in grading disease severity. Patient pathways for schistosomiasis morbidity management were fragmented and inconsistent, with weak triage, unclear referral and feedback mechanisms, and limited follow-up across facility levels. Health facilities lacked essential capacity and resources, including routine access to praziquantel outside mass drug administration, diagnostic reagents, functional ultrasound equipment, trained sonographers, and standardized training and reference tools. Collectively, these gaps contributed to inconsistent clinical decision-making and under-recognition of severe schistosomiasis-related morbidity. ConclusionsIntegrating case management into routine health services through standardized case definitions, clearer patient pathways, and targeted practical training for health workers is essential to complement preventive chemotherapy and reduce preventable morbidity. The engagement framework and patient case studies used here can support needs-based assessments in other endemic settings to inform the development of context-appropriate clinical guidance and training programmes. Author summarySchistosomiasis is a disease common in sub-Saharan Africa that can cause serious, lifelong health problems, even after the infection itself has been treated. While mass drug administration programmes have reduced infections, we found that health facilities are often not equipped to recognize or manage the chronic illness that remains after mass drug administration. In this study, we worked with government health workers in three rural districts of Uganda to understand their experiences, challenges, and training needs related to schistosomiasis morbidity. Through interactive workshops, we learned that many health workers struggle to distinguish between current infection and long-term organ damage, especially liver disease. Patient care pathways were often unclear, referrals were poorly coordinated, and essential tools, such as diagnostic supplies, ultrasound access, and routine availability of treatment, were frequently missing. These gaps make it difficult to identify severe cases early and provide consistent care. We show that strengthening routine health services through clearer case definitions, better training, and more coordinated patient pathways is essential to reduce preventable suffering from schistosomiasis. Our approach offers a practical way to support health systems in other endemic settings facing similar challenges.

BackgroundScrub typhus is a major yet neglected vector-borne disease in Thailand, where it has been nationally notifiable for over two decades. However, long-term changes in its epidemiology, including reporting rates, transmission intensity, disease severity, and seasonal patterns, have not been comprehensively characterised at the national level. MethodologyWe analysed 22 years of national surveillance data for scrub typhus in Thailand (2003-2024) using a latent process model that jointly fits reported cases with published nationwide seroprevalence data and antibody kinetics to estimate reporting rates and underlying transmission dynamics across all 77 provinces of Thailand. FindingsOver the 22-year study period, 143096 cases and 119 deaths were reported nationally. Estimated reporting proportion broadly mirrored transmission intensity, being higher in high-burden regions and lower elsewhere. A synchronous decline in detection was observed across all regions during the COVID-19 pandemic, followed by rapid rebound by 2024. After accounting for these reporting dynamics, the force of infection was highest in the northern provinces but also substantial in the northeast and south, with upward trends in some provinces. Susceptibility among older adults aged 65 and above increased progressively over the study period, reversing the pattern observed two decades earlier. Case-fatality in the 25-35-year reference group was low and declined from 0.14% (95% Credible Interval [CrI]: 0.06-0.29%) to 0.06% (95% CrI: 0.02-0.12%), but relative case-fatality remained consistently highest among adults above 65 across all periods. Three geographically distinct seasonal patterns were identified, all stable over time. ConclusionOver two decades, scrub typhus transmission in Thailand has been shown to extend well beyond its traditionally recognised northern focus, with substantial burden in previously underappreciated regions, while the demographic profile of those most affected has shifted progressively toward older adults. These findings support the need for regionally tailored surveillance, age-targeted clinical preparedness, and sustained investment in understanding the ecological drivers of transmission. Key messagesScrub typhus is a common but neglected cause of fever in Thailand, where it has been reported through the national surveillance system for over two decades. However, trends in reported cases can be misleading because they reflect not only true changes in transmission but also variation in diagnosis and reporting over time and across regions. We developed a model that combines surveillance data with seroprevalence surveys and antibody kinetics to separate true changes in transmission from variation in reporting, allowing us to estimate how transmission intensity, disease severity, and seasonal patterns have evolved from 2003 to 2024 across all 77 provinces. We found that substantial transmission occurs not only in the well-studied northern provinces but also in the northeast and south, where the disease has received less attention. Susceptibility has progressively shifted toward older adults, who also face the highest case-fatality, while three distinct seasonal patterns vary by region but have remained stable over time. These findings suggest that scrub typhus control in Thailand requires a shift from a predominantly northern focus toward regionally tailored strategies that account for local transmission timing, an ageing at-risk population, and the ecological drivers that sustain transmission in each setting.

BackgroundLeishmaniasis is endemic in southern Europe with high risks of outbreaks and geographical spread. However, the risk factors for human leishmaniasis are understudied in this region. MethodologyTo evaluate these risk factors, we tested associations between leishmaniasis incidence and an array of variables related to socioeconomics, immunocompetence, climate, land use, biodiversity, and ecology (i.e., the pathogen and its vectors and reservoirs). FindingsSocioeconomic factors, such as demography, occupation, and housing conditions, were strongly associated with leishmaniasis incidence in endemic regions. The specific factors and the magnitude of their impacts varied among the five countries studied. Human immunosuppressive condition was highly correlated with leishmaniasis risk in Spain and Italy. Climate likely delineated leishmaniasis-free regions from endemic regions in France. Our results suggest that climate change alone may not drive the spread of leishmaniasis within this century. Pathogen hazard and reservoir abundance affected leishmaniasis risk more than vector hazard in countries where data were available. Biodiversity was weakly, negatively related to leishmaniasis. SignificanceOur results highlight the importance of socioeconomic risk factors and immunosuppression for human leishmaniasis, suggesting potential implications for disease control and prevention policies. Surveillance of Leishmania spp. in humans, vectors, and reservoirs; assessment of reservoir abundance; and data accessibility are crucial for disease prevention and preparedness. Because of possible biodiversity regulation, efforts to understand and control leishmaniasis could benefit from a One Health approach that involves epidemiologists, social scientists, and ecologists, among others. Author summaryLeishmaniasis is a common disease in tropical and subtropical regions, but it also occurs in southern Europe. While some infectious disease experts are concerned that climate change might lead to the emergence of new diseases in new areas, the main factors shaping leishmaniasis in Europe are not well understood. This study considered a wide array of potential risk factors in a variety of categories, ranging from climate and nature to how people live and work. We found that the risk for leishmaniasis is mostly related to occupation, housing type, age, and sex, though the exact risk factors change from country to country. People with weakened immune systems face high risk, and infected animals pose a major threats, but climate change alone may not drive the spread of leishmaniasis as much as once feared. Interestingly, a healthy variety of wildlife may help keeping the disease in check. To limit the impacts of leishmaniasis, we need to protect the most vulnerable populations, such as people living with weakened immune systems, working in high-risk sectors, residing in single-dwelling buildings, or experiencing or facing homelessness. We need to monitor the parasite in people and animals and share those surveillance data openly. Ultimately, we need a "One Health" approach where doctors, social workers, and scientists work together to keep our ecosystems healthy and our communities safe.

BackgroundSnakebite envenoming (SBE) remains a major neglected tropical disease in Sudan. Venom-induced consumption coagulopathy (VICC) is the most frequent and fatal systemic complication, particularly following envenoming by hemotoxic Echis species. Robust clinical data on VICC in Sudan are limited. MethodsWe conducted a prospective hospital-based cohort study at Sinja Teaching Hospital, Sennar state, Sudan, from March to September 2022. All patients admitted with SBE were enrolled. VICC was diagnosed using the 20-minute whole blood clotting test (WBCT20) and laboratory coagulation assays. Clinical features, laboratory abnormalities, management, and outcomes were recorded until discharge or death. ResultsAmong 119 patients with SBE (mean age 34.5 {+/-} 9 years; 79.8% male), VICC developed in 96 (80.7%). Echis spp. were implicated in 86.6% of cases based on patient recognition. Spontaneous systemic bleeding occurred in 88.5% of VICC patients, and life-threatening hemorrhage in 30.2%, most commonly intracerebral hemorrhage. Acute kidney injury occurred in 36.5% of VICC cases. WBCT20 was positive in all VICC patients and showed high diagnostic sensitivity. Despite administration of fresh frozen plasma, mortality among VICC patients was 30.2%. All paediatric patients died. ConclusionsVICC was highly prevalent and associated with severe hemorrhage, acute kidney injury, and high mortality in this snakebite-endemic region of Sudan. Supportive therapy alone was insufficient to prevent fatal outcomes, reflecting delayed presentation and the absence of effective Echis-specific antivenom. Improved access to species-appropriate antivenom, early referral, and adherence to evidence-based management are critical to reducing snakebite-related mortality in Sudan. Author SummarySnakebite envenoming is a neglected tropical disease that disproportionately affects rural and agricultural communities in low-resource settings. In Sudan, snakebite remains a major but underreported cause of illness and death. One of its most serious complications is venom-induced consumption coagulopathy (VICC), a disturbance of blood clotting that can lead to severe bleeding and organ failure. We studied all patients admitted with snakebite envenoming to a teaching hospital in southeastern Sudan over six months. More than 80% of patients developed VICC, most often following bites attributed to Echis species, which are common in this region. Many patients experienced spontaneous bleeding, and nearly one-third developed life-threatening hemorrhage, most frequently bleeding in the brain. Acute kidney injury was common. Despite supportive treatment, almost one-third of patients with VICC died, and all children in the study died. Our findings highlight the severe and largely preventable burden of snakebite envenoming in this setting. Delayed presentation to hospital, reliance on traditional healers, and the lack of effective antivenom against locally prevalent snake species contributed to poor outcomes. This study highlights the urgent need to improve access to appropriate antivenom, strengthen health-care systems, and implement evidence-based management of snakebite envenoming to reduce avoidable deaths and disability in Sudan.

India carries a high burden of neglected tropical diseases (NTDs), yet the extent to which essential diagnostic services align with local disease burden across public health facilities remains unclear. We conducted a cross-sectional assessment of diagnostic availability for major NTDs in 332 public health facilities across seven states and one union territory, including sub-centers, primary health centers, community health centers, and district hospitals. Diagnostic availability for malaria, dengue, Japanese encephalitis, chikungunya, lymphatic Filariasis, Leishmaniasis, helminthic infections, and HIV was evaluated using the ICMR National Essential Diagnostics List (2019), and a Diagnostic Readiness Index (DRI) was calculated at the facility, district, and state levels. Big three diseases like tuberculosis, malaria, and HIV are not neglected anymore in terms of funding and research, but their interaction with classic NTDs highlights how these diseases, though different in classification, create a dual burden in vulnerable populations, like in India. Diagnostic readiness increased with higher levels of care but showed limited concordance with disease burden. Malaria diagnostics were widely available across all tiers (mean district DRI: 84.34%), reflecting sustained programmatic prioritization. In contrast, diagnostic availability for dengue (40.36%), lymphatic Filariasis (29.22%), helminthic infections (25.30%), Japanese encephalitis (8.13%), and Leishmaniasis (5.72%) remained low, including in districts reporting substantial disease burden. The greatest mismatch between burden and diagnostic availability was observed at sub-centers and primary health centers, whereas district hospitals showed a more favorable alignment. These findings indicate that essential diagnostic deployment for NTDs in India remains uneven and weakly responsive to epidemiological need. Strengthening burden-informed, decentralized access to point-of-care diagnostics--particularly at peripheral and primary care levels--is critical to improve early case detection, surveillance accuracy, and progress toward national NTD control and elimination targets. Author SummaryNeglected tropical diseases (NTDs) continue to affect millions of people in India, particularly those living in underserved and resource-limited settings. Early and accurate diagnosis is essential for timely treatment, surveillance, and control; however, the availability of essential diagnostic services across different levels of the public health system remains poorly understood. In this study, we assessed the availability of diagnostics for major NTDs across 332 public health facilities, including sub-centers, primary health centers, community health centers, and district hospitals in seven states and one union territory, using the ICMR National Essential Diagnostics List (2019) and a Diagnostic Readiness Index. We found that diagnostic readiness generally increased with higher levels of care but showed limited alignment with local disease burden. Malaria diagnostics were widely available, reflecting sustained programmatic prioritization, whereas diagnostics for dengue, lymphatic filariasis, helminthic infections, Japanese encephalitis, and leishmaniasis were markedly limited, even in areas with substantial reported burden. The largest gaps were observed at peripheral and primary care facilities, which are often the first point of contact for vulnerable populations. Our findings highlight a critical mismatch between disease burden and diagnostic deployment for NTDs in India. Strengthening decentralized, burden-informed access to point-of-care diagnostics--especially at sub-centers and primary health centers--could improve early case detection, enhance surveillance accuracy, and support more effective control and elimination efforts. This study provides policy-relevant evidence to guide health system strengthening and equitable diagnostic access for NTD-endemic regions.

BackgroundTemperature choice is a vector trait that influences microhabitat selection and can have important implications for vector species, as it may affect how often vectors encounter hosts. Aedes aegypti and Ae. albopictus are disease vectors whose geographic ranges continue to expand each year. One aspect that remains largely understudied is the altitudinal range of these species and the extent of differences in thermal behavior between lowland and highland populations. MethodsI collected Ae. aegypti and Ae. albopictus on the islands of Bioko and Sao Tome. I compared the distribution of the two species along an altitudinal cline spanning 2,000 m of elevation. I then used live specimens to test temperature preference for both species in a laboratory thermocline. ResultsI report the distribution of these two species on the island of Bioko and show that the abundance of immature stages of both species follows a negative exponential decay with altitude. I compare this distribution with that observed on the neighboring island of Sao Tome, also in the Gulf of Guinea. Overall, the distribution patterns of the two species are similar, but models indicate a higher abundance at sea level in Sao Tome than in Bioko. I used specimens from this survey to study temperature preference under controlled conditions. I found no significant differences between species or between sexes; however, I detected an altitudinal cline in temperature preference, with high-elevation populations preferring cooler temperatures on both islands. ConclusionsThese results indicate the presence of phenotypic variation in a key trait--temperature choice--that may alter the likelihood of contact between these vectors and humans.

Leishmaniases remain a significant global public health threat, with Leishmania amazonensis and Leishmania infantum representing the etiological agents of the cutaneous and visceral forms in the Americas, respectively. Building on our previous identification of Phospholipase A1 (PLA1) in Leishmania braziliensis, this study provides a comprehensive molecular, immunological, and biochemical characterization of PLA1 in L. amazonensis and L. infantum promastigotes. We analyzed PLA1 activity and expression, purified the recombinant enzyme from L. amazonensis, and validated protein expression using a specific anti-PLA1 serum. The major contribution of this research is the first description of the subcellular localization of a PLA1 within the Leishmania genus. Moreover, our results reveal an unprecedented association between PLA1 and lipid droplets within the parasites. This discovery is of particular interest as it provides the first evidence linking this enzyme to lipid storage organelles in Leishmania. Given that PLA1 is an established virulence factor in other trypanosomatids, these findings suggest a specialized role for the enzyme in parasite lipid metabolism and potentially in its pathogenic mechanisms, opening new perspectives for understanding Leishmania biology.

BackgroundLoiasis is a chronic filarial infection endemic to Central and West Africa. Although long considered benign, increasing evidence links loiasis to substantial morbidity and mortality. The infection is associated with immune modulation, including Th2-skewed responses and elevated regulatory cytokines. Clinically, loiasis is classified as microfilaremic (presence of circulating microfilariae) or amicrofilaremic ("occult") disease, the latter defined by a history of eyeworm migration without detectable microfilaremia. This study investigated how chronic L. loa infection influences antibody and T cell responses to SARS-CoV-2 following natural infection. MethodsBetween 2022 and 2024 this cross-sectional study was done in Lambarene and surrounding rural areas of Gabon. Study procedures included diagnostics for loiasis and immunological assays. Microfilaremia was confirmed by stained blood smear microscopy, and occult disease was identified using the Rapid Assessment Procedure for Loiasis. SARS-CoV-2-specific IgG responses to spike and nucleocapsid proteins were measured by ELISA, and IFN-{gamma} responses to spike antigen were assessed using an interferon-gamma release assay. ResultsOverall, 192 participants were categorized as microfilaremic (n=43), occult loiasis (n=59), or without evidence of active loiasis (n=90). IFN-{gamma} responses were reduced in microfilaremic individuals compared with other participants (p= 0.031), whereas IgG responses did not differ. Subsequent analysis across the three groups confirmed that IFN-{gamma} responses were lower in microfilaremic compared with occult participants (p= 0.012). ConclusionThese findings suggest that microfilaremic loiasis may impair proinflammatory T cell responses to viral antigens, highlighting the need for further research into the broader immunological effects of Loa loa infection in endemic populations. Authors summaryLoiasis is a parasitic infection caused by the worm Loa loa and is common in parts of Central and West Africa. Although long considered relatively benign, growing evidence indicates that loiasis is associated with substantial morbidity. The immunological consequences of chronic Loa loa infection remain poorly understood. A small number of studies suggest that Loa loa may influence immune regulation, but its broader impact on antiviral immunity is largely unknown. The COVID-19 pandemic provided a unique opportunity to examine immune responses to a newly emerging virus in a population where loiasis is endemic. We therefore investigated how different forms of Loa loa infection influence immune responses after natural SARS-CoV-2 infection. We compared individuals with circulating microfilariae in their blood (microfilaremic), individuals with occult loiasis (history of eye worm), and individuals without signs of active infection. We found that microfilaremic individuals had weaker virus-specific IFN-{gamma} T cell responses, while antibody levels were similar across groups. These findings suggest that active loiasis may dampen certain antiviral immune functions. Understanding the underlying mechanisms is important, as such immune modulation could affect responses to vaccines and other infectious diseases in endemic regions.

BackgroundIn 2018, Samoa was the first country to distribute nationwide triple-drug mass drug administration (MDA) for lymphatic filariasis (LF) elimination. Prevalence of filarial antigen (Ag) is the main programmatic indicator used to define elimination target thresholds; however, anti-filarial antibodies (Ab) may provide more sensitive measures of transmission compared Ag. We aimed to investigate the utility of Ag and Ab to measure the impact of one round of triple-drug MDA on LF transmission in Samoa after 7-9 months. MethodsTwo community-based cross-sectional serosurveys of [&ge;]5-year-olds were conducted in 2018 (1-3 months post-MDA) and 2019 (7-9 months post-MDA) in 35 primary sampling units. Ag was detected by Alere Filariasis Test Strips (FTS). Multiplex bead assays (MBA) were used to detect Ab-seropositivity (Bm14 Ab, Wb123 Ab) using Ab-specific mean fluorescence intensity minus background (MFI-bg). Thresholds of seropositivity were determined using finite mixture models (FMM) for log-transformed MFI-bg, defined as the mean of the presumed seronegative class plus three standard deviations. Seroprevalence was adjusted for study design, age, and gender. FindingsA total of 3795 participants (mean age: 20.7; 49% male) were surveyed in 2018 and 4052 (mean age: 20.4; 48% male) in 2019. Between surveys, adjusted Bm14 Ab prevalence decreased (31.2% [95% CI=27.0-35.8] vs 26.3% [95% CI=22.5-30.4]; p=0.02). In 2019 vs 2018, lower odds of Bm14 Ab-positivity (aOR=0.76 [0.64-0.90]), Wb123 Ab-positivity (aOR=0.70 [0.55-0.89]), and dual positivity (aOR=0.68 [0.54-0.87]) were seen. Ag-positive, microfilariae (Mf)-positive participants had significantly higher mean MFI-bg for Wb123 Ab and Bm14 Ab compared to Ag-positive, Mf-negative participants. ConclusionSignificant reductions in Bm14 Ab seroprevalence suggest reduced LF transmission following one round of triple-drug MDA. Thus Abs may provide a more sensitive indicator of change compared to Ag. High MFI values could help identify persistent transmission in the absence of Ag testing. Author summaryLymphatic filariasis is a mosquito-borne disease that can cause lifelong disability and stigma. The main global strategy to eliminate this disease is to treat entire at-risk communities with preventive medicines, aiming to stop transmission altogether. Progress is usually measured using rapid tests that detect parasite antigens in blood. However, as infection becomes rarer, these tests may miss remaining cases, raising concerns that ongoing transmission could go undetected. In this study, we examined whether measuring antibodies in blood could provide earlier or more sensitive signals of infection following treatment. We analysed blood samples collected from communities in Samoa at two time points after a nationwide treatment campaign using a three-drug combination. We found clear reductions in some antibodies over time, even though antigen levels remained largely unchanged. People with active infection had much higher antibody levels than those without, suggesting antibodies may help identify areas where transmission is still occurring. Our findings show that antibody testing can add valuable information to current monitoring approaches and may help programmes better judge whether treatment is working. This is especially important at a time when funding for disease-specific surveillance is limited, and integrated approaches are increasingly needed to protect elimination gains.

BackgroundTrypanosoma rangeli is a non-virulent hemoflagellate protozoan parasite that infects mammals, including humans, in Central and South America. It is primarily transmitted through the bites of triatomine bugs and shares an overlapping geographical distribution with T. cruzi, as well as triatomine vectors and mammalian hosts, and various shared surface antigens. The life cycle of T. rangeli differs from those of other human-infecting trypanosomes, such as T. cruzi and T. brucei, and the molecular mechanisms underlying host-parasite and host-vector interactions are not well understood, demanding improved molecular and genomic resources. ResultsThe use of a hybrid approach to sequence and assemble the T. rangeli genome, complemented by transcriptomics and proteomics for functional gene annotation, led to the generation of the near-complete genome sequence of the parasite. Detailed intra- and inter-specific comparative genomics allowed analysis of polymorphisms, genome structure and improved resolution of genes coding for important surface molecules such as Mucins, TASV and GP63. ConclusionsThe improved T. rangeli genome assembly, combined with comparative genomics has yielded novel biological insights. These included the first description of a metalloprotease activity, attributed to specific GP63 genes that are absent in Leishmania species. In addition, a TASV gene family that is absent in T. cruzi was identified, which indicates a possible role in the T. rangeli infection process.

There is an ongoing Oropouche Fever (OF) outbreak in Brazil since 2024. There are dengue and chikungunya prediction models available, but none to help discriminate dengue, chikungunya, and OF. Objective: This study aims to develop and validate clinical prediction models for dengue, chikungunya, OF. Methods: This study uses surveillance data from Espirito Santo state / Brazil, from 2023-2025. Epidemiological investigations and biological samples were used to conclude cases as either (a) clinical-epidemiologically confirmed, (b) laboratory confirmed, or (c) discarded. The predictors were all data related to signs, symptoms, and comorbidities available in the notification forms. The analysis was performed using random forest regression models, one for each outcome, in development and validation datasets. Results: A total of 465,280 observations were analyzed, 261,691 dengue cases (56.6%), 18,676 chikungunya cases (4.0%), 12,174 OF cases (2.6%), and 179,115 discarded cases (38.6%). All three models had good discrimination and moderate to good calibration after scaling prediction. The models retained from 26 to 16 predictors each. Leukopenia and vomiting were the most discriminatory predictors for dengue, arthritis, arthralgia, and rash were the most discriminatory for chikungunya, and epidemiological features were the most relevant for OF. The dengue, chikungunya, and OF models had ROC AUC of 0.726, 0.851, and 0.896 in the validation set, respectively. Conclusion: This research identified predictors most discriminative between dengue, chikungunya, and OF. We developed and validated predictive models, one for each condition, with moderate to very good performance available at https://pedrobrasil.shinyapps.io/INDWELL/. One may use them in diagnostic work-up and arbovirus surveillance.

BackgroundTesting blood samples with multiplex bead assays can assess elimination and identify residual foci of transmission for multiple pathogens simultaneously. In Ecuador, onchocerciasis and yaws are presumed eliminated, and the status of trachoma is unknown. We assessed their elimination status by measuring IgG antibodies in children 6-24 months. MethodsIn a birth cohort of 404 children measured between 2021-2024 in Esmeraldas province, Ecuador, we tested dried blood spots at ages 6, 9, 12, 18, and 24 months using a multiplex IgG assay that included antigens to Onchocerca volvulus (Ov16), Treponema pallidum (rp17, tmpa), and Chlamydia trachomatis (Pgp3, Ct694). We estimated seroprevalence and incident seroconversion rates across an urban-rural gradient. ResultsOf 404 children enrolled, 370 contributed 1,606 samples. Seroprevalence was near zero for onchocerciasis (0.4%, 95% CI: 0.2% to 0.8%) and yaws (0.2%, 95% CI: 0.0% to 0.5%). Conversely, C. trachomatis Pgp3 seroprevalence increased along the urban-rural gradient from Esmeraldas city (3.4%, 95% CI: 1.8% to 5.8%) to remote, river-accessible rural villages (22.4%, 95% CI: 16.0% to 30.1%), and incident seroconversion was common in rural villages (16.1 per 100 child-years, 95% CI: 11.3 to 21.9). ConclusionsSerologic surveillance found no evidence of O. volvulus or T. pallidum transmission, consistent with elimination. High Pgp3 seroconversion rates suggest ongoing C. trachomatis transmission in rural villages. Results highlight the value of integrated serologic surveillance and motivate in-depth trachoma surveillance in Esmeraldas. Lay SummaryAntibodies measured in blood provide a sensitive measure of past infection. At the population-level, antibody responses are widely used to monitor pathogen elimination. Antibodies measured in blood samples from children along an urban-rural gradient in Ecuador showed no evidence of exposure to the pathogens that cause onchocerciasis or yaws, confirming their continued elimination in the region. However, antibody responses to chlamydia were common among children in rural villages during their first two years, motivating additional surveillance to assess trachoma endemicity in the area as its endemicity status is currently unknown. Trachoma is caused by ocular chlamydia infection, and these results indicate a need for additional surveillance to assess ocular infections and clinical signs of trachoma in this population.

Human leptospirosis is a disease of public health importance in Thailand, but the animal species involved in the transmission cycle have not been fully uncovered. This study investigated Leptospira infection in dogs and terrestrial micromammals in rural Nan Province, Thailand, and the pathogen diversity. Sera from 95 seemingly healthy dogs and kidney samples from 399 micromammals were analyzed using real-time PCR for Leptospira detection, followed by conventional PCR and sequencing of infecting Leptospira. We investigated environmental factors associated with Leptospira infection in micromammals, using data collected during trapping. Real-time PCR revealed ongoing infection in 8.4% (8/95) of dogs and 10.0% (40/399) of terrestrial micromammals, with 12 infected species including Bandicota indica, Berylmys berdmorei, Berylmys bowersi, Mus cervicolor, Mus cookii, and Hylomys suillus. In this qPCR-positive micromammals, three pathogenic Leptospira species were identified: L. interrogans, L. weilii, and L. borgpetersenii. This represents the first confirmed detection of L. weilii in rodents in Thailand. Infected micromammals were found in agricultural and forest habitats but not in human settlements. Our study demonstrates potential complex leptospirosis epidemiology in rural Thailand, with multiple species serving as pathogenic Leptospira reservoirs across diverse habitats, and some shared pathogen diversity with human leptospirosis cases in Thailand. Free-roaming dogs may serve as bridge hosts, transmitting zoonotic Leptospira from micromammals to humans by visiting both animal habitats and human settlements. These findings emphasize the need for integrated One Health surveillance approaches to control leptospirosis in rural communities.