PLOS Neglected Tropical Diseases

Introduction Schistosomiasis is one of the most pervasive neglected tropical diseases in sub-Saharan Africa as an acute and chronic disease. It presents significant public health challenges in both Madagascar and Burkina Faso. Though schistosomiasis is a high prevalence disease, the understanding of its economic burden is limited. Methods A case control study was designed to compare the out-of-pocket costs and productivity loss associated with infection. A patient-specific survey questionnaire for Cost of Illness and Health-Related Quality of Life was developed and applied in Madagascar and Burkina Faso. Multiple interviews were conducted to capture the costs incurred during the entire period of illness. Results A total of 371 participants were enrolled in this study: 224 in Madagascar and 147 in Burkina Faso. The average economic burden for individuals confirmed to be negative for schistosomiasis was US$ 6.4 in Madagascar and US$ 29.8 in Burkina Faso. For mild cases, average costs were US$ 8.4 and US$ 13.5, respectively. Severe cases with complications due to schistosomiasis incurred substantially higher costs, averaging US$ 60.0 in Madagascar and US$ 1,272 in Burkina Faso. Median Health-Related Quality of Life was significantly lower among severe cases compared with controls and mild cases. Conclusions The cost of illness for schistosomiasis is significant in both countries. This study indicates the potential economic burden of disease in Madagascar and Burkina Faso, where the existing evidence on schistosomiasis is limited. Our study can help decision makers set health policy priorities.

Tungiasis, a parasitic skin disease affecting millions across sub-Saharan Africa, remains one of the most neglected tropical diseases despite its substantial morbidity and socioeconomic burden. However, effective tools for identifying high risk populations and guiding targeted interventions remain critically limited. This study developed and evaluated an interpretable machine learning framework to predict household-level tungiasis risk in Western Kenya and identify the factors driving disease occurrence. Household level data from 5,876 households across five counties were used to train and validate six supervised machine learning algorithms. Model performance was evaluated using accuracy, precision, recall, F1 score, and the area under the receiver operating characteristic curve (AUC ROC), with 95% confidence intervals (CIs) estimated for all performance metrics. Explainable artificial intelligence techniques; SHapley Additive exPlanations (SHAP) and Local Interpretable Model-Agnostic Explanations (LIME) were applied to interpret model predictions. Random Forest achieved the highest point estimates for predictive performance (accuracy = 0.594, 95% CI: 0.559, 0.627; AUC ROC = 0.611, 95% CI: 0.574, 0.647), followed closely by Logistic Regression (accuracy = 0.578, 95% CI: 0.546, 0.609; AUC ROC = 0.608, 95% CI: 0.571, 0.643), with substantial overlap in confidence intervals across the leading models. Although overall predictive performance was moderate, considerable within county heterogeneity was observed (standard deviations: 0.122, 0.134), indicating that tungiasis risk is highly localized rather than uniformly distributed. Household income, rainfall, elevation, humidity, soil moisture, housing quality (particularly earthen floors), and footwear behavior were consistently identified as the strongest predictors of tungiasis risk. By integrating machine learning with explainable artificial intelligence, this study demonstrates that complex environmental, socioeconomic, and behavioral determinants of tungiasis risk can be identified and interpreted at both the population and household levels, providing actionable insights for targeted surveillance. While further validation and calibration are needed before operational deployment, this study provides a reproducible and interpretable framework that can support evidence-based surveillance and targeted control strategies in tungiasis-endemic settings.

Background: Leptospirosis causes around 1 million cases and 60,000 deaths globally annually, predominantly affecting flood-prone tropical regions. Transmitted through contact with water or soil contaminated by animal urine infected with Leptospira spp., this bacterial zoonosis is classified as a high-risk Group B infectious disease in Vietnam. However, epidemiological and clinical data are scarce, particularly in pediatric populations. This study evaluated clinical and laboratory characteristics of leptospirosis cases at the National Children's Hospital, Hanoi, from January 2023 to August 2025. Methodology : All children admitted with probable or confirmed leptospirosis were enrolled. Clinical and laboratory data were analyzed to characterize disease manifestations and identify risk factors for severe leptospirosis. This was defined by the presence of organ dysfunction, including liver or renal failure, hemorrhage (particularly pulmonary), aseptic meningitis, cardiac arrhythmias, pulmonary insufficiency, or hemodynamic collapse. Principal Findings : Of 84 patients (37 confirmed, 47 probable), the mean age was 9.4 years, with 52.4% male and over half aged [≥] 10 years. Fever was the most common presenting symptom (85.7%); gastrointestinal and renal manifestations were frequent, including oliguria in 26.2% of cases. Key laboratory abnormalities included elevated D-dimer (81.8%), elevated C-reactive protein (75.6%), hypoalbuminemia (74.3%), increased liver enzymes (AST 63.3%, ALT 53.2%), and renal impairment ({approx} 46%). Severe disease developed in 48.8% of patients, most frequently as acute kidney injury. Hematuria was independently associated with increased severity (OR = 4.89). Conversely, fever, higher baseline albumin, and longer symptom duration prior to hospitalization were associated with a significantly reduced risk of severe disease. Conclusions : Pediatric leptospirosis in this cohort frequently presented with systemic inflammation and multi-organ involvement, particularly renal impairment. Nearly half the patients developed severe disease. Early recognition of renal signs, especially hematuria, and careful monitoring of albumin levels are critical to identifying children at risk for severe progression and optimizing clinical management.

Background: Cutaneous leishmaniasis (CL) remains a major neglected tropical disease in Afghanistan; however, recent nationwide evidence on its geographical and temporal distribution is limited. This study assessed the reported burden, spatial distribution and seasonal variation of cutaneous leishmaniasis across Afghanistan during 2024. Methods: A nationwide retrospective ecological study was conducted using aggregated routine surveillance data obtained from the National Malaria and Other Vector-Borne Diseases Program. All cases reported from government health facilities across Afghanistans 34 provinces between 1 January and 31 December 2024 were included. Reported incidence rates were calculated per 10,000 population using national and subnational population estimates. Cases were analyzed by surveillance classification, province, city, rural district, month, and season. Results: A total of 87,245 cases were reported during 2024, corresponding to an overall incidence of 25.1/10,000 population. Anthroponotic and zoonotic CL accounted for 80,202 (91.9%) and 7,043 (8.1%) cases, respectively. Jowzjan recorded the highest provincial incidence (105.0/10,000), while Kabul and Herat contributed the largest absolute numbers of cases. Shiberghan had the highest urban incidence, whereas Panjwai, Ghoryan and Hazrat-e-Sultan recorded exceptionally high rural rates. May had the highest monthly burden, while August had the lowest. Autumn accounted for the largest seasonal proportion (27.92%), whereas summer had the lowest burden (16.98%). Considerable incompleteness in district-level reporting was observed. Conclusion: CL constituted a substantial but highly concentrated public health burden in Afghanistan during 2024. Strengthened surveillance, improved diagnostic confirmation and geographically targeted case-management and vector-control interventions are particularly needed in identified high-burden provinces, cities and rural districts.

Background Tsetse are vectors of trypanosomes responsible for African animal trypanosomosis (AAT) and human African trypanosomiasis (HAT). While Cote dIvoire has successfully eliminated HAT as a public health problem and approaches elimination of transmission, AAT remains a major obstacle to agriculture and livestock production. Understanding the spatial distribution of tsetse is essential for prioritizing and sustaining disease control and elimination efforts. Methodology/Principal Findings Using 1,702 occurrence records from the national tsetse atlas we modeled the habitat suitability of the nine tsetse species present in Cote dIvoire. We identified suitable habitats in unsampled areas and quantified environmental constraints on tsetse distribution. Resampling the data to a 1km x 1km grid produced spatially explicit outputs at a resolution more relevant for operational planning. An ensemble modeling approach was employed integrating four algorithms--Random Forest, XGBoost, Maximum Entropy (MaxEnt), and Generalized Additive Models (GAM)-- with satellite-derived environmental and anthropogenic predictors--which achieved high predictive accuracy, area under the curve and True Skill Statistics 0.80 and 0.83, respectively. Distance to waterbodies, soil moisture, distance to protected areas, maximum land surface temperature, and sheep density were key drivers of habitat suitability. Importantly, the models identified suitable habitats in 11 administrative regions not covered by the atlas, providing an improved national tsetse risk profile. Conclusions/Significance These results provide a detailed assessment of the ecological suitability of tsetse across Cote dIvoire and their persistence in agroecological mosaics with high human and livestock densities. We offer a high-resolution blueprint for vector and disease control, particularly in areas where field data are currently lacking. We provide a robust framework for evidence-based decision-making within the Progressive Control Pathway (PCP) for AAT by enabling the identification of priority areas and resource allocation optimization to improve livestock productivity through more effective AAT control and reduce the risk of resurgence of HAT.

Background Scrub typhus, an acute bacterial infection caused by Orientia tsutsugamushi, is an important, under-recognized etiology of febrile illness in South Asia. Accurate surveillance for scrub typhus in Nepal is challenging due to non-specific symptoms and limited diagnostic tools. Methods We conducted a representative school-based cross-sectional serosurvey in Kavrepalanchok and Dolakha, Nepal between November 2021 and April 2022 using two-stage sampling, we randomly selected 13 public schools and then up to 100 children aged 4-18 years per school. We collected capillary blood samples and tested for IgG responses to Orientia tsutsugamushi-derived recombinant 56-kDa antigen using commercially available ELISA kits. We estimated seroincidence rates using previously-published models of antibody decay dynamics from confirmed scrub typhus cases. We compared seroincidence to seroprevalence estimates using cutoffs derived from Gaussian finite mixture models applied to the study population. Results We enrolled a total of 827 children (participation rate: 94.8%). The median age was 10 years (IQR: 8-13), and 53.08% of the participants were female. The overall seroincidence rate was 6.3 new infections per 1000 person-years (95% CI: 4.7- 8.4), and the rate was slightly higher in peri-urban Kavrepalanchok (7.3; 95% CI: 4.9 - 10.3) compared with rural Dolakha (5.3; 95% CI: 3.3 - 8.5). Seroincidence increased with age, from 3.6 new infections per 1000 person-years (95% CI: 1.4- 9.7) among children aged 4- 7 years to 9.4 (95% CI: 6.2-14.3) among children aged 14-18 years. Seroincidence was higher in females (8.3; 95% CI: 5.9 -11.8) than in males (4.1; 95% CI: 2.4 - 6.9) (p=0.02). The overall seroprevalence was 6.5% (95% CI: 4.9-8.4) and followed a similar age and geographic trend to the seroincidence rate. Discussion Our findings reveal a substantial burden of pediatric scrub typhus in the Kavrepalanchok and Dolakha districts of Nepal. Seroincidence increased with age and was higher among females. School-based serosurveys offer an efficient sampling frame to rapidly assess population-level scrub typhus transmission intensity among children and adolescents, though may not represent out-of-school populations.

Background Paragonimiasis is a neglected tropical disease (NTD) and of significant public health concern in northeastern India where it is frequently misdiagnosed as pulmonary tuberculosis. Transmission occurs through consumption of raw or undercooked freshwater crustaceans, a widespread dietary practice in this region. Accurate diagnosis will ensure cheap, effective treatment with praziquantel and avoid unnecessary prolonged tuberculosis therapy. This study determines the prevalence, specific risk factors for infection, and showcases a clinical scoring model to screen for active paragonimiasis in endemic areas. Methodology/Principal Findings A community-based cross-sectional survey was conducted in Medziphema block, Nagaland, in northeastern India screening 2,942 residents aged over 10 years. Participants reporting chronic cough ([≥]2 weeks) provided sputum and serum samples (93,3.16%). Sputum examination was screened for Paragonimus ova and acid-fast bacilli, and serum samples were tested for IgG antibodies against Paragonimus heterotremus using anti-Extra Secretory antigen by ELISA (positive case defined as titre [≥]0.5 IU). IgG-confirmed paragonimiasis was detected in 30 individuals, yielding a population prevalence of 1.02% (30/2942) and 32.3% (30/93) amongst symptomatic participants. Sputum microscopy demonstrated limited sensitivity (3.3%), detecting cysts in only one confirmed case. Tuberculosis co-infection was documented in 6.7% of sero-positive cases. Multivariable regression identified significant associations with increasing age (adjusted (aOR) 1.04) previous tuberculosis history (aOR 4.62), monthly snail consumption frequency (aOR 1.05), ever smoking (aOR 3.51), and education beyond middle school (aOR 2.93). Haemoptysis (aOR 9.86) was the strongest symptomatic predictor. Clinical scoring models were developed, with haemoptysis consistently emerging as the most robust predictor across all models. Conclusions/Significance Pulmonary paragonimiasis constitutes a prevalent yet under-recognised condition in several southeast-Asian communities, necessitating systematic screening as a differential diagnosis for pulmonary tuberculosis. The clinical scoring model facilitates early case identification in resource-constrained settings. Public health interventions must address dietary practices, particularly consumption of raw or undercooked freshwater crustaceans, to interrupt transmission.

Background: Human Tungiasis is a neglected tropical skin disease caused by the sand flea Tunga penetrans, associated with pain, inflammation, secondary bacterial infections, and significant morbidity. Despite its health impact on school children, it remained understudied in Kamushoko Parish, Bubaare Sub-County, Mbarara District, Uganda. Objectives: To determine the prevalence and identify associated factors of human Tungiasis among primary school children in Kamushoko Parish, Bubaare Sub-County, Mbarara District. Methods: A school-based cross-sectional descriptive study was conducted among 415 primary school children (P1-P7) at Katooma II and Komuyaga Primary Schools in March 2026. A census sampling approach enrolled all eligible pupils. Data were collected through structured face-to-face questionnaires and clinical examination of exposed areas. Tungiasis diagnosis was based on clinical identification of characteristic lesions with microscopic confirmation of extracted specimens. Bivariate and multivariate logistic regression analyses identified independently associated factors. Results: Of 415 children examined, 22 had active Tungiasis lesions, yielding an overall prevalence of 5.3% (95% CI: 3.53%-7.90%). Katooma II Primary School recorded a slightly higher prevalence (6.29%) than Komuyaga Primary School (4.78%), though the difference was not statistically significant (p = 0.499). Male children had higher odds of infection than females (7.1% vs. 3.7%). Children aged 9-10 years had the highest prevalence (7.7%). In the multivariate logistic regression, walking barefoot at school was the only independently significant predictor of infection (aOR = 0.18 for home vs. school; 95% CI: 0.04-0.78, p = 0.022). Conclusion: The prevalence of Tungiasis among primary school children in Kamushoko Parish was 5.3%, confirming ongoing transmission in the community. Walking barefoot at school was the only independent predictor of infection, highlighting the school environment as a critical intervention site. School-based strategies including grounds improvement, routine classroom cleaning, enforcing no-barefoot policies, and health education are recommended.

Background: Case fatality reflects the quality and timeliness of clinical care for leptospirosis, yet no study has examined it at a national level in the Dominican Republic (DR), where leptospirosis is endemic. We describe the case fatality rate (CFR) of leptospirosis in the DR between 2012 and 2026 and identify associations with mortality. Methods: We conducted an analytical cross-sectional study, using national surveillance records merged with a discharge-condition extract via a composite key. We calculated CFR with Wilson 95% confidence intervals among 5,412 valid cases (suspected, probable, or confirmed) reported from January 2012 through June 2026. We compared proportions with Pearson's chi-square test, assessed annual trend with ordinary least squares linear regression, and fitted multivariable logistic regression models to account for confounding. Results: Overall CFR was 8.5% (460/5,412), with no significant annual trend (p=0.372). CFR was higher in men than women (p < 0.001) and increased significantly with age (p < 0.001). Male gender (OR: 1.79; 95%CI: 1.18-2.73) and pre-existing comorbidity (OR: 1.76; 95% CI: 1.21- 2.57) were independent predictors of death. Clinical complications were the strongest predictor in the adjusted model (OR: 3.16; 95%CI: 2.17-4.61), attenuating the gender effect. CFR varied widely by province (2.43-22.22%) and correlated negatively with incidence at the province level (p = 0.066). Conclusions: Leptospirosis case fatality is concentrated among men, people with comorbidity, and those who develop clinical complications. These national, long-term findings can help prioritize clinical and surveillance resources as extreme weather events are expected to intensify across the Caribbean.

Background Accelerated efforts to eliminate lymphatic filariasis (LF) as a public health problem have been supported by the introduction of the triple-drug regimen of ivermectin, diethylcarbamazine and albendazole (IDA) in endemic settings. In Sao Tome and Principe, nationwide mass drug administration (MDA) with diethylcarbamazine and albendazole was implemented in 2018, followed by IDA in 2019 and 2020. This study assesses progress towards elimination using post-MDA impact assessment surveys conducted after cessation of treatment. Methods Cross-sectional surveys were conducted among adults aged 20 years and older in 2022 and again between December 2024 and January 2025. Circulating filarial antigen (CFA) was detected using the filarial test strip (FTS). Individuals who tested positive were examined for microfilaremia using nocturnal calibrated thick blood smear microscopy. Additionally, programme data on MDA coverage and morbidity were obtained from national surveillance records. Results Three rounds of nationwide MDA achieved high epidemiological coverage (86.4% in 2018, 74.2% in 2019 and 80.0% in 2020). The impact assessment surveys conducted in 2022 evaluated 14 132 adults, with 21 individuals (0.15%) testing positive for CFA, while the follow-up survey conducted between December 2024 and January 2025 assessed 14 653 adults and detected seven positive cases (0.05%). No microfilariae were detected among the 28 antigen-positive individuals examined using nocturnal calibrated thick blood smears. National morbidity records documented 190 cases of lymphoedema and nine cases of hydrocoele. Conclusions Infection indicators remain well below WHO decision thresholds, suggesting that LF transmission is unlikely to be sustained. Sao Tome and Principe appears to be close to eliminating LF as a public health problem. However, strengthening morbidity management services will be essential to support the preparation of the national elimination dossier.

IntroductionDengue, one of the most important arboviral infections worldwide, is transmitted primarily by the mosquito Aedes aegypti, a vector closely associated with human habitations. Because vector control is the primary prevention strategy for this disease novel tools are urgently needed. We evaluated an Attractive Lethal OviTrap (ALOT) that targets epidemiologically relevant gravid female mosquitoes for public health impact against dengue disease. MethodsWe conducted a proof-of-concept field efficacy trial in the Amazonian city of Iquitos, Peru, to quantify the reduction of vector density, parity, and sex ratio and symptomatic human dengue infection over a 3.5 year follow-up period. After three baseline entomological surveys in core (753 houses), and buffer (1,549 houses) areas where traps were placed in and around homes, and a control (1,233 houses) area without traps, entomological surveys were carried out every 2 months, and household residents were monitored for dengue disease 3 times a week. Trap maintenance was conducted at 2-3 week intervals by study staff during the first 2.5 years and by residents in the final year. ResultsTotal and female Ae. aegypti abundance demonstrated a strong initial effect with 52% and 47% fewer mosquitoes after trap placement, respectively (Total: RR = 0.48, 95% CI: 0.40 - 0.58, p < 0.001; Females: RR = 0.53, 95% CI: 0.43 - 0.66, p < 0.001). The effect diminished significantly, however, over the study period (interaction coefficient = 0.035 per month, p < 0.001; interaction coefficient = 0.030 per month, p < 0.001). Female-to-male ratio decreased after trap deployment and impact on non-Aedes abundance was like that of Aedes. Cumulative symptomatic dengue incidence was 1.40% (95% CI: 1.00%-1.70%) in the ALOT area versus 3.20% (95% CI: 2.60%-3.80%) in the control area, a 56% relative reduction (log-rank {chi}{superscript 2}=30.0, p<0.001). Restricted mean survival time analysis showed participants in the intervention area on average remained dengue-free for 15.5 additional days (95% CI: 11.1-20.0, p<0.001). ConclusionsThe ALOT strategy functioned as predicted, decreasing but not eliminating female vector densities, with a clear public health impact, lowering dengue disease in areas where traps were deployed. Our study also illustrates the challenges associated with conducting large-scale vector control trials and the need to consider programmatic implementation early in the process of bringing a new product to market. Author SummaryDengue is one of the most important mosquito transmitted infections worldwide. Aedes aegypti, the most important species involved, has a unique biology living in containers associated with households. New methods to control this mosquito are needed and we present our evaluation of a novel trap called the Attractive Lethal OviTrap (ALOT) that targets older female mosquitoes that are the most important for dengue disease transmission. We conducted a trial in the Amazonian city of Iquitos, Peru, to measure reductions in mosquito numbers, age, and sex ratio and symptomatic human dengue infections over a 3.5 years. After baseline entomological surveys prior to placing ALOT traps in homes in a treatment area, which included a central core area with 753 houses and a protective buffer area with 1,549 houses areas. We also had a control area without any traps in 1,233 houses. Mosquito surveys were carried out every 2 months, and household residents were monitored for dengue disease 3 times per week. Trap maintenance was conducted at 2 - 3 week intervals by study staff during the first 2.5 years and by residents in the final year. The number of all Ae. aegypti were initially reduced by 52% after trap placement whereas females were reduced by 47%. The effect diminished significantly, however, over the study period. Female-to-male ratio decreased after trap deployment and impact on other mosquito species was like that of Aedes. Dengue incidence was 56% less in the area with traps compared to the control area, estimating that participants in the intervention area on average remained dengue-free for 15.5 additional days. The ALOT strategy functioned as predicted, decreasing but not eliminating female mosquitos and had a clear public health impact, lowering dengue disease in areas where traps were deployed. Our study also illustrates the challenges associated with conducting large-scale vector control trials and the need to consider programmatic implementation early in the process of bringing a new product to market.

The World Health Organization (WHO) validated Sri Lanka had eliminated lymphatic filariasis as a public health problem in 2016, the second country in Southeast Asia to attain this status. However, post-validation surveillance has identified sporadic cases of brugian filariasis. The reemergence of Brugia malayi infections in Sri Lanka warrants urgent investigations. Recent studies have shown that the parasite responsible for the reemergence is a novel zoonotic Brugia sp. maintained among dogs that is closely related but distinct to the human-infecting B. malayi species. The current study employed morphological and morphometric assessments, revealing that this novel zoonotic Brugia sp. is within the B. malayi morphological range. Molecular characterization of three genomic regions, the nuclear genomic region SLXI, the non-coding region HhaI, and the mitochondrial genomic region COXI confirmed it as a genetic variant more closely related to B. malayi than to B. pahangi. Phylogenetic analysis further indicated it as a distinct genomic variant, closely related to a B. malayi-like parasite reported from India. Notably, that same parasite was identified in infected humans, animals, and potential vector mosquitoes. This, together with the detection of both human and animal blood within the same brugian infective mosquitoes, and delineating the canine origin of the parasites in human infections, provides compelling evidence supporting zoonotic transmission of this parasite. To our knowledge, this is the first report demonstrating the presence of the same brugian parasite in humans, domestic animals, and potentially infective mosquitoes in Sri Lanka, supported by multi-genomic evidence. The recent identification of multiple potential mosquito vector species suggests that this parasite may have undergone adaptive changes, facilitating its ability to overcome the species barrier. These findings substantiate the long-held hypothesis of zoonotic transmission of the reemerged brugian parasite, highlighting significant implications for ongoing surveillance and control strategies.

Gambiense human African trypanosomiasis (gHAT) is a vector-borne disease, spread by tsetse, found in West and Central Africa. It has been targeted for elimination of transmission (EoT) by the World Health Organization: the reduction to zero of the incidence of infection, with minimal risk of reintroduction. Many high-risk regions have implemented vector control (VC), in addition to medical interventions, to reduce the spread of gHAT and reach EoT. There exists uncertainty around the effectiveness of VC interventions, and so the impact of VC can be measured through deploying traps, which estimate changes in the tsetse population. In this study, we use mathematical transmission modelling to assess the added monetary value of entomological monitoring data in strategy selection for two health zones of the Democratic Republic of Congo, illustratively chosen because of their different levels of uncertainty on VC effectiveness. We used active adaptive management (AAM) - the process of updating our strategy based on collected data (i.e. choosing to continue or stop VC based on perceived effectiveness), where posterior distributions on VC effectiveness were calculated with an adaptive MCMC method. Next, we used an established gHAT transmission model along with the policy objective of maximising the intervention's net monetary benefit to calculate the value gained by various monitoring strategies. We found that the strategy that included VC and twice-yearly entomological monitoring was cost-effective at a willingness to pay threshold of $153 for the health zone of Mulumba, where we were able to determine the optimal monitoring strategy, but it was not cost-effective in the health zone of Vanga. This study is the first application of AAM to monitoring data for a vector-bone infection, presenting a novel framework for quantitative assessment of how VC monitoring could be used to improve the cost-effectiveness of interventions in other regions.

BackgroundLymphatic filariasis (LF), caused by Wuchereria (W) bancrofti, Brugia malayi and Brugia (B) timori, remains a major public health problem known for its disfiguring and debilitating effects despite notable progress under the Global Program to Eliminate Lymphatic Filariasis (GPELF). Following recent national directives (2024) restructuring implementation units (IUs) to the block level, all TAS-cleared blocks now require re-evaluation using night blood surveys (NBS) or filarial test strip (FTS) kits. Molecular Xenomonitoring (MX) is recommended as a post-validation surveillance method for detecting active LF transmission in vectors. Therefore, an exploratory study was conducted in two coastal districts of Odisha, namely Jagatsinghpur and Puri, which cleared TAS-III, to investigate the presence of B. malayi and W. bancrofti infections in filaria-transmitting vectors. Methodology/Principal FindingsAdult female mosquitoes were collected from three villages across Jagatsinghpur and Puri districts during March-April 2025. Species were identified morphologically, segregated and pooled. The pooled samples were screened for the presence of filarial DNA using species-specific PCR assays. Of 1,518 collected adult female mosquitoes, 22.6% were Culex quinquefasciatus, 18.3% were Mansonia (Mn) annulifera, and 4.3% were Mansonia uniformis. Among 33 pools screened, six pools were positive for B. malayi DNA (18.18% pool positivity; infection rate 2.88%, 95% CI: 1.23-5.74), in Mn. annulifera, whereas W. bancrofti was not detected. Conclusions/SignificanceThe study provides the first molecular confirmation of B. malayi infection in Mn. annulifera, indicating a persistent Brugian transmission in Odisha even after the implementation of mass drug administration. The Study highlights MX as a sensitive, non-invasive surveillance tool for detecting residual infection in post-MDA and post-TAS settings. The study underscores the need for a standardized MX protocol and integration with entomological monitoring to sustain national LF elimination targets by 2027. Author SummaryLymphatic filariasis is a mosquito-borne disease that can cause severe, disfiguring swelling of the limbs and other lasting disabilities, and it remains a serious public health problem in India. National programmes in India are actively working to eliminate it by giving preventive medicines to communities, conducting surveys to confirm that transmission has ceased, and once an area passes, this treatment is withdrawn. However, it is not always clear whether the parasite has truly disappeared or is still lingering at very low levels. In this study, we searched for the parasite directly inside mosquitoes, an approach that does not require collecting blood from people. We sampled mosquitoes from two coastal districts of Odisha, India, that had already passed the required surveys and stopped treatment. We found the parasite Brugia malayi in Mansonia mosquitoes, the first time this has been shown using this molecular method in the region, although the more common filarial parasite was not detected. Our findings show that transmission can smoulder on even after an area is judged free of disease. Because India has no available rapid field test for this particular parasite, we argue that examining mosquitoes should become a routine safeguard for the countrys elimination effort.

Background Urogenital schistosomiasis control programmes have traditionally focused preventive chemotherapy (PC) on school-aged children (SAC, 5 -14 years). However, the burden of infection among pre-school-aged children (Pre-SAC) and the extent to which infection patterns differ from those of adults remain poorly documented in the Lake Chad Basin. This study presents a secondary analysis of routinely collected programme data from the Dawa Mobile Health schistosomiasis control programme to characterise the burden, age distribution, and determinants of urogenital schistosomiasis among children and adolescents (1 - 20 years) in the Ngouri Health District, Chad. Methods We conducted a retrospective cross-sectional secondary analysis of routinely collected data collected during a community-based schistosomiasis control programme implemented in the Ngouri Health District, Lac Province, Chad, between February 2024 and April 2025. All individuals screened during routine programme activities were eligible for inclusion. Children and adolescents aged 1- 20 years (n = 1,946) constituted the primary population of interest, while adults aged [&ge;]21 years (n = 2,570) served as a comparison group. Urogenital schistosomiasis was diagnosed by urine membrane filtration, with infection defined as the detection of at least one Schistosoma haematobium egg per 10 mL of urine. Multivariable logistic regression was used to identify factors independently associated with infection among children and adolescents. Results Among 4,516 programme participants, children and adolescents represented 43.1% of those screened and accounted for 43.9% of the 880 confirmed infections. During programme implementation, the observed prevalence was 19.8% (95% CI: 18.1 - 21.7%) among children and adolescents, 18.2% (95% CI: 14.7 - 22.2%) among Pre-SAC (1 - 10 years), and 20.3% (95% CI: 18.3 - 22.4%) among SAC (11 - 20 years), with no significant difference compared with adults (19.2%; p = 0.633). Both child age groups remained within the WHO moderate-endemicity category, indicating continued eligibility for annual preventive chemotherapy. In multivariable analysis, neither age subgroup, sex, education level nor occupation was independently associated with infection (all p > 0.05), suggesting broadly distributed community exposure. Conclusions Pre-school-aged children experienced a burden of urogenital schistosomiasis comparable to that of school-aged children and adults in this agro-pastoral setting. Although the reported prevalence reflects infection observed during programme implementation rather than baseline district prevalence, moderate endemicity persisted after 15 months of community-based screening and treatment, supporting the continuation of community-wide preventive chemotherapy, including Pre-SAC. These findings also suggest that chemotherapy alone may be insufficient to interrupt transmission and highlight the need to complement treatment with strengthened WASH interventions and adaptive surveillance strategies capable of identifying persistent transmission hotspots. Keywords: Schistosoma haematobium; urogenital schistosomiasis; pre-school-aged children; school-aged children; preventive chemotherapy; mass drug administration; community-based control; Lake Chad; Chad; Dawa Mobile Health.

Abstract Background: Urogenital schistosomiasis remains a major neglected tropical disease in rural communities, particularly in reservoir-adjacent settings where sustained human-water contact facilitates persistent transmission. Despite ongoing control efforts, communities located around reservoirs may experience persistent transmission partly due to socioeconomic water exposure and presence of infected intermediate host snails in aquatic habitats. This study assessed the prevalence, intensity, and epidemiological correlates of Schistosoma haematobium infection in reservoir-adjacent communities in Kano State, Nigeria to better understand local transmission. Methods: A community-based cross-sectional study was conducted among 447 consenting participants from six communities located around three water reservoirs in Kano State. Sociodemographic characteristics, water-contact behaviour, sanitation practices, treatment-seeking behaviour, and knowledge related to urogenital schistosomiasis were obtained using interviewer-administered questionnaires. Urine samples collected between 10:00 and 14:00 were examined using microscopy following centrifugation/sedimentation. Schistosoma haematobium isolates were characterised by molecular methods, using PCR and Sanger dideoxy sequencing. Bulinus snails were collected from the reservoirs by handpicking and scooping methods. Nucleotide sequences were analysed using NCBI BLAST to confirm species identity. Epidemiological data on Schistosoma haematobium infection were analysed using chi-square tests and univariate and multivariate logistic regression analyses to assess associations with explanatory variables. Results: The overall prevalence of S. haematobium infection was 34.23% (153/447), indicating moderate endemicity. Molecular study confirmed the occurrence of pure S. haematobium. Community-specific prevalence ranged from 32.35% to 37.84%. Heavy-intensity infection (>50 eggs/10 mL urine) occurred in 17.65% of infected participants. Infection was most common among children and adolescents and was higher in males than females, although the sex difference was not statistically significant. Water-contact behaviour was the strongest correlate of infection: participants reporting water contact had a markedly higher prevalence than those without such exposure (39.12% vs 3.28%; OR = 18.96, 95% CI: 4.56-78.73). Fetching water (aOR = 2.57; 95% CI = 1.53 -4.34; p < 0.001) and Swimming (aOR = 2.37; 95% CI = 1.42 -3.94; p = 0.001) were the specific activities most strongly associated with higher odds of S. haematobium infection. Age (aOR = 0.91; 95% CI = 0.87 - 0.95; p < 0.001) significantly reduced the odds of infection. In terms of gender, female participants had significantly lower odds of infection compared with males (aOR = 0.52; 0.29 0.92; p = 0.03). Knowledge of transmission was poor, with only a small proportion of participants correctly identifying contact with contaminated water as the cause of infection. A rare ectopic detection of S. mansoni eggs in urine was also observed. Presence of S. haematobium-infected Bulinus intermediate hosts in the water reservoirs was reported. Conclusions: Urogenital schistosomiasis remains actively transmitted in reservoir-adjacent communities in Kano State, with infection strongly associated with frequent human-water contact and poor disease knowledge. These findings support the need for integrated control strategies combining praziquantel-based preventive chemotherapy, targeted health education, improved water and sanitation, and behaviour-focused interventions to reduce reinfection and interrupt transmission. Keywords: Urogenital schistosomiasis, Schistosoma haematobium, water reservoirs, prevalence, risk factors

Objectives: In some resource-limited settings the case-fatality rate of severe leptospirosis can exceed 50%. Early recognition of severe disease can expedite transfer to referral centres for advanced supportive care. The entirely clinical, 3-point SPiRO score can be calculated rapidly at presentation to predict a patients subsequent clinical course. In its derivation study, a SPiRO score of 0 had a negative predictive value (NPV) for intensive care unit (ICU) admission of 98% (95% confidence interval (CI): 96-99). In this validation cohort we sought to confirm the clinical utility of the SPiRO score and to compare its prognostic utility with other leptospirosis-specific and general disease severity scores. Methods: We examined consecutive adults presenting to high-caseload hospitals in tropical Australia with laboratory-confirmed leptospirosis between June 2016 and April 2026. The ability of the SPiRO score to predict requirement for ICU admission before hospital discharge was compared with that of the leptospirosis-specific QuickLepto score and commonly used disease severity scores, namely the SOFA, qSOFA, qSOFA-lactate, NEWS-2, qNEWS, UVA and the SIRS scores. Results: ICU admission was required in 62/309 (20%) episodes of leptospirosis. The SPiRO score performed as well as - or better than - all the other scores in predicting ICU admission. The Area Under the Receiver Operating Characteristic curve for the SPiRO score was 0.83 (95% CI: 0.77-0.89); only the SOFA score had a higher value: 0.84 (0.79-0.90), although the difference was not statistically significant (p=0.08). The SPiRO score had the highest NPV for ICU admission of any of the scores: 95 (95% CI: 91-97)%. Conclusions: The SPiRO score can be calculated easily at the bedside at presentation to expedite the recognition of patients with leptospirosis who are most likely to deteriorate. In resource-limited settings this entirely clinical score can also help reduce unnecessary escalation of care, optimising the use of finite health resources.

BackgroundMalaria caused by Plasmodium knowlesi and lymphatic filariasis caused by Brugia malayi are mosquito-borne infections with non-human primates as reservoirs. P. knowlesi has emerged as a significant cause of human malaria in Southeast Asia over the past two decades. Belitung district, Indonesia, was until recently assumed to have eliminated B. malayi until infections were detected in humans and long-tailed macaques. To investigate whether the local reservoir of B. malayi is also a reservoir for malaria we screened macaques from 4 areas in Belitung for malaria parasites. Methods and findingsBlood samples from 163 long-tailed macaques (Macaca fascicularis) that had been tested for B. malayi were examined by quantitative PCR assays specific for Plasmodium spp., P. knowlesi, P. inui, P. coatneyi and P. cynomolgi. A total of 130 macaques (79.8%) tested positive in the pan-Plasmodium qPCR assay. Plasmodium inui was most prevalent (41.7%), followed by P. knowlesi (38.7%), P. coatneyi (24.5%) and P. cynomolgi (13.5%). Multiple species infections, with 2-3 Plasmodium species were detected in 37% of macaques. Notably, 20 (91%) of 22 B. malayi-positive macaques were co-infected with at least one Plasmodium species. We sequenced the complete mitochondrion from 9 samples diagnosed by qPCR as mono-infections. Phylogenetic analysis confirmed 7 as P. knowlesi, and the other two as P. inui and P. coatneyi. Phylogenetic and pairwise analysis revealed that P. knowlesi isolates from Belitung were closely related to each other and to P. knowlesi from humans and monkeys from Thailand, Malaysia and Indonesia. ConclusionsMolecular evidence shows high prevalence of zoonotic malaria parasites in macaques from Belitung, emphasizing the risk of human transmission. Increased surveillance, improved diagnostics, and targeted interventions are needed to prevent zoonotic spillover of P. knowlesi as it has been observed for B. malayi in Belitung. Author summaryWe examined macaques for Plasmodium parasites in Belitung Island, Indonesia, a region classified as free of locally transmitted human malaria. Plasmodium knowlesi is a monkey parasite that commonly infects humans and has emerged as a concern in Southwest Asia over the last 20 years. In Belitung, macaques are infected with Brugia malayi, a filarial nematode, that causes lymphatic filariasis in humans. Blood samples from 163 macaques were screened for Plasmodium DNA and 80% carried malaria parasites. Plasmodium inui was most common, followed by P. knowlesi, P. coatneyi, and P. cynomolgi. Many macaques were infected with multiple parasites simultaneously, but no host was infected with all four Plasmodium species. Ninety one percent of B. malayi-positive macaques were co-infected with malaria parasites, including P. knowlesi, indicating multi-parasite infections that could potentially spread to humans. Analysis of the mitochondrial genome of 7 P. knowlesi isolates from Belitung showed that they were most similar to each other and both human and monkey samples from Malaysia, Thailand and Indonesia. The study highlights the need for enhanced malaria monitoring and prevention, given the complex epidemiology of co-infecting parasites and risk to humans and animals.

Background: Dirofilaria repens is a zoonotic parasite expanding unnoticed across Europe due to climate change. We hypothesised that in this process, the Carpathian Basin has a facilitating effect. Methods: Using 426 georeferenced European cases, the probability of infection occurrence was determined in relation to climatic factors, surface water availability, regional social deprivation, and stray dog population density. To analyse the potential impacts of ecological and social factors (deprivation and stray dog population density), the MaxEnt algorithm, and spatial Empirical Bayes smoothing and Bivariate Local Indicators of Spatial Association (BiLISA) index calculation were employed, respectively. Results: MaxEnt analysis revealed that the mean warmest month temperature (22.8 - 25.1 oC), winter mean minimum temperature (> -2.1 oC), and summer precipitation (28.6 - 231 mm) have the strongest impact on the probability of the parasite's occurrence in Europe. Social factors have significance in the eastern Balkans and the Carpathian Basin, but not in Western Europe. The Carpathian Basin appears to be a hotspot, similar to Mediterranean coastal areas. Furthermore, the Danube Valley acts as an ecological corridor for subtropical vector-borne parasites. Conclusions: Our findings confirm that summer warmth is the primary ecological driver of the parasite's range expansion, which is facilitated by the Carpathian Basin due to climatic and socioeconomic conditions.

Abstract Introduction Onchocerciasis is targeted for elimination with community-directed treatment with ivermectin (CDTI). Alternative strategies are needed in areas where transmission persists despite long-term CDTI and/or are co-endemic with loiasis. This study assessed the efficacy of 35-day treatment with 100mg doxycycline on Wolbachia density at 6 months and microfilaridermia and palpable nodules at 30 months post-treatment. Methods A treatment follow-up study was conducted in 20 high-transmission onchocerciasis communities in a co-endemic loiasis area of South-West Cameroon. Community-based directly observed treatment with 100mg doxycycline was administered to community members aged [&ge;]9 years. Wolbachia clearance at 6-months and treatment efficacy on microfilaridermia and palpable nodules were assessed at 30-months post treatment. Factors associated with reductions in microfilaridermia post treatment, including adherence to doxycycline treatment were assessed with mixed-effects logistic regression. Results Over 92% (2835/3080) of eligible participants took 35 days of 100mg doxycycline over 5 or 6 weeks. This regimen achieved a 62.8% microfilaridermia reduction and 99% palpable nodule reduction in the 720 participants included at follow-up. Wolbachia depletion was observed in 92% of skin samples at 6 months post treatment. The most important factor associated with microfilaridermia after 30 months was having missed at least 7 doxycycline consecutive doses (OR 3.11, 95%CI: 1.17-8.26). Incomplete treatment to a lesser extent was not associated with reduced efficacy at follow-up. Conclusion This large-scale community intervention shows that a 5-week treatment with 100mg doxycycline is feasible and has high curative efficacy against adult O. volvulus as measured by the dramatic reduction in the proportion of palpable nodules at 30-months post treatment. The high efficacy shows the tremendous potential of anti-Wolbachia drugs as part of the arsenal for onchocerciasis elimination and paves the way for the next generation of anti-Wolbachia drugs with shorter treatment courses, which will facilitate the implementation of alternative strategies to accelerate onchocerciasis elimination.