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: 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: 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.

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.

Background: Visceral leishmaniasis (VL) is the most severe form of leishmaniasis and is caused by parasites from the Leishmania donovani complex. VL is endemic in 54 countries, with East Africa (EA) accounting for [~]70% of the global burden. Therefore, there is a pressing need to prioritize VL research in EA. Transcriptomics analysis in rodent models and patients following treatment have shown that immune homeostasis is not restored by the end of treatment. However, comprehensive proteomic studies in VL remain scarce, and the few available studies were conducted outside EA. Methodology/Principal Findings: As a part of ImmStat@cure consortium, we used the Olink Reveal proximity extension assay to profile circulating proteins in VL patients from Ethiopia, Kenya and Sudan. By comparing patients at admission and 17 days after treatment with SSG-PM, we have identified a systemic Th1-cytotoxic inflammatory profile at admission, characterized by high abundance of IFN{gamma}, IL-1B, IL-6, and the granzymes A and B. Chemokines with high abundance included CXCL8/10/11, CCL3, CCL4, CCL8, CXCL8 and CCL20, consistent with the recruitment of monocytes, macrophages, T cells, and NK cells. There were also evidence of immune regulation/exhaustion, with high levels of PD1, PD-L2, IDO1 and KYNU. Although the immune profiles were similar at admission, country specific differences were observed after treatment. Kenyan patients exhibited a sustained inflammatory profile and signatures of myeloid recruitment, characterized by high levels of IL-1B, IL-6 , IL-12A, CXCL8, CCL2, CCL3, CCL4, CCL7 and CEBPB. Sudanese patients showed signatures associated with lymphocyte activation and immune regulation. Conclusions/Significance: These results highlight the complexity of the immune changes associated with VL, identifying both core conserved profiles at admission and country-specific profiles after treatment. The data provided here will provide a valuable resource for future comparative studies across more diverse different geographic regions, for linkage studies that assess the impact of parasite genotype on immune / metabolic response and for use during the evaluation of new therapies against VL.

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.

Dirofilariasis, or heartworm disease, is a life-threatening parasitic infection caused by the nematode parasite Dirofilaria immitis. Mosquito vectors in tropical and subtropical regions transmit the infection. Current treatment options are expensive, have a short-term effect, and depend on anthelminthic therapy. There are no licensed vaccines available for preventing heartworm infections. The primary goal of this study was to identify potential vaccine candidates, develop a tetravalent fusion protein (rDiHAVO) vaccine antigen, and evaluate its immunogenicity and efficacy in a mouse model of D. immitis infection. Results show that the rDiHAVO is highly immunogenic in mice and confers over 95% protection against a challenge infection. These findings suggest that rDiHAVO is a potential vaccine candidate against Dirofilariasis. Additional testing in dogs can advance this vaccine candidate to clinical trials.

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

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.

Objectives To assess microfilaraemia, chronic lymphatic filariasis (LF)-related morbidity, and community knowledge and self-reported preventive behaviours in a rural community in northern Ghana following prolonged mass drug administration (MDA). Design Community-based cross-sectional study. Setting Birifor community, Lawra Municipality, Upper West Region, northern Ghana, from October 2024 to January 2025. Participants A total of 261 community members aged 10 years and above were selected using random sampling and participated in the study. Outcome measures Outcome measures included microfilaraemia detected by night blood microscopy, chronic LF-related morbidity identified through clinical examination, and community knowledge and self-reported preventive behaviours assessed using a structured questionnaire. Results No microfilariae were detected (0/261; 0%). Chronic lymphoedema was identified in five individuals (1.9%), all aged over 40 years. Awareness of LF was high (95.8%), yet only 39.5% of participants demonstrated good community knowledge and self-reported preventive behaviours. Misconceptions regarding transmission, particularly beliefs that LF is hereditary or caused by spiritual factors, were common. MDA participation was high (93.1%). All five individuals with chronic lymphoedema reported loss of income, and three (60%) reported additional household income loss due to caregiving responsibilities. Conclusions No microfilaraemia was detected, suggesting very low transmission in the study area, although residual infection cannot be excluded. Chronic LF-related morbidity and gaps in community knowledge persist despite high MDA participation. Sustained surveillance using more sensitive diagnostic approaches, together with morbidity management and disability prevention, community education and support for affected households, will be important to sustain LF elimination efforts.

Introduction: Nigeria continues to report one of the highest burdens of diphtheria globally, with Kano State accounting for a disproportionate share of cases and deaths. Understanding epidemiological patterns and mortality determinants is essential for guiding targeted interventions. Objectives: To describe the distribution of diphtheria cases in Kano State by socio-demographic and clinical characteristics, Local Government Area, and month of reporting, and identify independent predictors of mortality. Methods: We conducted a retrospective cohort study of 21,369 patients with clinically compatible and laboratory-confirmed diphtheria using secondary data from medical records (2022-2025). Descriptive statistics summarized patient characteristics and disease distribution. Associations with mortality were assessed using chi-square or Fishers exact tests. Multivariable logistic regression identified predictors of mortality, reported as adjusted odds ratios (aORs) and 95% confidence intervals (CIs). Results: Of 21,369 patients, 13,557 (63%) were female, with a median age of 11 years (IQR: 7-13.6). Children aged 5-9 years accounted for 29% of cases. Prior contact with a case was reported in 2,633 (12%) patients, while 168 (1%) were laboratory-confirmed. Overall, 13,468 (63%) patients were unvaccinated and 5,381 (25%) fully vaccinated; Diphtheria antitoxin DAT was administered to 2,035 (10%). Cases occurred in all local government areas (LGAs), with four accounting for 60% of cases. Transmission occurred year-round, peaking in March 2024 and August 2023 and 2025. Overall, 1,131 deaths occurred (CFR: 5.3%). Compared with patients aged [&ge;]20 years, younger age groups had higher odds of mortality: 0-4 years (aOR = 26.74, 95% CI: 17.64-42.72), 5-9 years (aOR = 19.77, 95% CI: 13.17-31.33), 10-14 years (aOR = 8.21, 95% CI: 5.41-13.13), and 15-19 years (aOR = 2.46, 95% CI: 1.45-4.26). Prior contact with a case was associated with lower odds of mortality (aOR = 0.42, 95% CI: 0.30-0.55), whereas laboratory confirmation (aOR = 2.33, 95% CI: 1.48-3.56) and DAT receipt (aOR = 2.55, 95% CI: 2.19-2.96) were associated with higher odds. Prior vaccination was associated with lower odds of mortality among fully vaccinated (aOR = 0.52, 95% CI: 0.44-0.61) and partially vaccinated patients (aOR = 0.61, 95% CI: 0.47-0.80). Conclusions and recommendations: During the study period, diphtheria was more common among younger children, females, and the unvaccinated. Although concentrated in a few LGAs, transmission was widespread and varied seasonally. Mortality was associated with younger age, laboratory-confirmed infection, and use of diphtheria antitoxin, whereas vaccination and prior contact were protective. Reducing the burden requires sustained efforts to strengthen routine immunization, implement targeted vaccination campaigns, ensure early detection and prompt treatment, and improve contact tracing and case management.

Onchocerciasis (river blindness) is targeted for elimination through mass administration (MDA) of ivermectin (IVM) to endemic populations. In areas where loiasis, caused by the blood-borne filarial parasite Loa loa, is co-endemic, IVM MDA faced significant challenges because individuals harboring more than 30,000 L. loa microfilaria (mf)/mL of blood are at high risk of developing serious adverse events (SAEs) that can sometimes be fatal. An alternative strategy was developed for safe IVM distribution: the so-called 'Test and Not Treat' (TaNT), which identifies and excludes individuals with high mf density from IVM MDA and treats only those with minimal risk. TaNT requires a point-of-care diagnostic device to rapidly quantify L. loa parasites in field conditions. The NTDscope is a handheld device which captures bright-field videos of whole blood in capillaries. An onboard algorithm detects and counts the live microfilaria of L. loa via movement of red blood cells. This paper describes (i) a new detection algorithm; and (ii) a May 2025 field trial in Cameroon using the NTDscope with new algorithm (550 patients). Results for the TaNT use case (i.e. flagging cases with L. loa mf densities > 30,000 mf/mL): 94% to 97% sensitivity, and 94% to 97% specificity. The results indicate that the NTDscope and new algorithm provide a greater margin of safety than the predecessor device, and can potentially offer rapid, effective field detection of high mf infections to enable scalability of the TaNT strategy.

West New Britain province (WNBP), Papua New Guinea, is the first to combine ivermectin, diethylcarbamazine, albendazole (IDA), and azithromycin for mass drug administration (MDA). We describe the impact of four-drug MDA on lymphatic filariasis (LF), scabies, and yaws through active and passive surveillance. At baseline, 43 villages were surveyed following selection using model-based geostatistics. Repeat surveys were conducted in 10 high burden villages, one year after MDA. Circulating filarial antigen (CFA) and microfilaria (Mf) microscopy detected LF infections; skin examinations identified yaws and scabies. Electronic data from 27 health centers (HCs) compared monthly attendances in the six months before/after MDA. Pre-MDA, 151/3,552 (4.3%) participants tested CFA-positive, with 49 (1.4%) Mf-positive. Scabies was identified in 489/3,552 (13.8%) and yaws-like lesions in 130/3,552 (3.6%). In the 10 villages surveyed pre- and post-MDA, CFA positivity decreased by 49% (RR 0.51; CI 0.38, 0.70; p<0.0001; 11.5% to 5.9%), Mf prevalence 85% (RR 0.15; CI 0.07, 0.30; p<0.001; 4.7% to 0.9%), scabies 78% (RR 0.22; CI 0.14 - 0.33; p<0.0001; 11.1% to 2.4%) and yaws 31% (RR 0.69; CI 0.41 - 1.14; p=0.15; 3.8% to 2.5%). Mean (SEM) monthly HC attendances for yaws-like lesions decreased from 27.4 {+/-} 0.9 to 15.5 {+/-} 1.6 (p<0.0001) and for other skin diseases from 95.6 {+/-} 3.4 to 72.9 {+/-} 7.7 (p<0.0001), with no significant change in total non-skin disease attendances (728.8 {+/-} 30.9 to 796.8 {+/-} 44.4, p=0.178). MDA with IDA and azithromycin reduced LF and other skin infections burden in WNBP, demonstrating the effectiveness of four-drug MDA and the potential for using active and passive surveillance to monitor impact.

Background Schistosomiasis is a parasitic disease caused by flatworms known as schistosomes. The infection cycle starts when people shed eggs through the stool or the urine. Larva infects freshwater snails to later infect humans through the skin during water based activities. Schistosomiasis is commonly associated with rural areas. In this study, we wanted to see if the schistosomiasis distribution is different in rural and urban areas, along with potential risk factors associated with schistosomiasis distribution. Methodology Fresh urine samples were collected from 1,699 school-aged children (5 - 15 years old) in urban and rural sites in the Kimpese health district. Prevalence of haematobium and mansoni schistosomiasis was determined using, respectively, the urine sedimentation and the Point-of-Care Circulating Cathodic Antigen test with a quantitative estimate of infection intensity obtained with an RDT-Reader. Collected risk factors were tested for association with schistosomiasis infection and its intensity. Results The overall prevalence of schistosomiasis found in urban and rural areas was 75% and 82% respectively, with higher prevalence of S. mansoni in rural schools, and higher S. haematobium prevalence in urban schools. The difference in total prevalence between schools in urban and rural areas was significant, X2 (1, N = 1699) = 13.03, p = .0003. S. mansoni intensity of infection was also higher in rural children (mean = 162 mV) compared to those in urban areas (mean = 76 mV) (p < 2e-16). Male gender, washing dishes in the river, and swimming were associated with schistosomiasis in urban areas. Age, Springs, and rivers were significant factors in rural sites. Age, river, and washing dishes in the river were factors associated with the intensity of infection. Conclusion Our results showed very high prevalence in both rural and urban areas, which implies that control programs should consider them with the same interest and also revise control strategies.

Between 2017 and 2024, routine diagnostics surveillance in Guinea detected several confirmed viral hemorrhagic fever (VHF) cases among febrile patients. To assess exposure to Lassa virus and other viral pathogens, we conducted a retrospective cross-sectional seroprevalence study in Forest Guinea (Gueckedou and N'Zerekore). Lassa virus seroprevalence was 56.0% in the Gueckedou study group and 29.8% in the N'Zerekore study group. Seropositivity increased with age in both study groups, suggesting cumulative exposure. Samples from Gueckedou laboratory were also tested for other pathogens, and antibodies against Marburg virus (5.8%), Zika virus (5.4%) and Crimean-Congo haemorrhagic fever virus (1.2%) were detected.

Background: Benznidazole (BNZ) and nifurtimox (NFX) remain the only approved treatments for Trypanosoma cruzi infection, but both are associated with frequent adverse drug reactions (ADRs), long treatment duration, and limited accessibility, resulting in poor treatment adherence and premature discontinuation. Recent clinical trials have evaluated shorter and lower-dose regimens; however, the minimum level of efficacy considered acceptable by healthcare providers - in the context of improved safety and greater accessibility - has not been systematically investigated. This study aimed to identify prescriber-defined efficacy thresholds and the factors influencing prescribing preferences for new antiparasitic regimens for Chagas disease. Methods: We conducted an international, cross-sectional, web-based survey between June and August 2024 among healthcare providers, researchers, and public health practitioners with experience in Chagas disease from endemic and non-endemic countries. The survey assessed satisfaction with current antiparasitic drugs, perceived treatment disadvantages, and the willingness of practitioners to prescribe hypothetical new regimens with varying efficacy levels and additional clinical attributes. Results: Thirty of 50 invited participants completed the survey (60% response rate); most were physicians or nurses (57%), and 76% had more than six years of experience managing Chagas disease. An efficacy threshold of 70% or above was associated with substantially higher prescribing willingness: 46.7% of respondents reported being likely or very likely to prescribe a regimen with 70-79% efficacy, compared with 20.0% for 60-69% and 6.7% for 50-59%. Willingness to prescribe regimens with moderate efficacy (60-69%) was increased when regimens offered prevention of mother-to-child transmission, reduced ADR frequency and severity, or the possibility of second-line use. Improved accessibility was an additional determinant for regimen in the lowest efficacy range. Respondents identified ADRs, long treatment duration, and limited drug availability as the main disadvantages of current therapies. Conclusions: This study provides preliminary, provider-level evidence that prescriber acceptance of new antiparasitic regimens for T. cruzi infection is shaped by the overall benefit-risk profile, not efficacy alone. A 70% efficacy threshold emerged as a critical inflection point for prescribing willingness, while prevention of mother-to-child transmission, improved tolerability, and greater accessibility were identified as key factors that could support the adoption of regimens with moderate efficacy. These findings may inform the design of future clinical trials and the development of treatment strategies aligned with real-world prescribing priorities.