International Journal for Parasitology

The nuclear, internal transcribed spacer (ITS) and mitochondrial cox1 markers are widely used to differentiate Schistosoma haematobium from its livestock counterparts, S. bovis and S. curassoni. Schistosoma isolated from humans that have ITS and cox1 markers from livestock schistosomes are typically inferred as zoonotic infections, those with mixed species, heterozygous ITS are classified as F1s or recent hybrids, while those with discordant ITS and cox1 markers are considered to reflect older hybridization events. We evaluated the reliability of this classification scheme by genotyping ITS and cox1 from 132 parasites isolated from human urine, and from 37 adult schistosomes collected from cattle at 14 Nigerian locations. We also genome sequenced each sample to empirically determine livestock schistosome ancestry. ITS/cox1 genotyping suggested extensive recent hybridization and zoonotic infection. Among parasites from humans, 10.1% carried both S. curassoni and S. haematobium ITS, consistent with F1 or early generation hybrids, 21% had livestock schistosome markers at both cox1 and ITS suggesting zoonotic infection, while 13.7% carried S. bovis cox1 alongside mixed S. curassoni and S. haematobium ITS, suggesting more complex ancestry. Genome sequencing revealed a very different picture. All parasites from humans formed a tight cluster regardless of ITS or cox1 genotype, while all worms from cattle were well differentiated. We found no schistosomes containing 50% livestock parasite ancestry consistent with F1s. Instead, we observed regionally varying levels of S. bovis introgression, with modest levels in southern Nigeria (mean = 4.9%) and low levels in northern Nigeria (mean = 0.06%). These results demonstrate that: (i) two-locus genotyping is uninformative for detecting zoonotic infection or recent hybridization between S. haematobium and livestock schistosomes and (ii) previous data generated using this approach requires reinterpretation. These findings reveal the limitations of widely-used approaches for documenting zoonotic infection and hybridization between S. haematobium and livestock schistosome species.

The liver fluke, Fasciola hepatica, is a major parasitic threat to ruminant health and productivity worldwide, with important implications for food security, animal welfare, and zoonotic risk. This study developed and validated a multiplex deep amplicon sequencing assay targeting the mitochondrial NADH dehydrogenase 1 (mt-ND1) and cytochrome c oxidase subunit 1 (mt-COX1) loci for high-throughput genotyping of F. hepatica. DNA was extracted from eggs sedimented from sheep and cattle faeces (n = 78) received from farms and from adult worm pools (n = 12) isolated at abattoirs from diverse regions across the UK. Following high-throughput sequencing, bioinformatics analysis was performed to demultiplex Illumina sequence reads and extract amplicon sequence variants (ASVs). A total of 11 ASVs were identified at each locus (mt-ND1: 264-279 bp; mt-COX1: 312-319 bp), with two or three predominant ASVs per locus, along with rare variants. Network and PCA analyses revealed two distinct clusters at the mt-ND1 locus: one primarily associated with sheep and another shared between sheep and cattle. In contrast, mt-COX1 sequence reads formed a single dominant cluster. Population analyses revealed extensive ASV sharing across regions, indicating high gene flow, likely facilitated by livestock movement and parasite adaptation.

Wildlife rehabilitation plays a central role in the conservation of threatened primates, yet parasite dynamics during captivity are rarely reported, particularly in relation to release readiness. We investigated gastrointestinal helminth infection patterns in rehabilitating Javan slow lorises (Nycticebus javanicus), a Critically Endangered species heavily impacted by the illegal wildlife trade. Using repeated fecal sampling (147 samples from 19 adults) and Bayesian mixed-effects models, we examined parasite richness, Shannon diversity, infection probability, and egg-shedding intensity in relation to release readiness status, sex, housing condition, and time since anthelmintic treatment. Four nematode taxa identifiable through egg morphology were detected: Strongyloides spp., strongylids, oxyurids, and Trichuris spp.. Parasite richness and Shannon diversity showed no credible associations with release readiness or other host and management variables. In contrast, infection probability for Strongyloides spp. and strongylids increased with time since deworming, and Strongyloides egg counts exhibited a similar temporal pattern, consistent with post-treatment reinfection dynamics. Release readiness did not predict detection probability or parasite intensity for any parasite group, despite marked differences in captivity duration and health history between individuals deemed ready for release or not. These findings indicate that gastrointestinal helminth dynamics in rehabilitating slow lorises are driven primarily by treatment-related temporal processes and individual-level heterogeneity rather than coarse host classification. They also highlight the need for longitudinal parasite monitoring and for future work evaluating how infection dynamics, management interventions, and host health relate to rehabilitation and translocation outcomes..

Background: Female genital schistosomiasis (FGS) is a neglected gynaecological manifestation of Schistosoma haematobium (S. haematobium) infection, resulting from the deposition of parasite eggs in the female genital tract. Although urogenital schistosomiasis is highly prevalent in parts of coastal Kenya, including Kilifi County, the burden of FGS among women of reproductive age remains poorly characterised. Routine diagnosis of S. haematobium infection relies largely on urine microscopy, which may underestimate genital involvement. This study aimed to assess the prevalence, diagnostic concordance, and risk factors for FGS among women of reproductive age in Kilifi County, Kenya. Methodology: In this cross-sectional study, 320 randomly selected women aged 15-50 years were recruited from rural Kilifi County; 261 provided complete data for analysis. A structured questionnaire was administered to collect sociodemographic and behavioural information. Urinary schistosomiasis was assessed using triplicate urine microscopy over three consecutive days, and FGS was evaluated using real-time polymerase chain reaction (PCR) targeting the S. haematobium Dra1 gene sequence on self-collected high vaginal swabs. Results: Overall, the prevalence of PCR-confirmed FGS was 36.0% (94/261), while urinary egg excretion was detected in 13.0% (34/261) of participants. Concordance between urine microscopy and genital PCR was 70.9%. Notably, 72% of women with PCR-confirmed FGS had no detectable parasite eggs in their urine. In bivariate analyses, factors such as urinary infection severity, water contact behaviours, haematuria, dysuria, age group, place of residence, and prior history of schistosomiasis were found to be associated with female genital schistosomiasis (FGS). However, in the multivariable logistic regression, only sub-location and urinary infection severity remained independently associated with the infection. Additionally, PCR cycle threshold (Ct) values showed a non-linear relationship with mean urinary egg counts, indicating that the detection of genital parasite DNA does not directly correspond to the urinary egg burden. Conclusion: FGS prevalence among women in Kilifi County was substantially higher than indicated by urine microscopy alone. The majority of women with genital schistosomiasis did not exhibit detectable urinary egg excretion, highlighting the limitations of routine parasitological screening for identifying genital disease. These findings underscore the need to incorporate genital sampling and molecular diagnostics into schistosomiasis control strategies targeting women of reproductive age in endemic settings.

BackgroundIntestinal helminth infections trigger complex host responses, determining parasite survival and tissue homeostasis. Primary Echinostoma caproni infection disrupts epithelial metabolism, differentiation, and repair in an IL-25-deficient environment, as shown in a previous study by our research group; however, the adaptive mechanisms during homologous superimposed infections remain unclear. Methodology/Principal findingsMale ICR mice were assigned to control, primary infection, and homologous superimposed infection groups, and ileal epithelial cells were isolated for proteomic profiling using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with data-dependent acquisition (DDA) and sequential window acquisition of all theoretical mass spectra (SWATH). Differential protein expression was analyzed with Elastic Net regression, partial least squares discriminant analysis, and fold-change ranking, while functional enrichment and protein-protein interaction networks were explored using gene set enrichment analysis (GSEA) and STRING. Notably, homologous superimposed infection revealed proteomic signatures associated with lysosomal and peroxisomal lipid metabolism, PPAR pathway activation, cytoskeletal reorganization, epithelial barrier reinforcement, a specialized antimicrobial peptide repertoire, and interactions between IgE receptor-associated proteins, consistent with a restoration of intestinal homeostasis influenced by IL-25. ConclusionsHost adaptation to repeated E. caproni exposure involves coordinated metabolic, signaling, and tissue repair responses that partially restore intestinal homeostasis, with IL-25 emerging as a central regulator linking metabolic reprogramming, epithelial integrity, and anti-helminth immunity, thereby providing a proteomic framework for understanding how repeated helminth exposure drives partial resistance through integrated epithelial and immunometabolic adaptations. Author summaryWe investigated how repeated intestinal worm infections affect the cells lining the small intestine in mice. Infections with intestinal trematodes can disrupt the normal balance of the gut, leading to tissue damage and altered metabolism. Using a proteomics approach, we measured changes in thousands of proteins in intestinal epithelial cells during a first infection and after a second, repeated infection. We found that the first infection caused stress in the cells, impaired oxygen use, and reduced the activity of pathways that normally help repair tissue. In contrast, the repeated infection triggered a coordinated response that restored many cellular functions. Cells increased protein activity related to fat metabolism, tissue structure, barrier integrity, and antimicrobial defense. We also observed evidence that the immune signaling molecule interleukin-25 plays a central role in coordinating these protective and repair processes. These results suggest that the gut epithelium can adapt to repeated infections by reorganizing its metabolic and structural functions, which may help limit tissue damage and promote partial resistance to parasites. Our study provides a detailed map of the molecular changes that underlie this adaptation, improving our understanding of how the intestinal lining responds to repeated worm infections.

Close to 50% of all bird species are reservoirs of potentially pathogenic fungi, including those listed as priority by the World Health Organization. In Malawi, data on diversity, pathogenic potential, and ecological avian sources of medically important yeast are scarce. A cross-sectional study using a descriptive approach was conducted in Blantyre, Southern Malawi, to characterise medically important yeasts recovered from environments contaminated with excreta/guano from synanthropic pigeons. A total of 20 samples were collected from 4 peri-urban areas, which yielded 71 yeast isolates. To assess the pathogenic potential of the environmental isolates, we compared their phenotypic virulence traits with those of 21 clinical yeast isolates collected from referral hospital laboratories. Pichia kudriavzevii (39%) and Candida orthopsilosis (30%) were the commonly isolated species in the pigeon-guano-contaminated environments. Candida parapsilosis sensu stricto (29%) and Candida albicans (24%) constituted most of the clinical yeast isolates. Half of the species isolated in the pigeon-guano-contaminated environments were also identified among the clinical isolates. A majority of the environmental isolates showed virulence traits similar to or stronger than clinical isolates. The findings underscore the critical need for integrated surveillance under the One Health framework, especially in bird-inhabited spaces close to human settlements.

AimTo resolve the topological branching patterns, the timing of demographic events, and the effective population size changes associated with major demographic events. LocationMidwestern (eastern North Central) and Northeastern USA TaxonBlacklegged tick, Ixodes scapularis (Say, 1821) MethodsUsing three independent genomic datasets, single-nucleotide variants were analyzed for demographic inference. Maximum likelihood topologies and prior ecological knowledge were used to generate nested demographic hypotheses. The best-fit scenario and the associated demographic parameter estimates were determined using approximate Bayesian computation under a random forest statistical model. The topologies and parameters supported in the three independent datasets were compared to generate insights about the demographic history of blacklegged ticks in the region. ResultsThe emergence of extant northern populations of blacklegged ticks began between 10-15 k.y.a. (thousand years ago), with independent population splits from the common ancestor during the Early-Mid-Holocene, and never more recent than 4 k.y.a. All populations sustained moderately large population sizes without bottlenecks, with Michigan as the exception. Michigan appears to have an uncertain placement that depends on sampling, reflecting its admixed origin. Main conclusionsThere are multiple populations of northern blacklegged ticks that have persisted independently as deglaciated regions in the northern U.S. were recolonized following the Last Glacial Maximum (26.5 to 19 k.y.a.). The current ecological expansions across the northern U.S. are likely seeded by separate relictual populations with distinctive genomic ancestry rather than a range expansion from a single source, with important implications for vector-borne disease management.

Whipworms (Trichuris spp.) are intracellular intestinal parasites that develop within the host caecal epithelium, yet the host signals that regulate their growth and developmental progression remain poorly understood. Progress in studying these processes has been limited by the lack of physiologically relevant in vitro systems capable of supporting sustained whipworm development. Here, we established an in vitro infection system using caecal organoids (caecaloids) and evaluated their capacity to support sustained growth and morphological development of Trichuris muris larvae. To rigorously validate this system, we generated a comprehensive and up-to-date anatomical and biometrical reference dataset describing the whole-body growth and tissue-level morphogenesis of T. muris throughout its life cycle in vivo. Quantitative analysis across larval and adult stages confirmed that the trajectory of parasite growth is largely conserved across host mouse strains and provided a detailed contextualised description of the development of key anatomical structures of T. muris. Using this reference framework, we evaluated parasite growth and development in long-term T. muris-caecaloid co-cultures. Larvae invading the caecaloid epithelium remained intracellular within syncytial tunnels and exhibited sustained growth over extended culture periods. in vitro parasites developed increasing anatomical complexity, including formation of the bacillary band, stichosome, intestine, and rectum. Importantly, quantitative comparisons revealed that larvae developing within caecaloids follow growth trajectories and morphological developmental patterns closely resembling those observed in vivo. This study therefore presents the first detailed anatomical and morphometric framework for validating whipworm development in an organoid system and provides concrete evidence that the caecaloid epithelium is sufficient to trigger and sustain whipworm growth and morphogenesis, establishing caecaloids as a powerful experimental platform for investigating Trichuris infection and development.

Soil-transmitted helminths (STHs) pose significant challenges to public health in endemic areas, necessitating reliable methods for their detection. Shotgun metagenomics enables simultaneous detection of STHs and microbes in a sample without prior knowledge of what is present. However, validation of shotgun metagenomics with known infection intensity or across different sequencing platforms has not been carried out for eukaryote parasites including STHs, and false positives remain a pervasive issue. We validated shotgun metagenomics as a method of STH detection in faecal samples. Using the Strongyloides ratti laboratory model of a STH infection we investigated how analytical methods (nucleotide-nucleotide matching, nucleotide-protein matching, marker gene detection, mitochondrial mapping), infection intensity and sequencing technology (short-read vs. long-read) affects sensitivity and specificity of detection. S. ratti was accurately detected at a standard laboratory dose, but low intensity infections were more difficult to detect. Only mitochondrial sequence mapping was 100% accurate at identifying S. ratti with no false positives. Overall, short-read outperformed long-read sequencing methods. We applied the same analytical methods to human faecal samples with confirmed infections for at least one of four STHs. Mitochondrial sequence mapping was also the most effective method for detecting STHs in human faecal samples, detecting 100% of Necator americanus and 92% of Ascaris spp. infections, but could not reliably detect STHs where DNA levels are expected to be low or variable. In conclusion, mitochondrial mapping was the most effective method of detection for sensitivity and specificity in both the laboratory system and human faecal samples. Our findings indicate that shotgun metagenomics should be approached cautiously using validated methods, particularly when infection intensity or DNA levels are expected to be low. Author SummarySoil-transmitted helminths (STH) such as the parasite Strongyloides, are important gastrointestinal parasites of humans and livestock. Accurate methods of detection for diagnostics and monitoring are important to implement suitable control and treatment strategies. Here we validate a shotgun metagenomics approach, where all DNA in a sample is sequenced, for detecting STH in faecal samples using a Strongyloides laboratory model for infection. Strongyloides was reliability detected in faecal samples at higher infection levels, but mitochondrial genome mapping of the sequences was the only analytical method that reliably detected Strongyloides at lower infections levels. These results were reflected in stool samples from humans infected with STH, where mitochondrial mapping was also the most reliable method. However, species that were associated with low levels of parasite material or DNA in the faeces including Strongyloides stercoralis, were more difficult to detect. We compared two sequencing methods: short-read Illumina and long-read Oxford Nanopore Technologies, but short-read outperformed long-read shotgun metagenomics. Contamination of bacteria sequences in parasite genome assemblies was problematic for analysis and contributed to false positive results. Future work should focus on specific targeting of eukaryote DNA either at the laboratory or bioinformatic stage to improve STH detection further.

Parasite infections in wildlife vary across time and space due to interactions among host biology, ecological processes, and climatic variability. Under ongoing climate change, understanding how temperature, precipitation, or humidity influences parasite dynamics is important for predicting shifts in infection patterns and host-parasite interactions. Here, we examine how variation in climatic conditions is associated with helminth infections in a free-living rodent, the bank vole (Myodes glareolus), across 17 years and multiple spatial scales. Using zero-inflated generalised linear models, we quantified the effects of climatic variables on individual parasite burden. Climatic conditions (temperature and humidity or precipitation) affected helminth infections across all analysed scales, though the strength and direction of these effects differed among parasite species and between temporal and spatial scales. In the temporal dataset, parasite load was associated with seasonal variation in weather conditions, whereas in the spatial datasets, infection levels were linked to yearly average climatic variables. The differences reflect species-specific parasites life histories and transmission strategies. Our findings highlight the importance of analysing individual parasite species rather than overall parasite load or aggregated infection indices when assessing the impacts of climatic variation on host-parasite dynamics.

Helminthiases remain a major global health burden, and limitations of current anthelmintic therapies highlight the need for new pharmacological targets. In this study, we examined the effects of ion-channel and cytoskeletal modulators on bovine lung protoscoleces (PSCs) of Echinococcus granulosus sensu lato. Compounds acting on ion channels (praziquantel, amiloride, and amlodipine) and cytoskeletal components (albendazole and cytochalasin D) were evaluated using a semi-automated motility assay, methylene blue exclusion to assess viability, and scanning electron microscopy (SEM) to characterize structural damage. All compounds produced concentration-dependent reductions in PSCs motility. Amlodipine was the most potent inhibitor of motility, whereas praziquantel and cytochalasin D produced pronounced tegumental alterations and strong correlations between motility impairment and parasite death. In contrast, amiloride markedly reduced motility with comparatively minor effects on viability, indicating a primarily paralytic effect. Cytoskeletal disruption induced severe structural damage and parallel declines in motility and viability. SEM analysis revealed extensive tegumental collapse, loss of glycocalyx, and microtrichial damage in PSCs exposed to cytoskeletal and calcium-modulating agents. These findings highlight cytoskeletal organization and calcium-dependent ion fluxes as key physiological vulnerabilities in E. granulosus. Comparative analysis of these pharmacological targets provides mechanistic insight into how disruptions in cytoskeletal dynamics and cation homeostasis compromise parasite motility and survival.

Anthelmintic drug resistance is a concern for the sustained control of gastrointestinal nematodes (GINs) in ruminant livestock globally. Evolutionary-epidemiological modelling, which considers both parasite dynamics and resistance dynamics in response to interventions, can be useful in determining which anthelmintic resistance management (ARM) strategies may be effective without compromising parasite control. We address two key questions in ARM. First, how to improve the measurement of AR in populations. Second, identifying effective ARM strategies to slow the spread of AR while maintaining effective parasite control. We developed a simulation framework which tracks the weather-dependent epidemiology of GINs and AR evolution, providing a highly flexible methodology to evaluate multiple ARM strategy options in a single modelling framework, allowing for novel insights due to direct comparisons between strategies. Simulations to refine our understanding of anthelmintic resistance management evaluated the impact of key areas of uncertainty, including transmission intensity, resistance intensity, resistance frequency, drug decay and linking faecal egg count reduction tests (FECRT) to resistance allele frequency. Large-scale simulations present a methodologically thorough evaluation of how treatment choices simultaneously impact epidemiological and evolutionary outcomes. Phenotypic classifications of resistance status using FECRT failed to capture fine scale changes in resistance allele frequency. The pharmacokinetics of drug decay strongly influenced ARM outcomes, and trade-offs between ARM and effective parasite control depends on genetic factors underpinning resistance. Combination therapies appear to be the most effective resistance management strategy evaluated. Our findings suggest practical implementations to manage anthelmintic resistance must simultaneously consider parasite transmission, pharmacology and parasite genetics to be robust and sustainable. We provide a rigorous simulation framework to enable such discussions allowing for a refinement into our understanding of parasite control in the presence of resistance evolution.

African Animal Trypanosomosis (AAT) is a disease affecting domestic animals, in particular cattle, in sub-Saharan Africa, resulting in billion-dollar losses annually. New drugs to combat and control AAT are urgently required, yet few treatment candidates are currently on the horizon. This can be attributed, in part, to the relative challenges associated with culturing the clinically relevant parasite species in a laboratory environment. Particularly, effective culture of bloodstream form Trypanosoma congolense, the trypanosome species responsible for a large proportion of AAT disease in cattle, requires the use of goat serum, whilst T. brucei is typically cultured in FBS-supplemented culture. This constrains in vitro studies on biology, especially comparative analyses between AAT-causing species. The differing serum supplementation requirements of these two trypanosome species point to metabolic distinctions, which may be important considerations in developing experimental systems to enable the identification and design of novel, pan-species therapies. In this study, untargeted LC-MS lipidomics analyses were conducted to determine the relative lipidomic profiles of T. congolense and T. brucei bloodstream form parasites. Employing a new media formulation that permits effective in vitro culture of both species, it was possible to establish that their global lipidomic profiles are distinct. Notably, T. congolense exhibits a relatively low abundance of ether phospholipids compared to T. brucei, whilst also possessing an enrichment of long-chain polyunsaturated fatty acids (PUFAs). These observations indicate that there are significant differences in the ways these parasites synthesise and remodel their lipid complement, highlighting an evolutionary divergence between the species that likely carries implications for host-pathogen interactions as well as trypanosome membrane biology. Furthermore, this study demonstrates that fine-tuning fatty acid supplementation may aid in optimising a universal medium suited for multiple species of AAT parasites. SummaryMultiple species of protozoan parasites can cause African Animal Trypanosomosis (AAT) in livestock and other animals. However, AAT research has largely centred on a single species, Trypanosoma brucei, partially due to the comparative difficulties in sustaining the other economically important parasite species - Trypanosoma congolense and Trypanosoma vivax - in laboratory culture. In this work, we aimed to determine whether distinctions in use of lipids between T. brucei and T. congolense explains their differing in vitro culture requirements. Using a newly designed media formulation, it was possible to culture mammalian-infective forms of both parasite species under identical conditions, enabling direct comparison of their lipidome - a complete inventory of the different fats and lipids the cells contain. We demonstrate that the T. congolense lipidome significantly differs from that of T. brucei, and that T. congolense shows a preference for longer, more unsaturated lipids. These differences are likely to underlie species-specific differences observed during host infections. Furthermore, our work demonstrates that understanding the lipid biology of protozoan parasites aids in optimisation of laboratory culturing conditions, thereby facilitating further research into these understudied pathogens, including the development of new therapies.

Haemosporida is a diverse order of vector-borne apicomplexan parasites infecting terrestrial vertebrates worldwide, including humans, but the evolutionary relationships among its genera remain unresolved. The phylogenetic placement of two bat-restricted genera, Nycteria and Polychromophilus, both of which lack erythrocytic schizogony, has varied across studies depending on taxon sampling and marker choice. To address this problem, an expanded dataset of near-complete mitochondrial (mtDNA) genomes together with nine nuclear loci were analyzed. Phylogenetic analyses of mtDNA recovered Nycteria and Polychromophilus as a strongly supported monophyletic clade. In contrast, analyses based only on the three mitochondrial coding genes (CDS) or a reduced nuclear dataset failed to recover their monophyly and showed low support and extensive topological conflict at deeper nodes. These results indicate that near-complete mitochondrial genomes recover phylogenetic signal that is not captured by reduced mitochondrial coding sequences or partial nuclear datasets. Molecular dating analyses further showed that divergence estimates for a putative Nycteria-Polychromophilus clade are compatible with the proposed times for bats diversification, and consistent with the broader haemosporidian timescale. When the Nycteria-Polychromophilus clade was incorporated as a calibration prior, divergence-time estimates became more precise without altering the overall evolutionary timeframe. Substantial mitochondrial gene-order rearrangements in a distinct Nycteria lineage were confirmed, highlighting structural divergence within this bat-associated group. In addition, heterogeneity in rates across mtDNA haemosporidian lineages was observed. Together, these findings support the existence of a distinct bat-associated clade whose deeper placement and evolutionary significance should be tested with broader phylogenomic sampling. Author SummaryMalaria parasites belong to a diverse group of organisms that infect many kinds of vertebrates, including birds, reptiles, and mammals (such as humans). Understanding how these parasites are related to each other is important for explaining how key biological traits have evolved. However, the relationships among major groups of haemosporidian parasites, including malaria parasites, remain unclear, particularly for those infecting bats. In this study, we focused on two groups of bat parasites, Nycteria and Polychromophilus, which share unusual biological features. The inferred evolutionary relationships of these two genera to other haemosporidians have been inconsistent across previous studies. By analyzing near-complete mitochondrial genomes, we found strong evidence that these two groups descended from a common evolutionary ancestor. In contrast, smaller datasets including nuclear genes failed to recover this relationship and produced conflicting results, suggesting that they lack sufficient information to resolve deep evolutionary relationships. We also found that this bat-associated lineage likely originated around the same time as early bats. In addition, we identified structural changes in the mitochondrial genome of one lineage, highlighting its evolutionary distinctiveness. Together, our results suggest that bats host a unique group of malaria parasites and demonstrate that more complete genetic data are essential for resolving their evolutionary history.

Cystic echinococcosis (CE), caused by the larval stage of Echinococcus granulosus, remains a significant public health and veterinary problem in endemic regions. Although chemotherapy and control programs exist, the development of complementary immunotherapeutic tools is increasingly needed. This study evaluated the generation and functional activity of hyperimmune serum (HIS) produced in three adult male castrated llamas (Lama glama) immunized with antigenic material derived from protoscoleces (PSCs) of the parasite. Sera collected after each of the first six immunizations were assessed by ELISA to quantify antigen-specific IgG responses, and their biological effects were tested in vitro using viable PSCs. Motility was measured using video-assisted paired-image scoring across serial serum dilutions (1:2-1:2048), and the methylene blue exclusion assay was used to assess viability. Hyperimmune serum produced a clear, reproducible, dose-dependent inhibition of PSC motility and viability. Higher titers of early inoculations reduced motility by 70-85%, while sera from the fifth and sixth inoculations achieved complete suppression. Naive serum and PBS controls showed no inhibitory effect. ELISA titers strongly correlated with biological activity, indicating that higher humoral responses predicted functional inhibition. These findings demonstrate the feasibility of generating potent anti-Echinococcus granulosus polyclonal antibodies in camelids and support their potential application in passive immunization strategies. The study establishes a foundation for future development of llama-derived immunobiological reagents, including nanobody-based tools, for the control of cystic echinococcosis.

Background Urogenital schistosomiasis (UGS), caused by Schistosoma haematobium (S. haematobium), disproportionately affects women in sub-Saharan Africa and can lead to haematuria, anaemia, and urinary tract morbidity. Data on the prevalence in women of reproductive age remains limited in contrast to infection among school-aged children in Kenya. This study assessed the prevalence of UGS and its socioeconomic determinants among women in Kilifi County, Kenya. Methods: Urine samples (20-50 mL) were collected from each participant over three consecutive days. Day-one samples were tested for haematuria, proteinuria, nitrites, leukocytes, and pregnancy using dipsticks. On the other hand, 10 mL of urine was examined for S. haematobium eggs via urine filtration on all three days. Results: A total of 599 women aged 15-50 years were enrolled, with complete data available for 336. The mean age was 33 years; 57.7% were <35 years. Most participants were from rural Magarini Sub-county (63%) and engaged in crop farming (62.5%). Primary education was the highest level attained by 59.8% of participants. Frequent contact with stagnant water was reported by 92%. The overall prevalence of S. haematobium infection was 13.7% (95% CI: 10.2-17.8), higher in Magarini (14.9%) than in Rabai (12.0%), though not statistically significant. Younger age, primary education, and frequent water contact were associated with higher infection rates; however, after adjustment for covariates, haematuria showed the strongest independent association with infection. Women with haematuria were 25.2 times more likely to be infected (OR: 25.24, 95% CI: 7.07-82.63, p < 0.001); multivariate analysis confirmed haematuria as the sole significant predictor (OR: 20.83, 95% CI: 5.45-79.57, p < 0.001). Conclusion: UGS prevalence among women in Kilifi County is substantial, with variation between sub-counties. Haematuria demonstrated the strongest independent association with infection and may serve as a simple, non-invasive diagnostic marker. These findings underscore the pressing need for the integration of UGS screening into the reproductive health services and targeted interventions. Authors Summary UGS, caused by the parasitic worm Schistosoma haematobium, is a neglected tropical disease and remains a major public health problem in sub-Saharan Africa. Although control programmes in Kenya primarily target school-aged children, women of reproductive age are frequently exposed through daily water contact and may develop chronic urinary and reproductive health complications. However, data on the infection burden among adult women are limited. In this study, we assessed the prevalence of urogenital schistosomiasis and associated risk factors among women aged 15-50 years in Kilifi County, Kenya. Urine samples were collected over three consecutive days and examined for parasite eggs and indicators of urinary tract disease. We found that urogenital schistosomiasis affected more than one in ten women in the rural sub-counties where the study was conducted. Haematuria was strongly associated with infection and remained the most reliable predictor after accounting for other social and behavioural factors. These findings demonstrate that UGS is an under-recognised health issue among women and highlight the potential value of simple urine-based screening tools. Integrating UGS screening into existing reproductive health services could improve early detection and contribute to more inclusive disease control strategies.

Progress towards elimination of onchocerciasis transmission is evaluated using entomological and serological indicators. The latter assesses anti-Ov16 IgG4 seroprevalence in children aged <10 years. A seroprevalence of <0.1% suggests that ivermectin Mass Drug Administration (MDA) can be stopped and post-treatment surveillance initiated, according to World Health Organization (WHO) guidelines. Surveillance of populations living in close proximity to vector breeding sites and first-line villages may mask spatial transmission heterogeneity. We mapped anti-Ov16 seroprevalence within a 25-km radius around a known Simulium damnosum s.l. breeding site in Asubende, Ghana, to assess its spatial patterns and their implications for serosurveillance. A cross-sectional survey was conducted in September-November 2024 in 30 settlements. Individuals aged [&ge;]3 years were recruited through convenience sampling. The Ov16 rapid diagnostic test (RDT) using dry blood spots was used to estimate overall and site-level seroprevalence. Generalized additive models were used to assess seroprevalence trends versus distance from the breeding site. Among 2,479 participants with valid RDT results, overall seroprevalence was 10.0% (95% CI: 8.9%, 11.3%) and increased with age. Seroprevalence varied across sites (0-24.4%) and declined with increasing distance from the breeding site. Among 584 children <10 years old, seroprevalence was 1.5% (95% CI: 0.7%, 2.9%). Adjusting for RDT sensitivity and specificity, seroprevalence in this age-group was 0.7%, (95% CI: 0%, 2.4%). Seropositive children were detected up to 18 km from the breeding site, but none were identified at it. The distance-related decrease in overall seroprevalence is consistent with spatial patterns in vector abundance at Asubende and implies higher cumulative exposure near the breeding site. The small number of children tested limited inference in this WHO target age-group. Detection of seropositive children away from, but not at, the breeding site highlights limitations of surveillance focused on first-line villages and supports broader spatial sampling to strengthen evidence for stop-MDA decisions. Author summaryAfter decades of onchocerciasis control using ivermectin, many countries hope to demonstrate that they have interrupted transmission of this vector-borne parasitic disease using serological surveys. It is unclear whether exposure to infection is spatially clustered around the riverine breeding sites of the blackfly vectors and therefore whether this is where serosurveillance should focus. To address this, we collected dried blood spots from 2,480 consenting participants aged 3-96 years old from 29 communities within a 25-km radius of a known blackfly breeding site in Asubende, Ghana. A rapid diagnostic test was used to test the blood spots for antibodies to the Onchocerca volvulus parasite. We found that overall seropositivity declined with increasing distance from the breeding site, which suggests that cumulative exposure is higher near the breeding site, where vector population is also high. However, seropositivity in children (3-10-year-olds, n= 584), which is indicative of recent transmission, was spatially distributed across the study area and found up to 18 km from the breeding site. These findings are relevant to serosurveillance sampling strategies intended to detect low levels of transmission, which could miss peripheral evidence of ongoing transmission if they are focussed at breeding sites and those villages closest to them.

Plasmodium falciparum merozoites invade erythrocytes using various ligand-receptor interactions. Important ligands encoded by the eba and Rh gene families have varying expression levels in different parasite isolates, affecting their vaccine candidacy. Analyses of clinical isolates from endemic areas in Africa have indicated that most variation in these expression profiles exists within each local area, and only minor differences are seen between areas, although comparisons with non-African populations have not previously been performed. To enable this, relative transcript levels of three eba genes and five Rh genes have been analysed in new population samples, Malaysian isolates sampled from Sabah State in Borneo prior to endemic malaria elimination, and Gambian isolates, cultured under the same conditions to harvest schizonts for reverse transcription quantitative PCR assays. Significant differences between these populations were seen for three of the ligand genes, levels of eba175 being higher in Malaysia, while levels of eba181 and Rh2b were lower in Malaysia. The gene transcript profiles did not differ between single genotype and or multiple-genotype isolates. The distinctness of the Malaysian population expression profile was also supported by comparing previous data on clinical isolates from Ghana. In tests for correlation with previously determined parasite multiplication rates, eba181 transcript levels correlated positively among Malaysian isolates but not among Gambian isolates. These findings suggest that expression of three P. falciparum merozoite ligands involved in invasion may be regionally differentiated, and further analysis of Asian parasite populations would be important if vaccines based on these candidates are to be considered for future use.

Repressor-of-differentiation kinase 1 (RDK1) is one of two kinases expressed in bloodstream form Trypanosoma brucei parasites that were found to repress premature and spontaneous differentiation into the insect procyclic form. However, the effect of RDK1 RNAi was previously limited to the expression of a single surface coat protein, EP1 procyclin. Thus, there remains a significant gap in knowledge on the impact of RDK1 expression in bloodstream form T. brucei parasites. Here, we employ a systems biology approach and performed several proteomics analyses to identify RDK1 protein interactions and to determine the impact of loss of RDK1 expression on the bloodstream form proteome and phosphoproteome to uncover clues about potential mechanisms for RDK1 function. We found that RDK1 is dual localized to the cell membrane and the mitochondrial inner membrane with the kinase domain oriented towards the cytoplasm and mitochondrial inner membrane. Unexpectedly, the most enriched RDK1-proximal proteins were mitochondrial proteins. Furthermore, RDK1 depletion causes bloodstream form parasites to significantly upregulate many mitochondrial proteins and glycosomal proteins, several of which are upregulated in procyclic form parasites. Surprisingly, the mitochondrial phosphoproteome is largely unaffected by RDK1 depletion, while RDK1-dependent phosphoregulation is restricted to the cell membrane localization of RDK1. Lastly, we determined that RDK1 does not possess adenyl cyclase activity or alter intracellular cAMP levels; however, the dysregulated phosphoproteins correlate with functions in cyclic nucleotide signaling. In conclusion, RDK1 exhibits localization-specific kinase activity to regulate cyclic nucleotide signaling and mitochondrial proteomic maintenance in bloodstream form parasites. IMPORTANCETrypanosoma brucei is the unicellular parasite that causes African sleeping sickness and nagana disease in livestock across 36 sub-Saharan African countries. The parasite encounters different environmental niches as it is transmitted from an infected human to the tsetse fly vector as the fly takes a blood meal. T. brucei must sense environmental cues to initiate intracellular signaling pathways to promote effective differentiation and cellular remodeling from the mammalian bloodstream forms to the insect procyclic form. RDK1 is one of two kinases shown to repress premature differentiation to procyclic form, which would be detrimental for parasite survival in the human host. Therefore, it is essential to uncover mechanisms of RDK1 function to better understand how T. brucei maintains homeostasis in the human host and signals for effective cellular remodeling during parasite transmission.

Helminths are parasitic worms that secrete a variety of immune-regulating molecules to modulate the hosts inflammatory responses, enabling them to persist within the host over a long period of time, even decades. Their capacity to control host responses has prompted research into helminth-derived molecules as potential therapies for controlling excessive immune and inflammatory activity across a range of diseases. This systematic review with cross-study quantitative analysis aims to synthesize the published data on helminth-derived immunomodulatory peptides/polypeptides/proteins (HDIPs) with a focus on determining the extent of their disease-modifying and anti-inflammatory potential in in vivo animal models of inflammatory disease. In accordance with PRISMA 2020 guidelines, a predefined systematic search of the PubMed, Web of Science and Medline databases identified relevant studies published up to February 2026, and 65 articles were included after screening. We found that, although the HDIPs were assessed in multiple different disease models, most published studies assessed their potential in mouse models of colitis, asthma, arthritis and sepsis. Twenty species from which >65 isolated HDIPs were derived were tested in these models, with the trematode, Fasciola hepatica, and the nematode, Acanthocheilonema viteae, the most explored species. A common property of the HDIPs was the ability to significantly reduce disease severity across the in vivo animal models of inflammatory disease, underpinned by a decrease in pro-inflammatory cytokine levels and an increase in anti-inflammatory cytokine levels. Overall, this systematic review with cross-study quantitative analysis not only synthesizes the existing literature in this field but also highlights the disease-modifying and anti-inflammatory potential of HDIPs for a range of diseases in which immunoregulatory therapeutics may improve disease outcomes. It also encourages accelerated advancement of these helminth-derived molecules into first-in-human clinical trials.