International journal for parasitology最新文献

Understanding the red blood cell (RBC) invasion mechanism by Plasmodium falciparum, the causative agent of human malaria, is critical for developing blood-stage vaccines. Most research on the roles of parasite molecules during invasion into the RBC has focused on the pre-invasion and invasion phases, particularly on merozoite proteins in these early steps. Consequently, well-established blood-stage vaccine candidates, such as MSP1, AMA1, EBA175, Rh5, CyRPA, and Ripr, have been discovered by research targeting the early invasion phases. Recently, we identified that Liver Stage Antigen 3 (LSA3) is a merozoite dense granule protein and a novel blood-stage vaccine candidate, given that antigen-specific antibodies inhibit parasite growth by 24%. However, the precise role of LSA3 in RBC invasion remains unclear. In this study, we investigated the function of LSA3 during merozoite invasion of RBCs. In the late-invasion phase, LSA3 localized to the posterior end of invading wild-type merozoites accessible to anti-LSA3 antibodies in the culture medium. In vitro cultured lsa3 knockout parasites (ΔLSA3) exhibited slowed parasite growth. Time-lapse imaging revealed that knockout of lsa3 resulted in a 65% reduction in normal invasion completion relative to the wild-type. Furthermore, ΔLSA3 parasites displayed a high frequency of accolé-form: aberrant morphology, with a protruding convex-shaped ring-stage just beneath the RBC membrane, following successful internalization into RBCs. This study provides the first evidence that a merozoite dense granule protein potentially plays an important role in the late-invasion phase of the P. falciparum erythrocytic cycle.

Emerging benzimidazole resistance in canine hookworms poses a growing concern for veterinary and public health. Molecular diagnostics targeting β-tubulin gene mutations are essential for resistance surveillance but traditionally rely on refrigerated faecal samples. This study evaluates dimethyl sulfoxide, EDTA, and saturated NaCl (DESS) as a room-temperature preservation medium for canine faeces. Using ITS-2 rDNA and isotype-1 β-tubulin gene (tubb-1) amplicon metabarcoding, we compared DNA integrity and diagnostic performance of DESS-preserved samples (4, 28, and 106 days) to refrigerated controls. No significant differences in PCR amplification or sequencing outcomes were observed. DESS enabled reliable detection of hookworm species and resistance-associated SNPs, including F167Y in tubb-1, with mutation frequencies consistent across treatments. Therefore, DESS can preserve samples from remote settings without cold chain logistics. Our findings validate DESS as a robust alternative for sample collection for molecular parasitology, facilitating expanded surveillance of anthelmintic resistance in field conditions.

Gregarines are a notably understudied but widespread group of protists that colonise aquatic and terrestrial invertebrates. This limited understanding of gregarines and their interactions with their hosts results partly from the absence of established culturing techniques and our understanding therefore has heavily relied on field collections. This study utilised for the first time cultured Gammarus pulex populations and comparative functional response models to explore the effects of gregarine colonisation on the host's consumption of Chironomid prey. This study shows that both positive and negative G. pulex displayed a Type II functional response. There were no statistical differences in the functional response parameters between the two groups. These results suggest that, under the study conditions, gregarines may function as commensal symbionts within their G. pulex host. This is consistent with growing evidence for gregarines acting across a range of symbiotic roles within their hosts. These findings provide insight into the role of gregarines in G. pulex, an invertebrate species frequently used for field- and lab-based experiments, contributing to the evidence of the complex and varied gregarine host-symbiont interactions.

Leishmania donovani is the causative agent of visceral leishmaniasis, a tropical disease affecting millions worldwide. While proteomic studies of Leishmania species have been conducted, the organization of protein-protein interaction (PPI) networks in L. donovani remains largely unexplored. Here, we present a protein interaction network for L. donovani generated through size-exclusion chromatography coupled with mass spectrometry (SEC-MS) and computational analysis. We quantified 3468 proteins with high confidence, of which approximately 70 % are conserved across the Tritryps (Trypanosoma brucei, T. cruzi, and L. donovani). The resulting network contains 1509 nodes and 16,095 interactions, exhibiting scale-free topology and covering key cellular machineries such as the proteasome, ribosome, translation initiation complexes, and BBSome. Remarkably, most annotated Leishmania complexes remained intact within the network, highlighting its high quality. Paralogs within L. donovani frequently interacted with each other, a phenomenon observed at a higher rate than reported in different organisms. Beyond structural organization, the network also provided interaction-based evidence that functionally contextualizes previously uncharacterized or poorly annotated proteins. Complexes involved in mRNA metabolism and flagellar assembly revealed novel components supported by conserved interaction patterns, underscoring the biological utility of the network for functional inference. Our study provides the first experimentally derived, large-scale interaction network specific to L. donovani, offering critical insights into the parasite's molecular architecture. All interaction data are available through our dedicated database at https://2025.trypsnetdb.org.

Strongyles, especially non-migratory Strongylidae, are the most common equine gut parasites, and typically occur in mixed infections with 10 - 20 species per host. Current knowledge on strongyle species prevalence and within-host tropism is sparse. Herein species composition of mixed strongyle infections of 12 naturally infected untreated young horses, based on strongyle eggs extracted from faeces, cultured third stage larva and luminal worms collected from ventral and dorsal colon was examined. Species were identified using a cytochrome c oxidase I (COI) metabarcoding approach allowing differentiation of operational taxonomic units (OTU) in small strongyle species complexes. In total, 16 small strongyle and one large strongyle species were identified. Eleven small strongyles were detected in all equines, including three cryptic species: Cylicostephanus calicatus OTU II, Cylicostephanus minutus OTU II and III. Coherence of detection rate, alpha and beta diversity showed high agreeance between data obtained using DNA from faecal eggs and cultured larvae. Diversity, but not observed richness, was higher in eggs and larvae compared to luminal worms (Inverse Simpson index, Shannon index, all P < 0.05). Bray-Curtis and Jaccard dissimilarity showed overlapping beta diversity clusters for eggs and larva, while ventral and dorsal colon samples clustered separately and differed significantly according to PERMANOVA (P < 0.001). Five small strongyle species showed significantly higher occurrence in the ventral than dorsal colon, including cryptic species Cylicostephanus calicatus OTU II. This study provides novel prevalence data for five cryptic species, documents species tropism within intestinal compartments and demonstrates high strongyle species composition agreement between faecal eggs and cultured larvae.

Equines are parasitized by complex communities of Strongylidae (Nematoda) comprising multi-species infections. Currently, Cyathostominae are most prevalent, while Strongylus species are only rarely detected. Since eggs and, in most cases, infective larvae cannot be differentiated to species level, except for Strongylus spp., species-specific knowledge of the pathology, epidemiology and ecology of these parasitic nematodes is limited. Reference sequence data for several cyathostomin species are limited or missing. Deep amplicon sequencing of internal transcribed spacer 2 (ITS-2) regions of nematodes has been used in equines previously, although barcoding studies demonstrated a better species resolution for the cytochrome c oxidase subunit I (COI) region. The present study introduces a nemabiome method based on sequencing of COI fragments. This method was applied to compare third stage larvae, representing strongyle communities, derived from regularly treated (RT) and never treated (NT) equine populations from Brazil, France (only RT), Germany, Ukraine, the UK, and the USA. Samples were predominantly from horses, but some were obtained from Przewalski's horses (Ukraine), donkeys (Germany, Ukraine) and kulans (Ukraine). Most sequence reads (87.7 %) were identified to species level, but unclassified reads occurred more frequently in donkeys and kulans than horses. No obvious difference in species diversity and richness was observed between RT and NT equines. However, there were significant differences in species composition between the RT and NT groups. Strongylus spp. were more common in NT groups but also showed unexpectedly high abundances in RT horses. Cylicocyclus nassatus, Cylicostephanus longibursatus, and Cyathostomum catinatum were more abundant in RT groups, suggesting that strongyle communities in domestic equines may have been shaped by anthelmintic treatments during last decades. The decreased classification success for reads from non-caballine equines suggests that there are more strongyle species specific for this rarely-investigated group which requires additional efforts to improve the sequence database, particularly for these hosts.

Cryptosporidiosis, a zoonotic disease caused by Cryptosporidium, is a significant threat to both livestock and human health. In this study, we systematically reviewed the prevalence of Cryptosporidium infection in bovines and ovines in China. We conducted a comprehensive search of six databases, including PubMed, Web of Science, ScienceDirect, CNKI, Wanfang, and VIP, covering studies published up to May 15, 2025. A total of 276 studies from 31 provinces were included in the meta-analysis. The overall pooled prevalence of Cryptosporidium infection was 17 % (95 % CI: 15 %-19 %) in bovines and 12 % (95 % CI: 8 %-15 %) in ovines. The most prevalent species were C. parvum (26.87 %; 95 % CI: 17.69 %-37.14 %) in bovines and C. xiaoi (26.80 %; 95 % CI: 11.81 %-45.21 %) in ovines, with dairy cattle and goats identified as the highest-risk hosts. Significant risk factors included region, age, host species, presence of diarrhoea, and sampling year. Higher infection rates were observed in Northwestern China, in younger ruminants (<6 months for bovines and <3 months for ovines), in free-ranging ruminants, and in those with diarrhoea. Prevalence was also higher in studies conducted before 2004. These findings provide important epidemiological insights and highlight the need for targeted control strategies that address key risk factors in the Chinese ruminant industry, and underscore the importance of a One Health approach that integrates animal, human, and environmental health.