International journal for parasitology最新文献

Honey bees are recognised as the primary pollinators of most agricultural crops and numerous wild plant species worldwide. However, the colony losses reported over recent decades pose a serious threat to this essential ecosystem service. The spread of pathogens has been identified as a significant factor contributing to the decline of honey bee populations. Consequently, there is a considerable interest in expanding our knowledge on the prevalence of emerging pathogens on honey bee colonies, particularly trypanosomatids and neogregarines. Herein, we conducted a spatio-temporal analysis of the prevalence of trypanosomatids (Lotmaria passim and Crithidia mellificae) and a neogregarine (Apicystis bombi) in honey bee populations across the Canary Islands sampled over a 20-year period (1998-2017). We also examined whether pathogen prevalence was associated with the introduction of foreign honey bee queens to the islands and the implementation of a conservation programme of the local Canarian black honey bee. Our results indicate that L. passim has been present in the Canary Islands since at least 1998, whereas C. mellificae was not detected. This finding represents the earliest known global record of the L. passim worldwide. Apicystis bombi was found on several islands during the study period, though at low frequency. The prevalence of L. passim did not exhibit any correlation with the introduction of foreign honey bee queens, unlike other pathogens and parasites such as Nosema ceranae and Varroa destructor. Notably, the implementation of long-standing conservation measures in La Palma was associated with a higher prevalence of L. passim compared to Gran Canaria. These results suggest that L. passim may have been present in the Canary Islands prior to the introduction of foreign honey bees in recent decades. Further analyses of historical samples from additional regions, particularly from geographically isolated areas such as islands, are necessary to untangle the spread history of L. passim in honey bee populations.

Ascaridia galli (A. galli), a parasitic roundworm that infects chickens poses an economic burden in poultry farming, as it causes ascaridiosis-a disease leading to reduced growth, lower egg production, and immunosuppression. Recently, interest has grown in the parasite's extracellular vesicles (EVs), as they modulate host immune responses and play a key role in host-pathogen interactions. This study aimed to optimize in vitro EV-production from A. galli and assess their uptake by chicken immune cells important for EV mediated host-pathogen communication. Adult worms were collected from infected chickens, sex-sorted, washed, and cultured in vitro. EVs were isolated at various time points using size exclusion chromatography and characterized. DiO-stained EVs were evaluated for uptake into chicken intestinal epithelial cells, macrophages, peripheral blood mononuclear cells and whole blood leukocytes using flow cytometry and confocal microscopy after 4 and 24 h incubation with the parasite derived vesicles. EV-uptake increased significantly from 4 h to 24 h across all tested cell types. Female-derived EVs collected after 24 h of worm culture gave rise to higher uptake than male-derived EVs. However, at the 40 h time point, male EVs gave rise to greater uptake, though overall EV internalization was reduced compared to the 24 h time point. Uptake efficiency varied depending on the EV collection time as well as the host cell type. These findings suggest that both the sex of the worm and the duration of culture influence EV uptake, with 24 h emerging as the optimal in vitro culture duration for production of A. galli derived EVs with potent biological functions. The sex-specific differences highlight potential functional diversity in EV mediated host-pathogen interactions, which need to be assessed in future studies.

Mitochondrial genomes of apicomplexan parasites exhibit remarkable structural diversity, ranging from highly reduced linear molecules to circular-mapping concatemers, yet their full characterization has been hindered by technical limitations in resolving complex infections. This study establishes a novel integrated workflow combining one-step PCR amplification with Oxford Nanopore Technologies (ONT) to sequence complete mitochondrial genomes from Eimeriidae and Haemosporida parasites. Successful assembly of 29 high-quality mitogenomes (12 Eimeriidae, 17 Haemosporida) from 15 samples, demonstrating the method's sensitivity. Comparative analyses revealed cryptic mixed/co-infections in 11 samples that were undetectable by Sanger sequencing, highlighting ONT's superior resolution for uncovering true parasite diversity. Phylogenomic reconstruction using the largest Eimeriidae dataset to date confirmed the monophyly of passeriform Isospora and identified a basal position for a novel Caryospora lineage from Ptyas major. In Haemosporida, analysis of 202 mitogenomes revealed non-monophyletic familial relationships. Selection analyses indicated predominant purifying selection in mitochondrial protein-coding genes of Eimeriidae. Our findings underscore the utility of long-read mitogenomics in elucidating complex infection dynamics and provide a scalable framework for biodiversity surveys of understudied apicomplexans parasites, with implications for understanding their evolutionary ecology and host-parasite interactions.

Early identification of people at risk of schistosomiasis infection is critical to interrupting disease transmission. We develop and validate an explainable machine learning prediction model that integrates demographic, behavioral, and environmental factors to identify these individuals. A total of 103,707 individuals were included to train and internally validate the model, and 16,574 individuals were used for external validation. The Random Forest (RF) model demonstrated the best discriminative performance among the five machine learning models evaluated. It accurately predicted schistosomiasis seropositivity in both internal validation (AUC = 0.943, F1 score = 0.809) and external validation (AUC = 0.897, F1 score = 0.770) and has been translated into a practical tool to support real-world application. Feature importance analysis indicated that the most significant predictors of schistosomiasis seropositivity included the presence of schistosomiasis symptoms, history of exposure to infected water, endemicity types of the village, gender, and village risk category. Furthermore, the SHapley Additive exPlanation (SHAP) method was employed to explain how these variables influence the prediction outcomes. This study provides a reference for early identification of high-risk populations and facilitates the translation of theoretical modeling studies into practical work applications.