Parasitology Research最新文献

Fish in wild and cultured populations may be infected with numerous types of pathogens but the host responses vary dependent on both host and parasite species. The present study demonstrates how an experimental infection with endoparasitic nematode larvae (Anisakis simplex) induces cellular and humoral immune responses in rainbow trout Oncorhynchus mykiss. The nematode larvae invaded the peritoneal cavity of the fish following oral administration and became encapsulated by a range of host cells including macrophages, neutrophils, mast cells, fibroblasts, and lymphocytes. The main part (92.7%) of the recovered larvae was located in the body cavity and 51.3% along the pyloric caeca with only few in or on the stomach, liver, spleen, swim bladder, and musculature. The cellular reaction was documented by transmission electron microscopy (TEM) and histochemistry. Real time quantitative PCR (qPCR) showed that a series of immune-relevant genes in the host spleen became regulated by the infection. Thus, A. simplex induced downregulation of immune-genes (encoding IgD and lysozyme) and upregulation of the gene encoding the immune-regulating cytokine IL-10. Nematode molecules influencing the antiparasitic host reactions are discussed.

The present study evaluated the efficacy of albendazole in treating soil-transmitted helminth infections among school children aged 6 to 15 years in three districts of Central Tigray, Ethiopia. A total of 1020 elementary school children were screened from three schools using Kato-Katz and microscopic detection techniques. Of these, 35.2% (359/1020) of children were infected with one or more soil-transmitted helminths and were treated with 400 mg albendazole. The efficacy of the drug was assessed by measuring the percentage reduction in helminth egg counts using Kato-Katz. Albendazole was most effective against hookworm, with overall 94.1% egg reduction rates (ERRs), 3 weeks post-treatment followed by A. lumbricoides and T. trichiura, with overall ERRs of 83.9% and 31%, respectively. Analysis of factors affecting albendazole treatment success revealed that the age of respondents, source of drinking water, and infection intensity at baseline were significant predictors of treatment success. School children 6-8 years old showed higher ERRs, while those using stream water for drinking purposes and with multiple parasite infections at baseline had lower probability of ERRs. These findings demonstrate the varying efficacy of albendazole across different STH infections and geographical locations, calling a more refined research to enhance treatment approaches for A. lumbricoides and T. trichiura. This study underscores the need for context-specific therapeutic intervention to enhance treatment success in endemic areas.

The purpose of this study was to evaluate the genetic diversity of ticks from free-ranging hosts in some areas of Qinghai Province and perform a phylogenetic analysis among different geographical populations, in order to establish a foundation for the prevention and control of ticks and tick-borne diseases in Qinghai Province. In March and April 2024, a total of 935 ticks were collected from goats, yaks, and horses in Jianzha and Haiyan counties. The tick species were identified by taxonomic key and 16S ribosomal RNA (16S rRNA) sequencing, and haplotype analysis, phylogenetic tree construction, and genetic differentiation index were performed using DNASP v.6, Popart, MEGA 11, and Arlequin v.3.5 software. The 935 collected tick samples belonged to three categories: Haemaphysalis spp., including H. qinghaiensis (n = 525) and H. danieli (n = 199); Dermacentor spp., containing D. nuttalli (n = 8) and D. silvarum (n = 201); and Hyalomma marginatum (n = 2), which was first identified in Qinghai Province. Haplotype and nucleotide polymorphism analyses indicated that there were 19 haplotypes in H. danieli, with haplotype H13 as the dominant haplotype (119/199); six haplotypes in D. nuttalli, with H3 and H4 haplotypes as the dominant haplotypes (4/8); and 20 haplotypes in D. silvarum, with H1 as the dominant haplotype (149/201). The genetic differentiation of D. silvarum, H. danieli, and D. nuttalli occurred both within and among populations. The phylogenetic analysis revealed that the tick species obtained from this study formed clades with the corresponding tick populations. These findings show that the tick species in Jianzha and Haiyan in Qinghai Province underwent population expansion and exhibited enhanced genetic diversity, providing a vital basis for understanding the distribution of ticks and tick-borne diseases in Qinghai Province.

Toxocariasis is a parasitic infection that poses significant health risks to children, particularly in marginalised populations with limited access to sanitation and healthcare. This study aimed to compare the occurrence of toxocariasis in early childhood between a group of children from the Slovak majority population and from marginalised Roma communities (MRCs), explore potential risk and protective factors and the association with mental health difficulties in early childhood. Cross-sectional data were obtained from mothers, and blood samples of their children aged 14-21 months were collected during the first wave of the longitudinal RomaREACH study. A total of 88 blood samples from children were analysed: 49 children from the Slovak Majority population and 39 from MRCs. Anti-Toxocara canis IgG antibodies were detected in serum samples using an enzyme-linked immunosorbent assay (ELISA). Though it was not statistically significant, seropositivity for Toxocara canis was more often observed in children from MRCs (35.9%) than in the majority population (20.4%). The absence of running water in households significantly increases the risk of Toxocara infection in children, whereas a longer duration of breastfeeding decreases it. Children seropositive for Toxocara canis showed higher levels of early mental health difficulties even when controlled for MRC residence. These results indicate the need for integrated public health interventions targeting parasitic infections in susceptible populations. Improving access to sanitation, promoting breastfeeding, and strengthening the preventive and educational role of early childhood health services are critical strategies to reduce the risk of exposure to Toxocara spp. eggs and mitigate its potential impact on child health and development.

Rhipicephalus sanguineus is a tick species characterized by high intraspecific variability, even among populations occupying the same habitats. This study investigated whether two distinct phenotypes of R. sanguineus, collected from four geographically separated regions, are associated with specific nucleotide polymorphisms in the mitochondrial cox1 and 16S rRNA gene regions-markers commonly employed in phylogenetic analyses. Morphometric analysis based on established criteria clearly distinguished two morphotypes-Morphotype 1 and Morphotype 2-with statistically significant differences. This morphological differentiation was supported by phylogenetic and genetic divergence analyses, primarily based on mitochondrial cox1 sequences, which revealed six polymorphic sites within the analyzed fragment. Among the identified haplotypes, two-Haplotype 2a and Haplotype 2b-were consistently associated with Morphotype 2. This genetic segregation was confirmed in extended analyses including reference isolates (morphologically and/or genetically defined either as R. sanguineus or R. hibericus). These analyses also demonstrated a close phylogenetic relationship between Morphotype 1 and the R. sanguineus neotype, as well as between R. hibericus and both morphotypes. Although the 16S rRNA marker exhibited lower resolution, it still effectively distinguished the two morphotypes and corroborated the haplotype assignments established by the cox1 phylogeny. The observed genetic divergence (p-distance of 1% in cox1 gene) and the phylogenetic relationship between R. sanguineus and R. hibericus confirmed that R. sanguineus is a polymorphic species, with well-defined haplo-morphotypes, and that R. hibericus is not genetically distinguishable from R. sanguineus.

Congenital transmission is a key route for Trypanosoma cruzi infection, yet the cellular mechanisms enabling congenital transmission remains poorly understood. This study evaluated the susceptibility of different trophoblast cell line models to T. cruzi infection and compared infectivity patterns among TcI strains compared to Y strain (TcII). The BeWo cell line was used to model cytotrophoblast (CT) and syncytiotrophoblast (ST) cells, while the HTR-8/SVneo cells modeled extravillous trophoblasts (EVTs). Three Colombian TcI strains and one TcII strain were cultured and differentiated into infective trypomastigotes. Infection rates, intracellular parasite replication, trypomastigote release, cell viability, hormone secretion, apoptosis, and ultrastructural characteristics were studied. Significant differences in infection susceptibility among trophoblast types were observed. BeWo CT-like cells were highly permissive to infection, whereas ST-like cells exhibited strong resistance, potentially due to intrinsic defense mechanisms. HTR-8/SVneo showed moderate susceptibility, supporting persistent replication and trypomastigote release. Infection impaired cell viability and disrupted endocrine functions such as hCG secretion, with cell-type-specific effects. Parasite strains also differed in infectivity. Strain Υ demonstrated high infectivity and cytotoxic effects. In contrast, SN3 and GAL61S strains exhibited slower intracellular development and lower release of trypomastigotes. Strain SA showed early infectivity but limited replication. These findings highlight the differential susceptibility of trophoblast subtypes to T. cruzi infection and the variability in strain virulence. Further insight into placental defense mechanisms and parasite-host interactions is essential for understanding congenital transmission and developing targeted preventive strategies.

Bats are recognized as key reservoir hosts for a variety of trypanosomes, yet their full diversity and host associations remain underexplored in Africa. In this study, we investigated the diversity and phylogenetic relationships of trypanosomes infecting bats in Uganda and the Central African Republic (CAR) using molecular tools. A total of 22 distinct genotypes were identified, clustering into seven well-supported phylogroups, including known species such as Trypanosoma dionisii, T. livingstonei, T. vespertilionis, and T. erneyi, alongside several novel lineages. Notably, T. erneyi was restricted to Mops condylurus, reaffirming its narrow host specificity. Phylogenetic analyses revealed substantial intraspecific diversity in T. livingstonei and T. vespertilionis, suggesting potential cryptic species, while T. dionisii exhibited limited genetic divergence across a broad geographic range. Intriguingly, a unique and highly diverse phylogroup was detected exclusively in fruit bats (Pteropodidae) from Uganda, closely related to the Australian T. teixeirae, and likely represents a novel species. The absence of trypanosomes in fruit bats from CAR, despite similar sampling effort, hints at ecological or evolutionary factors shaping parasite distribution. Our findings expand the current knowledge of bat-trypanosome diversity and highlight the importance of African bat populations in understanding the evolutionary dynamics of trypanosomes.

Hydatid disease or hydatid cysticercosis is a zoonotic disease caused by the tapeworm Echinococcus granulosus. Dogs are definitive hosts, while humans and livestock, such as sheep and cattle, are intermediate hosts for the parasite. Infection occurs when contaminated food is ingested. This neglected disease is prevalent in temperate regions, mainly where sheep farming is common, with seroprevalence in Iran ranging from 1.6% to over 20%. The current study assesses human CE prevalence among various demographics in East Azerbaijan, Iran. This cross-sectional study was conducted on 1912 individuals aged 10 or older from urban, rural, and nomadic populations. To identify Anti-E. granulosus IgG, the ELISA technique was employed. Probable risk factors were recorded using a questionnaire prior to serum collection. At last, the multiple logistic regression model was employed to assess the correlation between seroprevalence rates and variables. The study found a seroprevalence rate of approximately 4% (95% CI 3.15%-4.91%), with 77 individuals testing positive for hydatidosis. Significant risk factors included nomadic and rural living conditions (OR = 2.059, 95% CI = 1.270-3.337), contact with dogs (OR = 2.30; 95% CI 1.42-3.75), and occupations in agriculture, animal husbandry, and housekeeping (OR = 1.244, 95% CI = 1.068-1.450). Results directed towards actual living conditions being the main contributors to the prevalence of the disease and occupational exposure reflect the vulnerability of the nomads due to their limited access to healthcare and hygiene measures. The present study indicates the urgent need to undertake targeted public health interventions that improve awareness and preventive strategies among high-risk groups.

This pilot study is the first in Iran that evaluates the effectiveness of thermotherapy compared to intralesional Glucantime® in the treatment of cutaneous leishmaniasis caused by Leishmania tropica. Forty patients with cutaneous leishmaniasis were separated into two groups, each consisting of 20 patients. The control group received intralesional Glucantime® weekly for 8 weeks, while the other group received a single session of thermotherapy for each lesion using ThermoMedTM model 1.8. The patients were monitored for 6 months, during which the outcomes were evaluated by considering the dimensions, consistency, and rates of remission of the lesions. The terms "initial remission" and "complete remission" were clearly defined, and any instances of therapy failure were documented. The statistical analysis was conducted using SPSS 24.0, employing independent t-tests, chi-square tests, and ANOVA. Both treatment groups exhibited considerable decreases in lesion size and enhanced texture, with no statistically significant differences. Nevertheless, the group that underwent thermotherapy demonstrated a more significant decrease in lesion size and improvement in texture after 6 months. The remission rates were similar; however, Glucantime® achieved a faster remission. No significant side effects were recorded in either group. The present study showed that thermotherapy was equally effective as intralesional Glucantime® in treating anthroponotic leishmaniasis. Thermotherapy can be considered as an alternative, especially when Glucantime® cannot be used, even though it requires further research.

Brazil is a major pig-producing country with production systems that include both industrial and family farms. In these facilities, parasitic diseases present an obstacle to production. This study aimed to estimate the prevalence and risk factors of the gastrointestinal parasites that infect pigs as well as to provide information for producers through extension activities. Visits were made to 15 pig farms in cities in the states of Rio de Janeiro and Minas Gerais. Fecal samples were collected, questionnaires administered, and extension activities conducted. A total of 1,148 samples were collected: 299 from family farms and 849 from industrial farms. Stool samples were subjected to direct examination, sedimentation, flotation, and FLOTAC techniques. The most frequently detected parasites were cysts and trophozoites of the Ciliophora group, non-sporulated coccidian oocysts, eggs of Trichuris suis, strongyles, Strongyloides ransomi, and Ascaris suum. Statistical analysis revealed significant differences (p ≤ 0.05) in parasite presence and egg counts, with family farms exhibiting higher parasite burdens (p < 0.0001). Several risk factors were associated with the frequency of parasite infection, including the arrangement of watering systems on the pen floors and the type-or absence-of antiparasitic medication provided. Among the extension activities implemented, the "happy pig and sad pig" activity and "homework correction" stood out. These results highlighted the need for improvements in national pig production. This includes the development of programs offering credit, assistance, and training for pig producers to aid in the control of these parasites, with a focus on production and animal welfare.