Parasitology最新文献

Elevated levels of IL-6 in plasma are associated with the severity of visceral leishmaniasis (VL). The clinical manifestations of VL vary among patients, influenced by host factors and the virulence of the Leishmania infantum parasite. Considering that severe VL may result from an exaggerated inflammatory response, this study investigated whether IL-6 could serve as a biomarker to identify pro-inflammatory virulence factors. We conducted a genome-wide association study (GWAS) analysis on L. infantum isolates from patients with VL, whose IL-6 concentrations were measured. The analysis revealed that the relationship between IL-6 levels and clinical outcomes (survival vs mortality) had an area under the curve (AUC) of 0.67 (95% CI 0.52–0.81). A cut-off of 391.7 pg mL⁻¹ for IL-6 was established to conduct a logistic regression analysis. We identified 10 029 single nucleotide variants (SNVs) across 62 genomes, resulting in 6,948 SNVs after filtering, of which 6,341 are located in protein-coding regions. The association analysis with PLINK identified 722 variants, of which 35 showed significant associations, with odds ratios ≥3.3, primarily in coding regions. These findings demonstrate that IL-6 levels tended to be associated with the fatal outcome of VL and highlight 35 novel genetic variants that could serve as potential biomarkers for prognosis. Further research into the biological role of these variants may lead to new therapeutic targets and improve the clinical management of VL, especially in identifying high-risk patients.

Identifying factors that drive among-individual variation in mixed parasitic infections is fundamental to understanding the ecology and evolution of host–parasite interactions. However, a lack of non-invasive diagnostic tools to quantify mixed infections has restricted their investigation for host populations in the wild. This study applied DNA metabarcoding on parasite larvae cultured from faecal samples to characterize mixed strongyle infections of 320 feral horses on Sable Island, Nova Scotia, Canada, in 2014 to test for the influence of host (age, sex and reproductive/social status) and environmental (location, local density and social group membership) factors on variation. Twenty-five strongyle species were identified, with individual infections ranging from 3 to 18 species with a mean richness (±1 s.d.) of 10.8 ± 3.1. Strongyle eggs shed in faeces were dominated by small strongyle (cyathostomins) species in young individuals, transitioning to large strongyles (Strongylus spp.) in adults. Egg counts were highest in young individuals and in the west or centre of the island for most species. Individuals in the same social group had similar parasite communities, supporting the hypothesis that shared environment may drive parasite assemblages. Other factors such as local horse density, sex, date and reproductive/social status had minimal impacts on infection patterns. This study demonstrates that mixed infections can be dynamic across host ontogeny and space and emphasizes the need to consider species-specific infection patterns when investigating mixed infections.

The functional diversity structure of a community can be represented as a combination of three additive components (species dominance D, functional redundancy R, and functional diversity Q) (DRQ approach in which different facets of functional differences between species are considered simultaneously). We applied this concept to assemblages of fleas and gamasid mites parasitic on small mammals at continental (across regions of the Palearctic) and regional (across sampling sites in Slovakia) scales and asked: What are the relative effects of host species, biome/habitat type, and geographic locality on the DRQ composition of a parasite assemblage? At the continental scale, regions were partitioned according to predominant biome or geographic position in a continental section. At the regional scale, sampling sites were partitioned according to habitat type or geographic locality. We tested for differences in the functional diversity structure (measured as the DRQ composition) of an ectoparasite assemblage (a) within a host species between biomes/habitat types or continental sections/localities and (b) between host species within a biome/habitat type or a continental section/locality. At both scales, the functional diversity structure of both flea and mite assemblages differed mainly between host species within a biome/habitat or geographic regions/locations, whereas differences in the DRQ composition between biomes/habitats or geographic regions/locations were only detected in a few host species. We compare our results with the results of earlier studies and conclude that the DRQ approach has an advantage over a single diversity metric and allows a better understanding of spatial variation in different facets of ectoparasite diversity.

The migration of Mongolian gazelles (Procapra gutturosa) poses a potential risk of outbreak for zoonotic intestinal protozoan parasite infections. This study aims to investigate the infection status of zoonotic intestinal protozoan parasites in these migratory Mongolian gazelles. We collected 120 fecal samples from Mongolian gazelles during their migration from Mongolia to China in December 2023. These samples were analysed using amplification and sequencing of partial SSU rRNA genes to detect the 4 presence of zoonotic intestinal protozoan parasites and characterize their genotypes. Our analysis revealed the presence of several zoonotic intestinal protozoan parasites in the sampled Mongolian gazelles. Cryptosporidium spp. was detected in 14.17% (17/120) of the samples, followed by Cystoisospora belli in 13.33% (16/120), Blastocystis sp. in 16.67% (20/120) and Cyclospora cayetanensis in 30.00% (36/120). Moreover, we identified novel host-adapted genotypes of Cryptosporidium spp. and C. belli, as well as the presence of ST2 and ST13 Blastocystis sp. subtypes, while distinct genotypes were found in Blastocystis sp. and C. cayetanensis. This study revealed the status of 4 prevalent zoonotic intestinal protozoan parasite infections in Mongolian gazelles and provided crucial insights into their characteristics. The prevalence of these parasites in the population highlights the potential risk of cross-border transmission of infectious diseases associated with long-distance migration. Furthermore, the identification of novel genotypes contributes to our understanding of the genetic diversity and adaptation of these parasites. These findings can inform the development of protective measures to mitigate the impact of these infections on the health and survival of Mongolian gazelles.

Paleoparasitological studies have made important contributions to our understanding of the past epidemiology of parasites, infection in past populations and lifestyle in the past. In some cases, these ancient parasites can also provide evidence for long distance travel or migration of people in the past. Three sediment samples from a 15th–16th c. CE latrine from the Spanish nation house in Bruges, Belgium were analysed for preserved helminth eggs using microscopy. Bruges was a major trading centre in medieval Europe, thus it was home to a large merchant population with extensive trading networks. Paleoparasitological analysis revealed a preserved parasite egg from Schistosoma mansoni, which causes intestinal schistosomiasis. Roundworm, whipworm, liver fluke and Taenia tapeworm eggs were also found in the latrine which is consistent with parasites previously found in the local population in the medieval period. These new data provide direct evidence for the movement of S. mansoni outside of its endemic area. Today the vast majority of S. mansoni infections occur in Sub-Saharan Africa, with additional endemic areas in the Arabian peninsula and South America. The introduction of S. mansoni into South America is proposed to have occurred relatively recently in human history, as the result of forced movement of people from Africa to the Americas with the Atlantic slave trade. Thus, this infection may have occurred in a merchant who acquired the parasite during trade voyages to Africa or in an individual living in Africa who migrated to Bruges.

Amphalius spirataenius belongs to Arthropoda, Insecta, Siphonaptera, Ceratophylloidea, Ceratophyllinae, Amphalius. Only 2 species from the subfamily Ceratophyllinae have been sequenced for mitogenomes to date. The genus Amphalius mitogenome research was still blank. The A. spirataenius mitogenome was determined, annotated and analysed for the first time in this study. The 14 825 bp long genome has the typical metazoan of 37 genes with insect ancestral genome arrangement pattern. There was no significant difference in codon usage of 13 protein-coding genes: UUA, UCU, GUU, ACU and GCU were the most frequently used codons. It was found that the reason for codon preference mainly contributed to natural selection base on PR2, ENC-plot and neutrality curve analysis. Evolutionary rate, conserved sites, variable sites and nucleotide diversity analysis indicated that nad6 of A. spirataenius had the fastest evolutionary rate, while cox1 had the slowest evolutionary rate. Phylogenetic trees were reconstructed based on 13 protein-coding genes and 2 rRNA genes datasets using Bayesian inference and maximum likelihood method. The phylogenetic tree supported that both Siphonaptera and Mecoptera were monophyletic, and were sister groups to each other. This study filled gap of the genus Amphalius mitogenome sequences and was of great significance for understanding evolution of the order Siphonaptera.

Natural infection by Trichinella sp. has been reported in humans and more than 150 species of animals, especially carnivorous and omnivorous mammals. Although the presence of Trichinella sp. infection in wild boars (Sus scrofa) has been documented worldwide, limited information is known about Trichinella circulation in farmed wild boars in China. This study intends to investigate the prevalence of Trichinella sp. in farmed wild boars in China. Seven hundred and sixty-one (761) muscle samples from farmed wild boars were collected in Jilin Province of China from 2017 to 2020. The diaphragm muscles were examined by artificial digestion method. The overall prevalence of Trichinella in farmed wild boars was 0.53% [95% confidence interval (CI): 0.51–0.55]. The average parasite loading was 0.076 ± 0.025 larvae per gram (lpg), and the highest burden was 0.21 lpg in a wild boar from Fusong city. Trichinella spiralis was the only species identified by multiplex polymerase chain reaction. The 5S rDNA inter-genic spacer region of Trichinella was amplified and sequenced. The results showed that the obtained sequence (GenBank accession number: OQ725583) shared 100% identity with the T. spiralis HLJ isolate (GenBank accession number: MH289505). Since the consumption of farmed wild boars is expected to increase in the future, these findings highlight the significance of developing exclusive guidelines for the processing of slaughtered farmed wild boar meat in China.

Galba truncatula is one of the most distributed intermediate hosts of Fasciola hepatica across Europe, North Africa and South America. Therefore, understanding the environmental preferences of this species is vital for developing control strategies for fascioliasis and other trematodes such as Calicophoron daubneyi. This systematic literature review evaluates the current understanding of the snail's environmental preferences to identify factors which might aid control and areas where further research is needed. Searches were conducted using Google Scholar and PubMed and included papers published up to August 2023. After filtration, 198 papers with data from 64 countries were evaluated, and data regarding habitat type and habitat pH were noted, along with any other information pertaining to the snail's environmental preferences. The results show that G. truncatula can survive in a diverse range of climates and habitats, generally favours shallow slow-moving water or moist bare mud surfaces, temperatures between 10 and 25°C and was found in habitats with a water pH ranging from 5.0 to 9.4. However, there is limited understanding of the impact of several factors, such as the true optimum pH and temperature preferences within the respective tolerance limits or the reason for the snail's apparent aversion to peatland. Further research is needed to clarify the impact of biotic and abiotic factors on the snail to create robust risk assessments of fluke infection and assess opportunities for environmental control strategies, and for predicting how the snail and fluke transmission may be impacted by climate change.

Echinococcosis is a parasitic invasion caused by a cestode of the genus Echinococcus. Kyrgyzstan is a country in Central Asia known for an extremely high incidence of echinococcosis. A total of 10 093 subjects were screened in the Osh, Naryn and Batken regions of Kyrgyzstan in 2015–2017 by ultrasound and questioned for potential risk factors. Cystic echinococcosis (CE) prevalence (combined newly diagnosed and post-surgery cases) ranged between 0.2 and 25.2% across the study regions. Typical factors, such as dog or livestock ownership, weakly affected CE risk (odds ratio [OR] = 1.18–1.83). Use of water from a well and owning a cat had a greater effect on CE risk (OR = 2.02–2.28). The risk factors of CE were highly dissimilar among the study regions, with patterns not always compatible with classical biohelminthosis transmission routes (no risk from livestock in certain areas, significant risk from using well water, owning cats). Therefore, the CE epidemic in Kyrgyzstan is not holistic in terms of potential mechanisms and risk factors, and certain areas can greatly benefit from preventive measures that will have limited efficiency elsewhere.