Parasite最新文献

Buxtonella sulcata is an alveolate ciliate protist, historically considered a commensal of the gastrointestinal tract of cattle. Despite the fact that its cysts are morphologically identical to those of Balantioides coli, molecular identification techniques have shed new light on its role as a pathogen. This work aimed to assess the presence of this ciliate in the population of dairy cattle on the Azorean island of Terceira by means of molecular analyses (ITS1-5.8S-ITS2 rRNA) of stool samples. A total of 116 samples were collected from adult Holstein-Friesian dairy cows, with no signs of gastrointestinal disease. A proportion of 49.1% of the samples were PCR-positive for Bu. sulcata, and 12 different genetic sequences were identified. These findings highlight the need for future research concerning the factors that influence the presence of Bu. sulcata in the gastrointestinal tract of dairy cows, the role of bovines as possible sources of infection, and the impact this ciliate may have on the health, welfare, and productivity of these animals.

While previous studies have examined the elevational limits of Ixodes ricinus in Central Europe, this study is the first to investigate the influence of slope orientation on tick distribution in Slovenia. Our results provide new insights into how two important microclimatic factors, temperature and humidity, vary between the northern and southern slopes, and how these differences affect the abundance of I. ricinus, a factor that has not been studied in this region before. We found that nymph density was highest on the southern slope at intermediate elevations (720 m) and increased with temperature. In contrast, fewer adult ticks were found on the southern slope compared to the northern slope, most of them at 720 m elevations. The significantly higher abundance of adult ticks on the northern slope is probably related to the cooler temperatures, higher relative humidity, denser ground vegetation and greater availability of hosts such as roe deer. Although these results are regionally specific, they contribute to a more comprehensive understanding of the ecological factors influencing the distribution of I. ricinus in Central Europe.

A comprehensive understanding of the prevalence and subtype distribution of Blastocystis infections among community participants in Thailand is essential to inform targeted public health interventions. This systematic review and meta-analysis aimed to estimate the overall prevalence of Blastocystis infections and to determine the distribution of subtypes among community participants in Thailand. Relevant studies on Blastocystis infections in community participants in Thailand were searched in PubMed, Embase, Scopus, Ovid, ProQuest, and the Thai-Journal Citation Index. The methodological quality of the included studies was assessed using the Joanna Briggs Institute critical appraisal tools. Prevalence estimates and subtype distributions were calculated using random-effects models. A total of 947 articles were identified, with 60 studies included in the systematic review and meta-analysis. The meta-analysis led to an estimated overall prevalence of Blastocystis infections in community participants in Thailand at 8.34% (95% CI: 5.48%-12.51%; I²: 98.2%; number of studies: 60; number of participants: 33,101). Meta-regression analysis showed no significant temporal trends in infection prevalence. The highest prevalence rates were observed in Eastern Thailand (13.54%) and Western Thailand (10.09%). Subtype analysis identified ST3 and ST1 as the most common subtypes, accounting for 50.05% and 23.50% of positive samples, respectively. The highest prevalence was reported in military personnel (29.87%), followed by orphans (29.01%). Improved use of molecular and culture-based diagnostic methods is recommended to enhance detection accuracy. Public health interventions should prioritize high-risk groups, such as military personnel and orphans, and address regional disparities to reduce the burden of Blastocystis infections.

Cutaneous leishmaniasis presents a significant challenge to public health due to its diverse clinical manifestations, resistance development, and treatment-related adverse effects. Here, we examined the efficacy of ivermectin, moxidectin (MOX), afoxolaner, and permethrin against all stages of Leishmania tropica and THP-1 cells. We also assessed the potential for resistance acquisition after 15 rounds of artificial selection. To elucidate the mode of action of MOX, we employed RNA sequencing, molecular dynamics simulation, and chloride flux assays. Additionally, we evaluated the therapeutic index of MOX using the Galleria mellonella infection model. MOX demonstrated the highest selectivity index against leishmaniasis (promastigotes: 0.58 μM; amastigotes: 0.96 μM; host cells: 60.29 μM). Moreover, MOX exhibited the lowest resistance acquisition in both promastigotes and intracellular amastigotes after 15 rounds of artificial selection, with resistance ratios of 17.23 and 4.59, respectively. Post-exposure to MOX, differential gene expression profiles showed both stage-specific and stage-unspecific enrichment of gene families involved in crucial biological processes. Moreover, molecular dynamics simulations revealed a potential neutralizing effect of MOX on the chloride channel of L. tropica. Specifically, MOX binds to the selectivity filter, potentially disrupting the osmotic equilibrium and thereby killing the parasite. The in vivo introduction of MOX significantly inhibited the growth of L. tropica in G. mellonella larvae, resulting in decreased rates of mortality and melanization. These findings indicate that MOX is a promising candidate for the treatment of L. tropica infections, warranting further investigation and potential consideration for clinical use.

Giardia duodenalis and Cryptosporidium spp. are significant zoonotic parasites that cause diarrhea and affect a diverse range of hosts. This study aimed to investigate the infection rates of these parasites in captive wildlife at Beijing Zoo. A total of 445 fecal samples were collected and analyzed using PCR. The infection rate of G. duodenalis was 3.82% (17/445), with assemblage A (n = 1), assemblage B (n = 13), and assemblage E (n = 3) identified. The infection rate of Cryptosporidium spp. was 0.22% (1/445), with only one instance of C. ryanae identified from cattle (Bos taurus). To the best of our knowledge, this study enhances the understanding of the host range of G. duodenalis in captive wildlife within China, highlighting infections in Corsac Fox (Vulpes corsac), Indian Rhinoceros (Rhinoceros unicornis), and Giraffe (Giraffa camelopardalis). These findings indicate that the infection rates of G. duodenalis and Cryptosporidium spp. in captive wildlife at Beijing Zoo are low, while showing that the known host range of G. duodenalis is expanding.

Congenital toxoplasmosis is a fetal infection resulting from the transplacental transmission of Toxoplasma gondii in mothers who seroconvert during pregnancy. Neonatal diagnosis has recently been improved through the identification by L'Ollivier et al. (2012) and Peyclit et al. (2023) of a pathognomonic marker for congenital toxoplasmosis: the IgM triplet, corresponding to three high molecular weight bands of 75, 90, and 100 kDa, respectively found on the mother-child immunoblot pair profile. This is a new concept, as these three IgM bands reflect an immune response targeting proteins involved in vertical transmission of T. gondii. These proteins may be T. gondii secreted or non-secreted effectors implicated in host cell invasion, immune modulation, and parasite virulence. In this study, immunoproteomic techniques allowed us to identify thirty-two relevant protein spots on immunoblot, including four specifically associated with the IgM triplet. Protein identification by LC-MS/MS revealed several T. gondii proteins as strong candidates for the IgM triplet. Each of these proteins is, directly or indirectly, involved in cellular invasion and may also play a role in transplacental transmission of T. gondii. Identifying these proteins opens several avenues of therapeutic research that could improve the management of congenital toxoplasmosis.

Ticks are ectoparasites harboring complex microbial communities, typically dominated by nutritional symbionts that produce B vitamins and sometimes including pathogens affecting human and animal health. However, ticks also host a variety of commensal microbes whose diversity remains poorly documented. In this study, we isolated and identified culturable bacteria and fungi associated with various tick species from the genera Ixodes, Dermacentor, Amblyomma, and Ornithodoros, collected from their natural habitats or hosts in France and French Guiana. A total of 111 bacterial and 27 fungal isolates were obtained which were then identified using both molecular and morphological approaches. Substantial fungal diversity was observed in a few ticks, whereas culturable bacteria displayed a broader distribution and diversity across tick species. Interestingly, the diversity of culturable bacteria and fungi revealed a microbiome structure that reflected the ecological niches of the tick host, indicating habitat-specific microbial associations and a potential ecological role in tick biology. The isolation of common gut bacteria of other arthropods, as well as the isolation of a viable entomopathogenic fungus, underscores the potential influence of these microbes on tick biology.

Baylisascaris schroederi McIntosh, 1939 (Ascarididae), a nematode specific to giant pandas (Ailuropoda melanoleuca), is a major health threat, particularly to wild populations. A 20-year-old wild adult female giant panda rescued from a Chinese nature reserve died with a 2-month history of emaciation and weakness. Necropsy was performed. Grossly, the giant panda was very thin with minimal fat stores throughout, and marked serous atrophy of fat around the kidneys. Mesenteric edema was very pronounced in the posterior intestine. The abdominal cavity contained approximately 5 L of orange-yellow, translucent, low-viscosity fluid. There were ca. 1,660 robust ascarids occupying the lumen of the esophagus, stomach, and intestines. Microscopically, the intestine showed moderate necrotizing and eosinophilic enteritis with adult nematodes, consistent with an ascarid. PCR and sequencing confirmed that the ascarid species was B. schroederi. This case highlights a fatal B. schroederi infection in a wild giant panda, with malnutrition and possible multiple organ failure identified as the primary causes of death.

Cryptosporidium spp. are important zoonotic parasites that can cause moderate to severe diarrhea in humans and animals. However, the epidemiological data of Cryptosporidium in sika deer in China need to be updated. In this study, a total of 466 fecal samples were collected from sika deer in Shandong, Jilin, Liaoning, and Heilongjiang provinces. Nested PCR was used to amplify the SSU rRNA gene to detect Cryptosporidium spp. The results showed that the overall infection rate of Cryptosporidium spp. was 14.81%, with no significant differences among regions (p = 0.05). The highest infection rate was found in Heilongjiang Province (23.60%) and the lowest in Jilin Province (10.71%). The infection rate in summer (23.61%) seemed higher than that in autumn (13.20%), but the difference was not statistically significant (p = 0.30). Notably, young sika deer showed a significantly higher infection rate (28.21%) compared to adults (10.32%) (p < 0.0001). Sequence analysis identified two Cryptosporidium species/genotypes: Cryptosporidium deer genotype (98.55%) and Cryptosporidium ubiquitum (1.45%). Subtyping revealed that the C. ubiquitum isolate belonged to the zoonotic XIIa subtype. These findings provide new insights into the prevalence and genetic diversity of Cryptosporidium in sika deer and suggest that sika deer may act as a potential reservoir for zoonotic Cryptosporidium transmission.

The spread of resistance to insecticides, such as pyrethroids, in Aedes vectors increases the risk of spread of arboviral diseases. In Gabon, the insecticide resistance profiles of Ae. aegypti and Ae. albopictus species remain poorly known. During a study to monitor the dynamics of Aedes populations in Franceville, in south-east Gabon, the resistance profiles of these two species to pyrethroids, organophosphates and carbamates were assessed. Susceptibility tests on adults and synergist tests with piperonyl butoxide (PBO) were carried out as per the World Health Organization protocol. The results showed that Ae. aegypti and Ae. albopictus were susceptible to permethrin, pirimiphos-methyl and bendiocarb. However, both species were resistant to deltamethrin (mortality: 67% for Ae. aegypti; 33% for Ae. albopictus). Exposure to a 5-fold dose of deltamethrin increased mortality to 100% and 91% for Ae. aegypti and Ae. albopictus, respectively. Resistance to alpha-cypermethrin was also recorded (mortality: 82% for Ae. aegypti; 64.6% for Ae. albopictus). Pre-exposure to PBO resulted in the restoration of susceptibility to deltamethrin and alpha-cypermethrin for Ae. aegypti, and a significant increase in mortality for Ae. albopictus. These data provide the first evidence of pyrethroid resistance in Aedes in Gabon and could help to establish more effective control measures against arbovirus vectors.