Parasite最新文献

Blastocystis is one of the most prevalent intestinal protozoans, transmitted through the fecal-oral route. Domestic pigs and cattle serve as important reservoirs for Blastocystis, playing a crucial role in its transmission dynamics. In the present study, a PCR-sequencing tool based on the small subunit ribosomal RNA (SSU rRNA) gene was employed to investigate the prevalence and subtypes of Blastocystis in 456 pig and 302 cattle fecal samples collected in Hainan, the only tropical island province in China. The overall prevalence of Blastocystis in pigs and cattle was 30.3% (138/456) and 13.2% (40/302), respectively. Six known subtypes-ST5 (n = 139), ST21 (n = 18), ST26 (n = 10), ST10 (n = 7), ST23 (n = 2), and ST25 (n = 2)-were identified, including 138 ST5 from pigs, and 18 ST21, 10 ST26, 7 ST10, 2 ST23, 2 ST25, and 1 ST5 from cattle. A novel ST5 sequence (OQ048307) from a pig and a novel ST10 sequence (OQ048308) from a cow were detected. Our results suggest that livestock may be an important potential reservoir for zoonotic Blastocystis infection in humans and provided reliable data for future research on subtype distribution and infection control of this protozoan in tropical regions.

Following the ongoing inventory efforts conducted in Cambodia by the Medical and Veterinary Unit of the Institut Pasteur du Cambodge, and after intensive collection work in the eastern part of the country, we report 20 new mosquito species from Cambodia. Among these new records, none are considered to be of medical importance. Along with these new records, and incorporating 2 recently described species, we provide an updated checklist of the Culicidae fauna of Cambodia, which now includes 312 species, 43 of which are known to be of medical importance and are involved in the transmission of pathogens.

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.

Pentatrichomonas hominis is a protozoan parasite that infects the gastrointestinal tract of humans and mammals, causing abdominal pain and diarrhea. However, its presence in pigs and its potential as a pathogen causing diarrhea in piglets have not been well studied. This study aimed to investigate the prevalence of P. hominis in pigs and its potential for zoonotic transmission. A total of 406 pig fecal samples were collected from four pig farms located in Guangdong and Anhui Provinces. Fecal DNA extraction was carried out using a commercially available kit. A nested PCR methodology was employed to detect the presence of P. hominis infection. Samples that tested positive were subsequently subjected to sequencing, and the genetic characteristics of the 18S ribosomal RNA (rRNA) gene were analyzed. The overall infection rate of P. hominis was 34.98% (142/406), in Guangdong Province 28.47% (80/281), and in Anhui Province 49.60% (62/125). Among different age groups, suckling piglets had the highest infection rate at 40.24% (68/169). Genetic analysis of the P. hominis isolates showed that the PH-1 genotype was predominant and had a high degree of similarity to P. hominis sequences obtained from humans, cats, and pigs, indicating the potential for zoonotic transmission. The high infection rate and genetic diversity highlight the need for effective control measures in pig farming to reduce parasite transmission and zoonotic risk.

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.

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.