Parasites, hosts and diseases最新文献

Adult notocotylid flukes (Digenea: Notocotylidae) were recovered from the ceca of Pitalah ducks (Anas sp.) in Aceh Province, Indonesia. These flukes were morphologically characterized by a median ventral ridge with 2 lateral rows of ventral papillae and the absence of both a ventral sucker and pharynx, consistent with the characteristics of the genus Catatropis. They exhibited a genital pore located just posterior to the oral sucker, 10-11 pairs of ventral papillae, a deep and multi-lobed ovary and testes, a metraterm equal in length to the cirrus sac, and ceca bearing numerous diverticula; accordingly, they were identified as Catatropis indicus Srivastava, 1935. Adult specimens measured 3.01-3.77 mm (average 3.47 mm) in length and 0.98-1.21 mm (average 1.11 mm) in width (n=8). Uterine eggs measured 0.016-0.023 mm (average 0.019 mm) in length and 0.008-0.014 mm (average 0.012 mm) in width (n=20), each bearing 2 long polar filaments. These specimens resembled Catatropis vietnamensis Izrailskaia et al., 2019, and Catatropis pakistanensis Schuster and Wibbelt, 2012, sharing features such as a genital pore immediately posterior to the oral sucker and other morphological traits. However, they differed from C. vietnamensis by having a larger body, ceca with numerous diverticula, and a broader anterior distribution of vitelline follicles. They also differed from C. pakistanensis in possessing a longer esophagus and ceca with multiple diverticula. In 28S rDNA sequence analysis, our specimens showed 99.1% identity with both C. indicus and C. vietnamensis. In contrast, internal transcribed spacer 2 (ITS2) sequence comparisons revealed only 96.0%-96.1% identity with C. vietnamensis (no GenBank data available for C. indicus), suggesting that our specimens are phylogenetically distant from C. vietnamensis. This represents the first report of C. indicus from ducks in Indonesia. A brief review of Catatropis species is provided.

Cysteine proteases play key roles in the biology of Plasmodium parasites and are recognized as antimalarial drug targets. Because these enzymes are involved in diverse biological functions, precise regulation is required to prevent unnecessary damage to both parasites and hosts. In this study, we identified an endogenous inhibitor of cysteine protease of Plasmodium vivax (PvICP) and characterized its biochemical properties. PvICP was found to share highly similar structural characteristics with orthologous proteins from other Plasmodium species. Recombinant PvICP (rPvICP) expressed in Escherichia coli showed a broad range of inhibitory activity against falcipain family cysteine proteases, including vivapain-3, vivapain-4, falcipain-3, malapain-2, and malapain-4, with more potent inhibitory activity against vivapain-3 and vivapain-4. rPvICP's inhibitory activity was not significantly affected by pH, suggesting its broad biological functions. These findings provide new insights into PvICP and lay the groundwork for future studies exploring its biological significance and potential as a therapeutic target in malaria research.

Alpacas (Vicugna pacos), native to South America, were recently introduced to Korea, primarily for tourism-related activities. However, information on their parasitic infections in alpacas within the region are limited. This study aimed to investigate the longitudinal prevalence and diversity of gastrointestinal parasites in an alpaca herd on a single farm in Korea and to assess the potential risks for reinfection and interspecies transmission. Between June 2022 and June 2023 (excluding December 2022 and January 2023), fecal samples were collected monthly from a herd of 61 alpacas housed on a farm on Jeju Island, Korea. Coprological examination of 406 samples was performed using a modified McMaster technique, and parasites were identified morphologically. Six gastrointestinal parasite taxa were identified: strongyles, Trichuris sp., capillarids, Moniezia sp., Eimeria lamae, and Eimeria macusaniensis. The overall gastrointestinal parasite prevalence was 11.3%, with strongyles and Trichuris sp. most frequently identified. No seasonal trends were observed, and mixed infections were present in five animals. The prevalence was markedly lower compared with reports from Japan, Poland, and Australia, reflecting the restricted pasture access implemented by Korea's alpaca management systems, which are primarily tourism-oriented. Neither Nematodirus spp. nor zoonotic parasites were detected. This is the first longitudinal investigation of gastrointestinal parasites in alpacas in Korea. Although the overall prevalence was low, environmental contamination and the risk of reinfection are ongoing concerns. These findings highlight the need for routine surveillance, targeted parasite control, and consistent veterinary oversight, particularly as alpaca populations expand in Korea.

Balamuthia mandrillaris is a causative agent of granulomatous amebic encephalitis, a rare but often fatal condition. To investigate the role of T helper (Th) cell subsets in the immune response against B. mandrillaris, we examined 3 mouse strains with distinct immunological profiles: C57BL/6 (Th1-dominant), BALB/c (Th2-dominant), and ICR (balanced Th1/Th2). Mice were infected intranasally with 1×105 amoebae. Body weight and neurologic symtoms were monitored weekly, and cytokine expression was assessed biweekly over 6 weeks. Minimal weight loss and no mortality were observed in C57BL/6 mice, whereas BALB/c and ICR mice exhibited significant early and delayed mortality, respectively. Interleukin-17A expression was notably elevated in C57BL/6 mice compared with the other strains. These findings indicate that a robust Th17 response, particularly interleukin-17A production, is a critical component of the host defense against B. mandrillaris infection.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked recessive genetic disorder that can cause severe anemia in affected individuals exposed to oxidative stress. This risk is particularly relevant in patients treated with the antimalarial drug primaquine. In Myanmar, primaquine has been widely administered as a Plasmodium vivax malaria treatment; however, prevalence of G6PD deficiency among the population remains insufficiently characterized. This study investigated the prevalence of G6PD variants among various minority ethnic subgroups residing in Kachin State, Myanmar. Blood samples from 440 participants were analyzed; however, the Mahidol variant (G487A) was identified in 21 individuals (4.8%). A major limitation of this study was the absence of G6PD enzyme activity data to confirm whether the Mahidol variant induces G6PD deficiency.

The ovalbumin (OVA)-alum mouse model, which induces a Th2-biased immune response, is commonly used to study allergic airway inflammation. However, the artificial nature of this model limits its relevance to environmental or infection-related airway diseases. The free-living environmental protozoan Acanthamoeba is a potential trigger of airway inflammation, but its immune mechanisms remain largely unknown. To compare these 2 models of airway inflammation, this study carried out microarray-based transcriptomic analysis of lung tissue obtained from mice with OVA-alum treatment or intranasal Acanthamoeba exposure. Compared to controls, OVA-alum treatment induced broad transcriptional changes involving >2,900 probes (fold change ≥1.5); Acanthamoeba exposure led to a substantially weaker response, with <500 probes affected at the same threshold. Unlike the OVA-alum-treated group, the Acanthamoeba-exposed mice showed minimal overlap with only 5 genes significantly downregulated, suggesting a distinct immune activation profile. Downregulation of genes related to the immunoglobulin variable region (Ighv1-58 and Igkv3-10) and eosinophil function (Rnase2a) in the Acanthamoeba group suggest suppression of a typical Th2/humoral response. Heatmap and clustering analysis demonstrated clear separation between the Acanthamoeba, OVA-alum, and control groups. Taken together, these results suggest that Acanthamoeba induces a unique airway immune response that is markedly different from traditional Th2-dominant inflammation, and may be a more suitable model for studying environmentally-induced or infection-related respiratory diseases.

Toxoplasma gondii infections are ubiquitous in both animals and humans. Although seroprevalence data exist for pet dogs across multiple Chinese provinces, limited epidemiological information is available for T. gondii infection in pet dogs in subtropical China's Hunan Province. We examined T. gondii antibodies in pet dogs from Hunan Province using the indirect hemagglutination test. Logistic regression analyses were used to identify factors associated with T. gondii infection (season, sex, age, breed, and location). The overall seroprevalence was 10.8% (95% confidence interval (CI)=9.0-12.6) (118/1,092), with regional variations ranging from 8.0% (95% CI=4.2-11.8) to 21.1% (95% CI=8.1-34.0). Antibody titers followed a descending distribution: 42.3% (1:64), 30.5% (1:128), 20.3% (1:256), 5.1% (1:512), and 1.7% (1:1,024). The multivariate analysis identified the season (highest in summer: odds ratio=2.0, 95% CI=1.2-3.4) and age (>3 years: odds ratio=2.8, 95% CI=1.5-5.3) as factors independently associated with the outcome (P<0.05). These finding revealed the high seroprevalence of T. gondii infection in pet dogs in Hunan Province, subtropical China, highlighting the risk of zoonotic transmission. Therefore, effective measures should be taken to prevent and control toxoplasmosis in pet dogs in this province.

During the Edo period, Hachinohe Castle served as the residence of the Nanbu clan, the lords of the Hachinohe domain, and simultaneously functioned as the local government office. Although an analytical company reported on the soil samples from toilet remains within the castle, this study conducted a new analysis. Not only were Trichuris trichiura eggs found in Layer 21, but Metagonimus yokogawai and Dibothriocephalus nihonkaienesis eggs were also present. In Layer 20, which was initially thought to be free of parasitic organisms, T. trichiura, Ascaris lumbricoides, and M. yokogawai eggs were discovered. This paper discusses the differing results from previous studies, which demonstrate that the analytical methodology of Japanese archaeoparasitology is not yet well established, and suggests ways to improve it.