Parasites, hosts and diseases最新文献

The Oriental stork (Ciconia boyciana Swinhoe, 1873) is an endangered species, with active restoration efforts ongoing in Korea. Despite the ecological importance of host-specific parasites, such as chewing lice (Phthiraptera), information on the chewing lice fauna associated with C. boyciana in Korea remains unclear. Previous records of 2 chewing louse species from the host have been questioned due to potential misidentification. To clarify the chewing lice fauna of the host, we conducted a survey of captive C. boyciana at Yesan Oriental Stork Park, Korea, in October 2022. Morphological identification of collected louse specimens revealed 3 species: Neophilopterus incompletes (Denny, 1842), Ardeicola ciconiae (Linnaeus, 1758) and Colpocephalum zebra Burmeister, 1838. These species are typical ectoparasites of Ciconiiform birds and represent the first verified louse records of chewing lice from C. boyciana in Korea. Unlike with a previous report, Cuclotogaster heterographus (Nitzsch, 1866) and Anaticola anseris (Linnaeus, 1758) were not detected. Our findings provide an updated checklist of chewing louse species for C. boyciana in Korea, contributing to a more accurate understanding of host-parasite associations and supporting future conservation efforts for both the host and its associated parasite fauna.

Naegleria fowleri is a free-living amoeba that can cause primary amebic meningoencephalitis (PAM), a very serious infection of the central nervous system. Early diagnosis of PAM is challenging, and the condition is almost always fatal. In this study, we conducted 2-dimensional gel electrophoresis (2-DE) analysis using N. fowleri trophozoite lysates and conditioned media to identify preferentially secreted proteins. As a result of the 2-dimensional gel electrophoresis analysis, 1 protein was found to increase, 5 proteins were found to decrease, 3 proteins showed a qualitative increase, and 15 proteins showed a qualitative decrease in the conditioned media compared to the proteins in the trophozoite lysates. Using cDNA from N. fowleri, Acanthamoeba castellanii, and Balamuthia mandrillaris, all of which can cause encephalitis, real-time PCR was performed on 5 genes corresponding to the p23-like domain-containing protein, cystatin-like domain-containing protein, fowlerpain-2, hemerythrin family non-heme iron protein, and an uncharacterized protein. The results showed that all 5 genes were highly expressed in N. fowleri. In animal models infected with N. fowleri resulting in PAM, real-time PCR analysis of brain tissue revealed significant overexpression of the p23-like domain-containing protein and fowlerpain-2. These results suggest that the 2 secreted proteins could provide valuable insights for developing antibody-based or molecular diagnostic methods to detect N. fowleri in patients with PAM.

Hepatic alveolar echinococcosis (HAE), a life-threatening zoonosis, poses formidable surgical challenges when involving critical vasculature. Herein, we reported the periprocedural management dilemmas in radical resection for advanced HAE. A 58-year-old female visited the outpatient department presented with HAE. Imaging examination revealed extensive invasion of the hilum, bile duct, and several hepatic vessels, as well as left adrenal metastasis. The patient underwent right trisegmentectomy with left hepatic vein reconstruction, auto-transplantation, and adrenalectomy, with intraoperative Doppler demonstrating patent portal flow before abdominal closure. However, emergency thrombectomy and transcatheter thrombolysis were performed due to the abrupt occurrence of portal vein thrombosis 3 h after surgery. Despite intervention, the residual liver volume remained insufficient (approximately 28% of the standard liver volume), leading to progressive liver failure. The patient expired from multiorgan failure 9 days after operation. This case underscores not only the critical balance between radical resection and preservation of residual liver function in the surgical management of complex HAE, but also the imperative need to establish a comprehensive postoperative thromboprophylaxis.

Toxoplasma gondii is an intracellular protozoan parasite capable of causing chronic infection by forming persistent cysts in the brain. Despite its global burden, no approved vaccine exists. Virus-like particle vaccines expressing microneme protein 8 (MIC8) or apical membrane antigen 1 (AMA1) of T. gondii have previously shown efficacy. In this study, we generated recombinant vaccinia viruses (rVVs) expressing MIC8 and AMA1 and evaluated their efficacy against T. gondii ME49 infection. BALB/c mice were intramuscularly immunized with a combination of MIC8 and AMA1 rVVs and challenged orally with T. gondii ME49. Immunization with MIC8+AMA1 rVVs produced a significant increase in T. gondii-specific IgG. Splenocyte analysis revealed robust activation of CD4+ and CD8+ T cells, as well as expansion of memory B cells. The immunized group exhibited an 89.6% reduction in brain cyst count, with significantly improved survival compared to the control group. These findings demonstrate that combining the antigens MIC8 and AMA1 using a vaccinia virus platform can effectively promote both humoral and cellular immunity, supporting its potential as a vaccine strategy against T. gondii ME49.

Caryophyllaeus brachycollis mainly parasitizes the intestines of globally distributed freshwater fishes, and infection causes significant economic losses to the aquaculture industry. However, data on the molecular epidemiology, population genetics, and systematics of C. brachycollis are scarce. In this study, we sequenced the complete mitogenome of C. brachycollis isolated from Beijing, China. This circular mitogenome comprised 14,273 bp, which was 231 bp shorter than that of C. brachycollis isolated from Wuhan, China. The mitogenome contained 12 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and 2 noncoding regions. Bayesian inference revealed that C. brachycollis belonged to the family Caryophyllaeidae. The taxonomic status of C. brachycollis is controversial when based solely on morphological features. A comparative analysis of the mitogenome sequence obtained in this study revealed novel molecular markers for the accurate ascertainment of the phylogenetic position of this parasite.

The leopard cat (Prionailurus bengalensis) is a wild felid species that serves as a reservoir of zoonotic parasites. In this study, we investigated intestinal parasite taxa by reanalyzing previously published shotgun metagenomic sequencing data from fecal samples of wild leopard cats using a custom 18S rRNA gene reference database constructed from the NCBI nucleotide database. Among 11 metagenomic samples, 5 parasite species were identified: Toxoplasma gondii, Clonorchis sinensis, Strongyloides planiceps, Cylicospirura petrowi, and Pharyngostomum cordatum. These findings demonstrate that shotgun metagenomic analysis of fecal samples can be a useful tool for monitoring zoonotic parasite infections in this species and for investigating parasite life cycles. However, this approach is limited by its dependence on existing reference databases and requires experimental validation of the findings.

We present a nearly complete mitochondrial genome (mitogenome) of Hymenolepis diminuta from a Danish isolate, which was reassembled and comprehensively annotated using whole-genome sequencing data retrieved from the Sequence Read Archive (accession No. ERS056110). Although 2 mitogenomes of H. diminuta have previously been submitted to GenBank (accession No. AP017664, Danish isolate; NC_002767, putative German laboratory strain), the former lacks noncoding regions, while the latter harbors relatively short repeat units. Our newly reconstructed mitogenome is 14,090 bp long, comprising 12 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and a 643-bp noncoding region containing 7 tandem repeat units. The annotated sequence has been deposited in the Third Party Annotation database in GenBank (accession No. BK071817). Phylogenetic analysis based on mitogenomic sequences confirmed a close relationship between H. diminuta and Hymenolepis nana. This improved mitogenome sequence represents a valuable resource for comparative mitogenomic and phylogenetic investigations within the families Hymenolepididae, Taeniidae, and Diphyllobothriidae.

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.