Parasites, hosts and diseases最新文献

Ticks are important ectoparasites that serve as key vectors of various pathogens, posing significant risks to both human and animal health. In this study, 3 genera and 5 species of ticks, including Haemaphysalis longicornis, H. flava, H. doenitzi, Ixodes nipponensis, and Amblyomma testudinarium, were analyzed both morphologically and molecularly. Morphological identification was conducted using established taxonomic keys, followed by molecular characterization through analysis of complete cytochrome c oxidase subunit 1 (cox1, 1,539 bp) and mitochondrial 16S rDNA (1,191-1,215 bp), and nuclear 18S rDNA (1,812-1,816 bp). Phylogenetic and pairwise distance analyses demonstrated that all 3 genes were effective for genus identification; cox1 and mitochondrial 16S rDNA were more effective than 18S rDNA in species identification. Additionally, this study is the first to identify H. doenitzi in the Korean mainland via molecular characterization. These results may serve as reference data for the molecular identification of tick species.

Trichomonads are flagellated protozoa that have occasionally been detected in the human respiratory tract, although detection rates have often been underestimated. We applied a nested PCR assay targeting the 18S rRNA gene of trichomonads to induced sputum from asthma patients to determine the prevalence of Trichomonas. Induced sputum was collected from 41 adults with asthma and analyzed through nested PCR using broad-range trichomonad primers and DNA sequencing for species identification. Nested PCR detected trichomonad DNA in 10 of the 41 (24.4%) samples. Sequencing and phylogenetic analysis revealed Trichomonas tenax in 8 cases and Tetratrichomonas sp. in 2 cases. These findings indicate that trichomonads can be present in the lower airways of patients with asthma, warranting further investigation into their clinical relevance.

Posttranslational modification by the small ubiquitin-related modifier (SUMO) is one of the crucial cellular processes in Giardia lamblia, a protozoan pathogen. In this study, 5 candidate SUMO substrate proteins of G. lamblia trophozoites were chosen based on their enrichment through affinity chromatography using a SUMO-interaction motif: never in mitosis A-related kinase (NEK), aminoacyl-histidine dipeptidase (AHD), protein disulfide isomerase 2 (PDI2), alcohol dehydrogenase 3, and ornithine carbamoyltransferase. Transgenic Giardia trophozoites expressing 1 of the 5 candidate SUMO substrate proteins were constructed, and their expression was confirmed by western blot using hemagglutinin-tag. Arginine deiminase (ADI) protein was expressed in Giardia trophozoites as a positive control. Cell extracts were processed for affinity chromatography using SUMO-interaction motif resin. As expected, the SUMOylated form of ADI was detected in the affinity chromatography extracts of ADI-expressing cells. Among the 5 candidate proteins, SUMOylated forms of NEK, AHD, and PDI2 were identified in the affinity chromatography extracts. These results suggest that NEK, AHD, and PDI2 activity is modulated via SUMOylation in Giardia trophozoites.

Baseline genetic characterization of malaria vector populations provides critical data for evidence-based surveillance in persistent transmission foci. This pilot study generated preliminary genetic baseline data for Anopheles populations in the Menoreh Hills border region between Central Java and Yogyakarta provinces, Indonesia, addressing a key geographic gap in regional vector research. Adult female mosquitoes were collected from 3 houses with reported malaria cases in Ngadirejo Village using standardized entomological methods, including human landing, animal landing, and resting collections. Specimens were morphologically identified and molecularly characterized via ITS2 gene sequencing. Phylogenetic analyses were assessed using maximum likelihood methods, and genetic diversity indices were calculated to examine population structure. A total of 62 specimens representing 3 species were collected exclusively through animal landing collections: Anopheles vagus (48 specimens, 77.4%), Anopheles maculatus (9 specimens, 14.5%), and Anopheles kochi (5 specimens, 8.1%). An. kochi exhibited high haplotype diversity (Hd=0.709) with low nucleotide diversity (π=0.004), while An. maculatus showed lower haplotype diversity (Hd=0.480) and higher nucleotide diversity (π=0.026). Phylogenetic analysis revealed Purworejo specimens clustered with regional populations: An. kochi grouped within Clade I with Indonesian isolates; An. maculatus distributed across multiple clades; An. vagus formed a cohesive unit with other Indonesian populations. The exclusive success of animal landing collections in the Menoreh Hills highlands provides key methodological insights. This study offers essential baseline reference data, validates cost-effective genetic surveillance approaches, and supports future large-scale population connectivity studies across the Menoreh Hills malaria transmission complex.

Fasciola hepatica is a species of zoonotic liver flukes with a broad range of definitive hosts worldwide. However, this liver fluke has not been detected in Korean water deer (Hydropotes inermis argyropus). This study provides the first evidence for Korean water deer being a definitive host of F. hepatica.

Enterocytozoon is a genus of microsporidian parasites, with Enterocytozoon bieneusi being a well-known species. It infects various mammalian hosts, including humans, and exhibits zoonotic potential. Out of the 97 fecal and intestinal samples collected from wild raccoon dogs in Korea, 12 (12.4%) tested positive for E. bieneusi via PCR, revealing 2 genotypes: genotype D and EbpA. Both genotypes were found to belong to the zoonotic Group 1. Notably, this study is the first to report the EbpA genotype in Korea. Although studies on E. bieneusi in raccoon dogs are relatively limited, the findings suggest potential public health concerns.

Toxoplasma gondii is a neurotropic apicomplexan protozoan estimated to affect approximately 30% of the global population. In this review, we aimed to examine scientific evidence on the potential role of T. gondii infection in the development of autism spectrum disorder (ASD), a heterogeneous neurodevelopmental disorder. This review summarizes the current literature exploring the possible association between T. gondii and ASD. Findings indicate that toxoplasmosis may contribute to host alterations, including the induction of humoral and cellular immune responses, production of various cytokines, and changes in neurotransmitter levels (e.g., serotonin, dopamine, acetylcholine, gamma-aminobutyric acid, and glutamate), as well as the activation of enzymes such as indoleamine 2,3-dioxygenase, which may influence the pathophysiology of ASD. In conclusion, this review suggests that T. gondii infection could act as a potential risk factor for ASD. However, further intensive studies are necessary to clarify the role of this parasite in the etiology and progression of ASD. This review is anticipated to stimulate further studies aimed at understanding and potentially reducing the burden of neurodevelopmental disorders worldwide.

Clonorchis sinensis is a liver fluke that causes clonorchiasis, a significant public health concern in East Asia, closely associated with hepatobiliary diseases. Dopamine is an essential neurotransmitter involved in neuromuscular signaling, and its uptake by trematodes may contribute to parasite physiology and survival. This study aimed to characterize the dopamine transporter CsDAT in C. sinensis by synthesizing cDNA from adult worms and expressing it in Xenopus laevis oocytes; subsequently, uptake assays were conducted using radiolabeled dopamine. Functional assays confirmed that CsDAT mediates dopamine uptake in a sodium-dependent manner. The uptake was saturable and exhibited Michaelis-Menten kinetics with a Michaelis constant of 454.5 nM and a maximum uptake rate of 1,422.5 fmol/oocyte/h. CsDAT efficiently transported dopamine with high affinity, indicating its physiological relevance in the parasite. A 3-dimensional model of CsDAT was constructed to examine its structural features. The predicted structure contained a conserved substrate-binding pocket similar to that of other known neurotransmitter transporters. Molecular docking simulations showed that dopamine stably fits within the binding pocket. The key amino acid residues formed hydrogen bonds and hydrophobic interactions with dopamine. Interestingly, dopamine and several inhibitors demonstrated higher binding affinity to CsDAT than the human dopamine transporter. This study provides the first functional and structural insights into CsDAT. The higher inhibitor-binding affinity of CsDAT compared to human dopamine transporter suggests its potential for use in therapeutic exploration. Targeting CsDAT may facilitate the development of new therapeutic agents against clonorchiasis with minimal off-target effects on the human nervous system.

Poultry coccidiosis, caused by 7 Eimeria species, has a significant economic impact on the poultry industry and is managed mainly by chemotherapeutic drugs. However, alternative control measures are needed due to the emergence of drug-resistant strains. This study aimed to evaluate the anticoccidial effects of a multicomplex mineral-based diet in broilers infected with Eimeria acervulina. Broilers were fed a multicomplex mineral-based diet and infected with E. acervulina. Fecal oocyst shedding was 39.0% lower in the E. acervulina-infected broilers treated with the multicomplex mineral compared to that in untreated-infected broilers (365.7×106±45.7 versus 599.8×106±8.7, P<0.05). On day 6 post-infection, body weight gain was significantly higher in treated-infected chickens than untreated chickens (103.2±1.5% versus 94.1±1.7%, P<0.001). The lesion scores were similar between the 2 groups. Histopathological observations revealed that the width of the villi in the treated-infected chickens (286±9.5 μm) was significantly increased by 19.1% (240±10.8 μm, P<0.05) and 34.9% (212±7.3 μm, P<0.001) compared to those in the untreated-uninfected and untreated-infected groups, respectively. However, the villous height and crypt depth were similar between the untreated- and treated-infected groups. The positive effects of the dietary multicomplex mineral, including reduced fecal oocyst shedding, increased weight gain, and increased villi width, suggest its potential application in mitigating the adverse effects of Eimeria infection in both conventional and organic chicken industries.

Enterocytozoon bieneusi is an opportunistic microsporidian parasite with zoonotic potential that causes gastrointestinal illness in humans and animals. This study aimed to investigate the presence and genetic diversity of E. bieneusi from cats in Korea and to assess the potential public health risks associated with zoonotic genotypes. Among the 137 feline fecal samples, 4 (2.9%) were PCR-positive for E. bieneusi. In addition, 2 E. bieneusi genotypes were identified: Type IV, a known zoonotic genotype belonging to Group 1, and KCAT1, a novel genotype with zoonotic potential belonging to Group 1. This study is the first to report on these genotypes from cats in Korea, most of which were companion cats visiting veterinary clinics. Despite the low detection rate, the presence of zoonotic genotypes in companion cats is a potential public health concern because of the close physical interaction between cats and their human caregivers. These findings indicate the importance of routine monitoring and the molecular characterization of E. bieneusi in companion animals to comprehensively understand their zoonotic transmission patterns and to guide future risk assessments and preventive strategies.