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.

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.

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.

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.

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.

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.

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.

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.