Parasites, hosts and diseases最新文献

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.

Sickle cell disease (SCD), a genetic hemoglobin disorder, is a major public health challenge in sub-Saharan Africa, particularly in Tanzania, due to its association with high morbidity and mortality from infections. The disease is the leading cause of complications, emphasizing the urgent need for effective preventive strategies and diagnostic protocols. We evaluated the implementation and effectiveness of infection prevention measures and laboratory diagnostic compliance at Nyamagana District Hospital, emphasizing their effects on patient outcomes and survival rates. This retrospective observational study analyzed the medical records of 157 patients with SCD admitted to Nyamagana District Hospital for infection treatment between January 2022 and 2024. The infection profiles, utilization of preventive interventions (recommended drugs, vaccinations, and chemoprophylaxis), and diagnostic laboratory compliance were assessed. Of the 157 participants, 90.4% had at least one infection during their hospital stay, suggesting the vulnerability of this population to infections. Furthermore, malaria emerged as the most prevalent type of infection (40.1%), which is consistent with its endemic status in Tanzania. Other significant infections included unspecified diarrhea (12.5%) and upper respiratory tract infections (10.8%). Despite the high coverage rates of penicillin V prophylaxis (72%) and pneumococcal vaccination (100%), the utilization of malaria chemoprophylaxis and hydroxyurea was low (only 10.8% and 16.6%, respectively). The diagnostic laboratory test compliance, essential for accurate infection management, was moderate at 63.1%, with significant deficiencies in the blood, urine, and stool cultures and antibiotic susceptibility testing. The administration of hydroxyurea significantly reduced malaria prevalence (P=0.005), fewer vaso-occlusive crises (P<0.001), and severe anemia incidence (P=0.034). Thus, enhancing access to preventive measures and improving diagnostic laboratory compliance are crucial steps for reducing infection-related complications among patients with SCD in Nyamagana.

The alveolate protozoan parasite Perkinsus olseni infects a range of marine bivalves inhabiting tidal flats and shallow subtidal zones, causing considerable damage to shellfish industries. Infection by P. olseni is typically assessed using Ray's fluid thioglycollate medium (RFTM) assay, with gill tissue often employed as a diagnostic proxy for whole-body infection. However, the diagnostic reliability of gill-based assays across diverse ecological settings-particularly under low-infection conditions-remains uncertain. In this study, we investigated tissue-specific distribution and the diagnostic performance of the RFTM assay in detecting P. olseni in Manila clams (Ruditapes philippinarum) collected from 6 tidal flats along Korea's west and south coast. The assay was applied to 6 different tissues, including gills and visceral mass. Infection prevalence reached 100% at most sites, except at Padori (90%). Whole-body infection intensity ranged from 0.1×104 to 3.7×106 cells per gram of tissue. The visceral mass consistently harbored the largest proportion of parasites (27.8%-49.0%), followed by the mantle (17.4%-30.6%) and gills (19.4%-25.2%). Gill infection levels correlated strongly with whole-body infection intensity (r²=0.6-0.95), supporting their diagnostic value in high-infection areas. However, at Padori-where infection levels were lowest-the efficacy of the gill assay dropped to 56%, resulting in a 44% false negative rate. These results underscore the limitations of relying solely on gill tissue in low-infection environments and highlight the need for a context-dependent diagnostic approach. A dual-tissue strategy incorporating both gill and whole-body samples is recommended to improve diagnostic accuracy in P. olseni surveillance of Manila clam populations.

The incidence of immune system diseases is increasing globally, particularly in developed countries. The hygiene and old friend hypotheses suggest that the decreased incidence of helminth infections in these countries may underlie the rising prevalence of autoimmune, allergic, and inflammatory diseases. The preventive and therapeutic potential of Trichinella spiralis, a helminthic parasite, has been well demonstrated in animal models of immune dysregulation-mediated diseases. This review comprehensively analyze how T. spiralis modulates immune responses across a spectrum of immune dysregulation. We systematically review the key research findings on the effects of T. spiralis infection on immune-related disease. T. spiralis has shown the ability to regulate host immune responses in autoimmune, allergic, and inflammatory disorders, exerting anti-inflammatory effects and restoring immune homeostasis through various immunological pathways. Given its significant immunomodulatory potential, T. spiralis represents a promising candidate for therapeutic interventions against immune-mediated diseases, warranting further molecular investigations and clinical applications.

Stray cats serve as reservoir hosts for various zoonotic parasites, posing a significant risk of transmission to humans. This study aimed to assess the prevalence of parasitic infections in stray cats from Gimpo-si, Gyeonggi-do, Korea. A total of 101 fecal and 237 blood (serum) samples were collected from 237 stray cats captured through the trapneuter-return program in 2021. The samples were analyzed using microscopy, nested-PCR, and ELISA to detect parasitic infections. Fecal examination revealed that Toxocara cati eggs were present in 26.7% (27/101) of samples, while eggs of Spirometra sp. (2%), Clonorchis sinensis (1%), and Trichuris sp. (1%) were also detected. PCR analysis identified Toxoplasma gondii DNA in 17 (16.8%) fecal samples, while genetic markers of Cryptosporidium felis and Enterocytozoon bieneusi were each detected in 4 (4%) samples. Positive rates of IgM and IgG were 21.9% (52/237) and 21.1% (50/237) in serological tests for T. gondii-specific antibodies. This study confirms the widespread presence of zoonotic parasites in stray cats from Gimpo-si, highlighting the potential public health risks associated with these infections. Continuous surveillance and control measures are essential from a One Health perspective to reduce the risk of zoonotic transmission.

Amoebic enteritis is often misdiagnosed or overlooked due to its nonspecific clinical presentation. This study presents a comprehensive clinicopathological analysis of 14 confirmed cases of amoebic enteritis, examining their clinical manifestations, histopathological features, and responses to treatment. Periodic acid-Schiff and hexamine silver stains were employed to aid in diagnosis. A review of the relevant literature is also included to improve recognition and diagnostic accuracy of this uncommon but clinically significant condition.

The continuous Plasmodium falciparum kelch13 (PfK13) genetic alterations conferring resistance to artemisinin-based combination therapies and partner drugs pose a significant threat to effective treatment and control of P. falciparum infection in developing countries. This review evaluates the emergence and epidemiology of the PfK13 mutation associated with artemisinin resistance in the sub-Saharan Africa (SSA) population. Despite empirical control and artemisinin combination therapy, the PfK13 gene mutation, previously described in Southeast Asia, has been reported in the SSA. Eight of these validated markers, including P553L, M476I, C580Y, A675V, P574L, R561H, R622I, and F446I, were reported among the SSA population. Novel and unvalidated markers, such as P615S, M472I, F434S, A578S, P570L, Y558C, K563R, A569T, I684N, M472I, and C473F spread among the population with low frequency. We provide insight into the emergence and spread of validated and unvalidated PfK13 mutations among the SSA population, which could lead to high artemisinin resistance. Investigating the verified PfK13 mutations will improve prophylactic strategies, prognostic diagnosis and guide effective population-based surveillance for effective P. falciparum malaria control in SSA.