Korean Journal of Parasitology最新文献

Toxoplasma gondii, an intracellular protozoan parasite that infects one-third of the world's population, has been reported to hijack host cell apoptotic machinery and promote either an anti- or proapoptotic program depending on the parasite virulence and load and the host cell type. However, little is known about the regulation of human FHs 74 small intestinal epithelial cell viability in response to T. gondii infection. Here we show that T. gondii RH strain tachyzoite infection or ESP treatment of FHs 74 Int cells induced apoptosis, mitochondrial dysfunction and ER stress in host cells. Pretreatment with 4-PBA inhibited the expression or activation of key molecules involved in ER stress. In addition, both T. gondii and ESP challenge-induced mitochondrial dysfunction and cell death were dramatically suppressed in 4-PBA pretreated cells. Our study indicates that T. gondii infection induced ER stress in FHs 74 Int cells, which induced mitochondrial dysfunction followed by apoptosis. This may constitute a potential molecular mechanism responsible for the foodborne parasitic disease caused by T. gondii.

Based on the field investigations in 91 investigation sites (counties) in southwest China between 2001 and 2019, the present paper reported the chigger mites on A. agrarius mice in southwest China for the first time by using a series of statistical methods. From 715 striped field mice captured in 28 of 91 investigated sites, only 255 chiggers were collected, and they were identified as 14 species, 6 genera in 3 subfamilies under 2 families. Of 715 A. agrarius mice, only 24 of them were infested with chigger mites with low overall prevalence (PM=3.4%), overall mean abundance (MA=0.36 mites/host) and overall mean intensity (MI=10.63 mites/host). The species diversity and infestation of chiggers on A. agrarius were much lower than those previously reported on some other rodents in southwest China. On a certain species of rodent, A. agrarius mouse in southwest China seems to have a very low susceptibility to chigger infestations than in other geographical regions. Of 14 chigger species, there were 3 dominant species, Leptotrombidium sialkotense, L. rupestre and Schoengastiella novoconfuciana, which were of aggregated distribution among different individuals of A. agrarius hosts. L. sialkotense, one of 6 main vectors of scrub typhus in China, was the first dominant on A. agrarius. The species similarity of chigger mites on male and female hosts was low with CSS=0.25, and this reflects the sex-bias of different genders of A. agrarius mice in harboring different chigger species.

Soil-transmitted helminth (STH) infections are still a considerable challenge in Myanmar. We undertook a control program for STH infections (especially Trichuris trichiura) among schoolchildren in Myanmar using mass drug administration (MDA) and health education. Around 1,700 schoolchildren from 15 primary schools in 3 suburban districts (Shwe Pyi Thar, Twantay, and Kyauktan) of the Yangon Region were subjected in this study during 2017-2019. All of the schoolchildren in each school were orally administered albendazole (400 mg in a single dose) 2, 3, and 4 times a year in 2017, 2018, and 2019, respectively. The results revealed that the egg positive rate of any intestinal helminths (including STH) was reduced from 37.6% (649/1,724) in 2017 to 22.8% (352/1,542) in 2019. The egg positive rate of Ascaris lumbricoides was decreased remarkably from 23.3% (402/1,724) in 2017 to 3.6% (56/1,542) in 2019. However, that of T. trichiura was only slightly reduced from 26.9% (464/1,724) in 2017 to 20.2% (312/1,542) in 2019. The intensity of infection with A. lumbricoides and T. trichiura was both more or less reduced, and the proportion of light infection cases with A. lumbricoides and T. trichiura increased from 35.6% in 2017 to 64.3% in 2019 and from 70.3% in 2017 to 81.7% in 2019, respectively. The results indicated that repeated MDAs (2-4 times a year for 3 years) using albendazole on schoolchildren in Myanmar failed to control T. trichiura infection. For a successful control of trichuriasis in Myanmar, new MDA strategies, using a modified albendazole regimen (multiple daily doses for 2 or 3 days) or an alternative anthelmintic drug, such as oxantel pamoate, is strongly recommended.

In this study, we intended to describe a human case of lumbosacral canal sparganosis in People's Republic of China (China). A 56-year-old man was admitted to Xiangya Hospital Central South University in Changsha, Hunan province, China after having an experience of perianal pain for a week. An enhancing mass, a tumor clinically suggested, was showed at the S1-S2 level of the lumbosacral spine by the examination of magnetic resonance imaging (MRI) with gadolinium contrast. The patient was received the laminectomy from S1 to S2, and an ivory-white living worm was detected in inferior margin of L5. In ELISA-test with cerebrospinal fluid (CSF) and serum samples, anti-sparganum antibodies were detected. He had a ingesting history of undercooked frog meat in his youth. By the present study, a human case of spinal sparganosis invaded in lumbosacral canal at the S1-S2 level was diagnosed in China. Although the surgical removal of larvae is known to be the best way of treatment for sparganosis, we administered the high-dosage of praziquantel, albendazole and dexamethasone to prevent the occurrence of another remain worms in this study.

Enterocytozoon bieneusi is a microsporidian pathogen. Recently, the equestrian population is increasing in Korea. The horse-related zoonotic pathogens, including E. bieneusi, are concerns of public health. A total of 1,200 horse fecal samples were collected from riding centers and breeding farms in Jeju Island and inland areas. Of the fecal samples 15 (1.3%) were PCR positive for E. bieneusi. Interestingly, all positive samples came from Jeju Island. Diarrhea and infection in foals were related. Two genotypes (horse1, horse2) were identified as possible zoonotic groups requiring continuous monitoring.

Macrophages play a key role in chronic inflammation, and are the most abundant immune cells in the tumor microenvironment. We investigated whether an interaction between inflamed prostate cancer cells stimulated with Trichomonas vaginalis and macrophages stimulates the proliferation of the cancer cells. Conditioned medium was prepared from T. vaginalis-infected (TCM) and uninfected (CM) mouse prostate cancer (PCa) cell line (TRAMP-C2 cells). Thereafter conditioned medium was prepared from macrophages (J774A.1 cell line) after incubation with CM (MCM) or TCM (MTCM). When TRAMP-C2 cells were stimulated with T. vaginalis, protein and mRNA levels of CXCL1 and CCL2 increased, and migration of macrophages toward TCM was more extensive than towards CM. Macrophages stimulated with TCM produced higher levels of CCL2, IL-6, TNF-α, their mRNAs than macrophages stimulated with CM. MTCM stimulated the proliferation and invasiveness of TRAMP-C2 cells as well as the expression of cytokine receptors (CCR2, GP130, CXCR2). Importantly, blocking of each cytokine receptors with anti-cytokine receptor antibody significantly reduced the proliferation and invasiveness of TRAMP-C2 cells. We conclude that inflammatory mediators released by TRAMP-C2 cells in response to infection by T. vaginalis stimulate the migration and activation of macrophages and the activated macrophages stimulate the proliferation and invasiveness of the TRAMP-C2 cells via cytokine-cytokine receptor binding. Our results therefore suggested that macrophages contribute to the exacerbation of PCa due to inflammation of prostate cancer cells reacted with T. vaginalis.

Our objective was to investigate whether inflammatory microenvironment induced by Trichomonas vaginalis infection can stimulate proliferation of prostate cancer (PCa) cells in vitro and in vivo mouse experiments. The production of CXCL1 and CCL2 increased when cells of the mouse PCa cells (TRAMP-C2 cell line) were infected with live T. vaginalis. T. vaginalis-conditioned medium (TCM) prepared from co-culture of PCa cells and T. vaginalis increased PCa cells migration, proliferation and invasion. The cytokine receptors (CXCR2, CCR2, gp130) were expressed higher on the PCa cells treated with TCM. Pretreatment of PCa cells with antibodies to these cytokine receptors significantly reduced the proliferation, mobility and invasiveness of PCa cells, indicating that TCM has its effect through cytokine-cytokine receptor signaling. In C57BL/6 mice, the prostates injected with T. vaginalis mixed PCa cells were larger than those injected with PCa cells alone after 4 weeks. Expression of epithelial-mesenchymal transition markers and cyclin D1 in the prostate tissue injected with T. vaginalis mixed PCa cells increased than those of PCa cells alone. Collectively, it was suggested that inflammatory reactions by T. vaginalis-stimulated PCa cells increase the proliferation and invasion of PCa cells through cytokine-cytokine receptor signaling pathways.

Toxoplasma gondii ME49 infections are typically diagnosed by serological tests. However, serological diagnosis of RH strain-induced toxoplasmosis remains unknown. In order to develop seradiagnosis of above 2 kinds of infections, we generated recombinant virus-like particles (VLPs) displaying the T. gondii rhoptry protein 4 (ROP4) and evaluated their potential in T. gondii ME49 or RH strain infection diagnostics. Mice were orally infected with either the tachyzoites of T. gondii (RH) or cysts of T. gondii (ME49) at various dosages, and sera were collected at regular intervals. ELISA-based serological tests were performed to assess IgG, IgM, and IgA antibody responses against ROP4 VLP antigen and tissue lysate antigen (TLA). Compared to TLA, IgG, IgM, and IgA levels to ROP4 VLP antigen were significantly higher in the sera of T. gondii RH-infected mice 1 and 2 week post-infection (PI). T. gondii-specific IgG antibody was detected at 1, 2, 4, and 8 week PI in the T. gondii ME49-infected mice with infection dose-dependent manner. These results indicated that the ROP4 VLP antigen was highly sensitive antigens detecting T. gondii RH and ME49 antibodies at an early stage.

This study was done to provide an analytical overview on the latest malaria infection clusters by evaluating temporal trends during 2010-2019 in Korea. Incheon was the most likely cluster (MLC) for all cases of malaria during the total period. MLCs for P. falciparum, vivax, malariae, ovale, and clinically diagnosed malaria without parasitological confirmation were Jeollanam-do, Incheon, Gangwon-do, Gyeongsangnam-do, and Jeollabuk-do, respectively. Malaria was decreasing in most significant clusters, but Gwangju showed an increase for all cases of malaria, P. vivax and clinically diagnosed cases. Malaria overall, P. falciparum and P. vivax seem to be under control thanks to aggressive health measures. This study might provide a sound scientific basis for future control measures against malaria in Korea.

Total 513 heterophyid flukes were collected from a carcass of wild Korean raccoon dog, Nyctereutes procyonoides koreensis, in Korea. With morphological and molecular characteristics, the flukes were identified to Cryptocotyle lata. The adult C. lata were minute, transparent, pentagonal, 522 µm long by 425 µm wide. Ceca extended into post-testicular region. Ventrogenital sac elliptical, 79 µm by 87 µm with genital pore and ventral sucker. Two testes semielliptical and slightly lobed, located in the posterior region, right testis 173 µm by 155 µm, left testis 130 µm by 134 µm. In a phylogenetic tree, the fluke specimen of this study was grouped with C. lata divergent from Cryptocotyle lingua. We report here N. procyonoides koreensis first as a natural definitive host of C. lata.