| Hee-Il Lee | 11 Articles |
We developed a new concentration kit, called the ParaEgg (PE), for easy detection trematode eggs from fecal samples in endemic areas of clonorchiasis and metagonimiasis in Korea. To create a standard of detection efficiency, 120 fecal samples were examined using the water–ether concentration method (WECM). The PE kit and Mini ParaSep (PS) kit were used to compare the detection sensitivity of 100 egg-positive and 20 egg-negative samples in WECM. Additionally, stool samples, which were intentionally spiked with 10, 20, and 30 Clonorchis sinensis eggs, were evaluated to assess the sensitivity in lowinfection cases. The PE and PS kits showed detection rates of 100% and 92%, respectively, from 100 egg-positive samples in WECM. Meanwhile, eggs were detected in 3 (PE) and 2 (PS) out of 20 egg-negative samples in WECM. The PE kit detected the highest number of eggs per gram of feces (727 on average), followed by the WECM (524) and PS kit (432). In fecal samples that were intentionally spiked with 10, 20, and 30 C. sinensis eggs, PE only detected eggs 2 out of 5 samples in 10 eggs spiked (40%), and the detection rates were 80% and 100%, respectively. The PE kit enabled a more accurate identification of trematode eggs because of the clearance of small fecal debris in the microscopic field. In conclusion, the PE kit is obviously helpful to detect and identify trematode eggs in stool examinations especially in endemic areas of clonorchiasis and metagonimiasis.
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Human babesiosis is a tick-borne disease induced by the genus Babesia and has been significantly reported in the Republic of Korea. This report shows the cases of 2 patients with human babesiosis who traveled to the USA in 2019. The 2 patients experienced fever and had travel histories to babesiosis-endemic regions. The diagnoses of both cases were verified by the identification of Babesia-infected red blood cells on blood smears. One patient was found to be infected with Babesia microti using polymerase chain reaction (PCR) for 18S rRNA, which discovered the phylogenetic link to the B. microti strain endemic in the USA. The 2 patients recovered from fever with subsequent hemoparasite clearance. Babesiosis could be diagnosed in anyone with histories of travel to babesiosis-endemic countries and tick bites. Furthermore, Babesia-specific PCR is required for determining geno-and phenotypic characteristics.
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This study aimed to evaluate the positive rates for Enterobius vermicularis eggs among preschool children in Yeosu-si, Jeollanam-do, the Republic of Korea (Korea) over a period of 5 years (2017-2021). Perianal swab samples, obtained using cellotape, from 10,392 preschool children in 26 districts were examined microscopically for E. vermicularis eggs. The test results were notified through the local health center, and the families of children who tested positive were advised to provide them anthelmintics treatment. The annual positive rates were 5.0%, 5.2%, 4.4%, 2.2%, and 1.0% in 2017, 2018, 2019, 2020, and 2021, respectively. The overall positive rate was higher in boys than in girls (P< 0.05), and children aged 5-7 years were at a higher risk of being infected than those aged 0-4 years (P< 0.05). Although the rates of infection by E. vermicularis in the survey area, Yeosu-si, were still in the 1% range , the results of this study suggest that they can be significantly reduced through continuous intervention centered around the test–treatment strategy.
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Inflammatory bowel disease (IBD) is a chronic and recurrent illness of the gastrointestinal tract. Treatment of IBD traditionally involves the use of aminosalicylic acid and steroids, while these drugs has been associated with untoward effects and refractoriness. The absence of effective treatment regimen against IBD has led to the exploration of new targets. Parasites are promising as an alternative therapy for IBD. Recent studies have highlighted the use of parasite-derived substances, such as excretory secretory products, extracellular vesicles (EVs), and exosomes, for the treatment of IBD. In this report, we examined whether EVs secreted by Giardia lamblia could prevent colitis in a mouse model. G. lamblia EVs (GlEVs) were prepared from in vitro cultures of Giardia trophozoites. Clinical signs, microscopic colon tissue inflammation, and cytokine expression levels were detected to assess the effect of GlEV treatment on dextran sulfate sodium (DSS)-induced experimental murine colitis. The administration of GlEVs prior to DSS challenge reduced the expression levels of pro-inflammatory cytokines, including tumor necrosis factor alpha, interleukin 1 beta, and interferon gamma. Our results indicate that GlEV can exert preventive effects and possess therapeutic properties against DSS-induced colitis.
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The positive rate of Clonorchis sinensis is the highest among intestinal parasites in the Republic of Korea (Korea). More than 1.2 million people were at risk of C. sinensis infection in Korea in 2012. An intensive control program is being implemented for residents of the 5 major river basins to reduce helminthic infections, including C. sinensis infection. This study evaluated the continuous intensive control program for parasitic diseases including clonorchiasis in areas near the 5 major river basins in Korea over the past 10 years (2011-2020). A total of 335,020 fecal samples (one sample per resident) prepared by the modified sedimentation technic were microscopically examined. Those who expelled helminth eggs were treated with anthelmintics through local health centers and re-examined 3 months later. The overall positive rate of helminths egg was 7.1%. The annual positive rates were dramatically decreased from 14.4% (2011) to 5.9% (2020). The egg positive rate was highest in C. sinensis (5.3%), followed by heterophyid flukes (1.5%) and Trichuris trichiura (0.2%). The prevalence of C. sinensis was significantly higher in males (7.6%) than in females (3.7%), and the highest in the 50–59 years (7.0%) age group. Our results are beneficial to establish prevention and control policies against helminthiases including clonorchiasis in endemic areas in this country.
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Mosquitoes are globally distributed and important vectors for the transmission of many human diseases. Mosquito control is a difficult task and the cost of preventing mosquito-borne diseases is much lower than that for curing the associated diseases. Thus, chemical control remains the most effective tool for mosquito. Due to the long-term intensive use of insecticides to control mosquito vectors, resistance to most chemical insecticides has been reported. This study aimed to investigate the relationship between insecticide resistance and target site mutation of L1014 kdr and G119 ace alleles in 5 species/species group of mosquitoes (Aedes vexans, Ae. albopictus, Anopheles spp., Culex pipiens complex, and Cx. tritaeniorhynchus) obtained from 6 collection sites. For Anopheles spp., the proportion of mosquitoes with mutated alleles in L1014 was 88.4%, homozygous resistant genotypes were observed in 46.7%, and heterozygous resistant genotypes were observed in 41.8%. For the Cx. pipiens complex and Cx. tritaeniorhynchus species, homozygous resistant genotypes were found in 25.9% and 9.8%, respectively. However, target site mutation of L1014 in the Ae. vexans nipponii and Ae. albopictus species was not observed. Anopheles spp., Cx. pipiens complex, and Cx. tritaeniorhynchus mosquitoes were resistant to deltamethrin and chlorpyriphos, whereas Ae. vexans nipponii and Ae. albopictus were clearly susceptible. We also found a correlation between the resistance phenotype and the presence of the L1014 kdr and G119 ace mutations only in the Anopheles spp. population. In this study, we suggest that insecticide resistance poses a growing threat and resistance management must be integrated into all mosquito control programs.
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A survey of mosquitoes, including the vector status of Citations Citations to this article as recorded by
In order to study the range of flight and feeding activity of Citations Citations to this article as recorded by
Field trials evaluating selected commercially available mosquito traps variously baited with light, carbon dioxide, and/or octenol were conducted from 18-27 September 2000 in a malarious area near Paekyeon-ri (Tongil-Chon ) and Camp Greaves in Paju County, Kyonggi Province, Republic of Korea. The host-seeking activity for common mosquito species, including the primary vector of Japanese encephalitis, Citations Citations to this article as recorded by
To evaluate the factors that determine the transmission level of vivax malaria using vectorial capacity, entomological surveys were conducted from June to August, 2000. From 6 nights of human-bait collection in Paju, the human biting rate (ma) was counted as 87.5 bites/man/night. The parity of Citations Citations to this article as recorded by
Until now, 3 Metagonimus spp. (M. yokogawai, M. takahashii, and M. miyatai) causing human metagonimiasis have been reported in Korea. In this study, we investigated the possible presence of Metagonimus spp. other than these 3 species using human fecal samples from an endemic area in Korea. DNA was extracted from Metagonimus egg-positive fecal samples collected from residents of Gurye-gun, Jeollanam-do. A total of 21 representative mitochondrial cytochrome c oxidase subunit I sequences were obtained by PCR and cloning, and sequencing. Phylogenetic analysis revealed 1 cluster corresponding to M. yokogawai (n=10) and 2 additional distinct clusters corresponding to M. kogai (n=8) and M. saitoi (n=3), which were proposed as new species in Japan in 2022. Pairwise cytochrome c oxidase subunit I distances were low for M. yokogawai and M. kogai (mean Kimura 2-parameter: 0.005–0.006), whereas M. saitoi showed higher Korea–Japan values (~0.029), a pattern consistent with geographic structuring. In conclusion, we provide the first molecular evidence for the occurrence of M. kogai and M. saitoi in human fecal samples in Korea. Further confirmation using adult morphology, additional nuclear markers, and ecological surveys are needed to clarify metagonimiasis transmission in the Seomjin-gang (river) basin.
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