Publications by authors named "Shin-Hyeong Cho"

135 Publications

Molecular evidence of zoonotic Babesia species, other than B. microti, in ixodid ticks collected from small mammals in the Republic of Korea.

Vet Med Sci 2021 Sep 7. Epub 2021 Sep 7.

Division of Vectors and Parasitic Disease, Korea Disease Control and Prevention Agency, Cheongju-Si, Chungcheongbuk-Do, the Republic of Korea.

The occurrence of tick-borne infectious diseases, including zoonotic babesiosis, has become a serious concern in recent years. In this study, we detected Babesia spp. using polymerase chain reaction (PCR) amplification of the 18S rRNA of the parasites isolated from ixodid ticks collected from small mammals in the Republic of Korea (ROK). Sequence analysis of the PCR amplicon revealed the presence of B. duncani, B. venatorum, B. capreoli/divergens, and, the most prevalent, B. microti in the ticks. The molecular phylogenetic analysis showed that the four species-specific18S rRNA sequences clustered in four distinct clades. This is the first study to provide molecular evidence for the presence of zoonotic Babesia spp. other than B. microti in ticks in the ROK.
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http://dx.doi.org/10.1002/vms3.581DOI Listing
September 2021

Survey of Zoonotic Trematode Metacercariae in Fish from Irrigation Canal of Togyo-jeosuji (Reservoir) in Cheorwon-gun, Gangwon-do, Republic of Korea.

Korean J Parasitol 2021 Aug 18;59(4):427-432. Epub 2021 Aug 18.

Research Center for Fish Environmental Institute/ Wildlife and Fish Research & Conservation Center, Kangwon National University, Chuncheon 24341, Korea.

The infection status of zoonotic trematode metacercariae (ZTM) was investigated in total 568 freshwater fishes (19 species) from the irrigation canal of Togyo-jeosuji (Reservoir) in Cheorwon-gun, Gangwon-do, the Republic of Korea for 3 years (2018-2020). All fishes were examined using the artificial digestion method. The metacercariae of Clonorchis sinensis (CsMc) were detected in 180 (43.8%) out of 411 fish of positive species, and their infection intensity was 38 per fish infected (PFI). Especially, in 2 fish species, i.e., Pseudorasbora parva and Puntungia herzi, the prevalence was 82.1% and 31.3%, and the infection intensity with CsMc was 88 and 290 PFI, respectively. Metagonimus spp. metacercariae (MsMc) were found in 403 (74.1%) out of 544 fish of positive species, and their infection intensity was 62 PFI. In the pale chub, Zacco platypus, the prevalence of MsMc was 98.6%, and their infection intensity was 144 PFI. Centrocestus armatus metacercariae were detected in 171 (38.9%) out of 440 fish of positive species, and their infection intensity was 1,844 PFI. Echinostoma spp. metacercariae were found in 94 (19.6%) out of 479 fish of positive species, and their infection intensity was 3 PFI. Metorchis orientalis metacercariae were detected in 43 (29.3%) out of 147 fish of positive species, and their infection intensity was 4 PFI. By the present study, it has been confirmed that some species of ZTM, including CsMc and MsMc, are prevalent in fishes from the irrigation canal of Togyo-jeosuji in Cheorwon-gun, Gangwon-do, Korea.
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http://dx.doi.org/10.3347/kjp.2021.59.4.427DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8413859PMC
August 2021

Prevalence and Infection Intensity of Zoonotic Trematode Metacercariae in Fish from Soyang-cheon (Stream), in Wanju-gun, Jeollabuk-do, Korea.

Korean J Parasitol 2021 Jun 21;59(3):265-271. Epub 2021 Jun 21.

Division of Microorganism, Jeollabuk-do Institute of Health and Environment, Imsil 55928, Korea.

We surveyed on the infection status of zoonotic trematode metacercariae (ZTM) in freshwater fishes from Soyang-cheon (a branch stream of Mangyeong-gang) in Wanju-gun, Jeollabuk-do, the Republic of Korea. A total of 927 fishes were individually examined with the artificial digestion method during 2013-2015 (462 fish in 15 spp.) and 2018-2019 (465 fish in 25 spp.). Clonorchis sinensis metacercariae were detected in 207 (31.4%) out of 659 fishes in 14 positive fish species (PFS), and their mean intensity was 114 per fish infected (PFI). Metagonimus spp. metacercariae were found in 302 (37.4%) out of 808 fishes in 21 PFS, and their mean intensity was 12 PFI. Centrocestus armatus metacercariae were detected in 222 (59.0%) out of 376 fishes in 12 PFS, and their mean intensity was 383 PFI. Echinostoma spp. metacercariae were found in 139 (22.1%) out of 628 fishes in 10 PFS, and their mean intensity was 7 PFI. Clinostomum complanatum metacercariae were detected in 14 (6.5%) out of 214 fishes in 4 PFS, and their mean intensity was 2.4 PFI. Metorchis orientalis metacercariae were detected in 36 (13.5%) out of 267 fishes in 5 PFS, and their mean intensity was 4.3 PFI. Conclusively, the prevalence and infection intensity of ZTM is generally not so high in fishes from Soyang-cheon. However, those of C. sinensis metacercariae are more or less higher in 2 fish species, Pungtungia herzi and Sarcocheilichthys variegatus wakiyae.
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http://dx.doi.org/10.3347/kjp.2021.59.3.265DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8255493PMC
June 2021

High Endemicity with Clonorchis sinensis Metacercariae in Fish from Yongjeon-cheon (Stream) in Cheongsong-gun, Gyeongsangbuk-do, Korea.

Korean J Parasitol 2021 Feb 19;59(1):97-101. Epub 2021 Feb 19.

Infectious Disease Research Division, Gyeongsangbuk-do Government Public Institue of Health and Environment, Yeongcheon 38874, Korea.

The infection status with Clonorchis sinensis metacercariae (CsMc) was examined in freshwater fishes from Yongjeon-cheon (a branch of Nakdong-gang) located in Cheongsong-gun, Gyeongsangbuk-do, the Republic of Korea (Korea). A total of 750 fishes in 19 species were examined by the artificial digestion method for 2 years (2019 and 2020). CsMc were detected in 378 (51.4%) out of 735 fishes in 14 species (73.7%), and the infection intensity was 666 per fish infected. In 2019, CsMc were found in 172 (68.0%) out of 253 fishes in 10 species, and the infection intensity was 565 per fish infected. In 2020, CsMc were detected in 206 (62.2%) out of 331 fishes in 10 species, and the infection intensity was 751 per fish infected. The other zoonotic trematode, ie. Metagonimus spp., Centrocestus armatus, Echinostoma spp. and Clinostomum complanatum, metacercariae were also detected in fishes from the survey streams, but their endemicities were relatively low. Conclusively, it was first confirmed that CsMc are highly endemic in fishes from Yongjeon-cheon in Cheongsong-gun, Gyeongsangbuk-do, Korea.
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http://dx.doi.org/10.3347/kjp.2021.59.1.97DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7939965PMC
February 2021

Survey of Zoonotic Trematode Metacercariae in Fish from Water Systems of Geum-gang (River) in Republic of Korea.

Korean J Parasitol 2021 Feb 19;59(1):23-33. Epub 2021 Feb 19.

Division of Microbiology, Chungcheongnam-do Institute of Health and Environment, Hongseong 32254, Korea.

The infection status of zoonotic trematode metacercariae (ZTM) was surveyed in freshwater fishes from the water systems of Geum-gang (River) in the Republic of Korea (Korea). A total of 1,161 freshwater fishes from 6 local sites of Geum-gang were examined with the artificial digestion method for 4 years (2012-2015). Clonorchis sinensis metacercariae were detected in 122 (37.2%) out of 328 fishes in the positive fish species from 4 surveyed areas, and their mean intensity was 43 per fish infected. Metagonimus spp. metacercariae were found in 432 (51.7%) out of 835 fishes in the positive fish species from all 6 surveyed areas, and their mean intensity was 30 per fish infected. Centrocestus armatus metacercariae were detected in 285 (75.0%) out of 380 fishes in the positive fish species from 6 surveyed areas, and their mean intensity was 2,100 per fish infected. Echinostoma spp. metacercariae were found in 56 (19.7%) out of 284 fishes in the positive fish species from 5 surveyed areas, and their mean intensity was 10 per fish infected. Clinostomum complanatum metacercariae were detected in 98 (57.3%) out of 171 fishes in the positive fish species from only 2 surveyed areas, and their mean intensity was 11 per fish infected. Conclusively, the endemicity of ZTM is not so high in fishes from water systems of Geum-gang in Korea although it is more or less different by fish species, surveyed areas and ZTM species.
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http://dx.doi.org/10.3347/kjp.2021.59.1.23DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7939959PMC
February 2021

Risk Factors of Clonorchis sinensis Human Infections in Endemic Areas, Haman-Gun, Republic of Korea: A Case-Control Study.

Korean J Parasitol 2020 Dec 29;58(6):647-652. Epub 2020 Dec 29.

Division of Vectors and Parasitic Diseases, Korea Disease Control and Prevention Agency, Cheongju 28159, Korea.

Clonorchis sinensis is the most common fish-borne intestinal parasite in Korea. The aim of the present investigation was to survey the status of C. sinensis infection and analyze associated risk factors in residents of Haman-gun, Gyeongsangnam-do. A total of 5,114 residents from 10 administrative towns/villages voluntarily agreed to participate in the study, which comprised fecal examination, a questionnaire survey for risk factors, ultrasonography, and enzymelinked immunosorbent assay for cancer biomarker detection in the blood. We detected C. sinensis eggs in 5.3% of the subjects. By region, Gunbuk-myeon had the highest number of residents with C. sinensis eggs. The infection rate and intensity were higher in male than in female residents. Based on the risk factor questionnaire, infection was highly associated with drinking, a history of C. sinensis infection, and the practice of eating of raw freshwater fish. Extension of the bile duct, infection intensity, and cancer biomarker detection significantly correlated with the presence of eggs in the study population. In conclusion, the development of feasible, long-term control policies and strategies for the elimination of C. sinensis in Korea is still required.
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http://dx.doi.org/10.3347/kjp.2020.58.6.647DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7806425PMC
December 2020

Surveillance on the Vivax Malaria in Endemic Areas in the Republic of Korea Based on Molecular and Serological Analyses.

Korean J Parasitol 2020 Dec 29;58(6):609-617. Epub 2020 Dec 29.

Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon 24341, Korea.

Plasmodium vivax reemerged in 1993. It has been sustained for more than 25 years and become one of the important indigenous parasitic diseases in northern and western parts of the Republic of Korea near the demilitarized zone. In particular, relapse is a significant concern for the control of malaria, as short- and long-term incubation periods vary among those infected in Korea. In this study, the prevalence of asymptomatic carriers was examined among residents of high endemic areas of vivax malaria during nonseasonal transmission of mosquitoes. Blood samples from 3 endemic regions in northwestern Korea were evaluated by microscopic examination, rapid diagnostic testing, and nested PCR to identify asymptomatic patients carrying malaria parasites in the community. However, no positive malaria case among residents of endemic areas was detected. Additionally, serological analysis was carried out to measure antibodies against 3 antigenic recombinant proteins of P. vivax, merozoite surface protein 1-19, circumsporozoite surface protein-VK210, and liver-stage antigen (PvLSA-N), by the protein array method. Interestingly, seropositivity of sera between previous exposure and samples without exposure to malaria was significantly higher using the PvLSA-N antigen than the other antigens, suggesting that PvLSA-N can be used as a serological marker to analyze the degree of exposure for malaria transmission in endemic areas. This indicates a very low asymptomatic carrier prevalence during the nonmalaria season in the endemic areas of Korea.
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http://dx.doi.org/10.3347/kjp.2020.58.6.609DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7806437PMC
December 2020

Outbreak of Cyclosporiasis in Korean Travelers Returning from Nepal.

Korean J Parasitol 2020 Oct 22;58(5):589-592. Epub 2020 Oct 22.

Division of Vectors & Parasitic Diseases, Korea Disease Control and Prevention Agency, Cheongju 28159, Korea.

Cyclospora cayetanensis is an apicomplexan protozoan and is one of the most common pathogens causing chronic diarrhea worldwide. Eight stool samples with diarrheal symptom out of 18 Korean residents who traveled to Nepal were obtained, and examined for 25 enteropathogens including 16 bacterial species, 5 viral species, and 4 protozoans in stool samples as causative agents of water-borne and food-borne disease. Only C. cayetanensis was detected by nested PCR, and 3 PCR-positive samples were sequenced to confirm species identification. However, the oocysts of C. cayetanensis in fecal samples could not be detected by direct microscopy of the stained sample. As far as we know, this is the first report of a group infection with C. cayetanensis from a traveler visiting Nepal, and the second report of a traveler's diarrhea by C. cayetanensis imported in Korea.
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http://dx.doi.org/10.3347/kjp.2020.58.5.589DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7672228PMC
October 2020

Prevalence of Toxocariasis and Its Risk Factors in Patients with Eosinophilia in Korea.

Korean J Parasitol 2020 Aug 26;58(4):413-419. Epub 2020 Aug 26.

Department of Tropical Medicine and Parasitology and Institute of Endemic Diseases, Seoul National University College of Medicine, Seoul 03080, Korea.

Eosinophilia occurs commonly in many diseases including allergic diseases and helminthic infections. Toxocariasis has been suggested as one cause of eosinophilia. The present study was undertaken to examine the prevalence of toxocariasis in patients with eosinophilia and to identify the risk factors for toxocariasis. This prospective cohort study recruited a total of 81 patients with eosinophilia (34 males and 47 females) who visited the outpatient clinic at Seoul National University Hospital from January 2017 to February 2018 and agreed to participate in this study. The prevalence of toxocariasis was examined by T. canis-specific ELISA, and the various risk factors for toxocariasis were evaluated by a questionnaire survey. Among 81 patients with eosinophilia, 18 were positive for anti-T. canis antibodies (22.2%); 88.9% were male (16/18) and 11.1% were female (2/18). Multivariate statistical analysis revealed that males (OR 21.876, 95% CI: 1.667-287.144) with a history of consuming the raw meat or livers of animals (OR 5.899, 95% CI: 1.004-34.669) and a heavy alcohol-drinking habit (OR 8.767, 95% CI: 1.018-75.497) were at higher risk of toxocariasis in patients with eosinophilia. Toxocariasis should be considered a potential cause of eosinophilia when the patient has a history of eating the raw meat or livers of animals in Korea. A single course of albendazole is recommended to reduce the migration of Toxocara larvae in serologically positive cases with eosinophilia.
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http://dx.doi.org/10.3347/kjp.2020.58.4.413DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7462808PMC
August 2020

Modelling infection in human cerebral organoids.

Emerg Microbes Infect 2020 Dec;9(1):1943-1954

Division of Intractable Diseases, Center for Biomedical Sciences, Korea National Institute of Health, Korea Centers for Disease Control and Prevention, Cheongju, Republic of Korea.

Pluripotent stem cell-derived cerebral organoids have the potential to recapitulate the pathophysiology of human brain tissue, constituting a valuable resource for modelling brain disorders, including infectious diseases. , an intracellular protozoan parasite, infects most warm-blooded animals, including humans, causing toxoplasmosis. In immunodeficient patients and pregnant women, infection often results in severe central nervous system disease and fetal miscarriage. However, understanding the molecular pathophysiology of the disease has been challenging due to limited model systems. Here, we developed a new model system of infection using human brain organoids. We observed that tachyzoites can infect human cerebral organoids and are transformed to bradyzoites and replicate in parasitophorous vacuoles to form cysts, indicating that the asexual life cycle is efficiently simulated in the brain organoids. Transcriptomic analysis of -infected organoids revealed the activation of the type I interferon immune response against infection. In addition, in brain organoids, exhibited a changed transcriptome related to protozoan invasion and replication. This study shows cerebral organoids as physiologically relevant model systems useful for advancing the understanding of infections and host interactions.
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http://dx.doi.org/10.1080/22221751.2020.1812435DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7534270PMC
December 2020

Increasing Malaria Parasite Clearance Time after Chloroquine Therapy, South Korea, 2000-2016.

Emerg Infect Dis 2020 08;26(8):1852-1855

We reviewed the clinical efficacy of chloroquine for Plasmodium vivax malaria, the changing trend of parasite clearance time, and fever clearance time during 2000-2016 in South Korea. Median parasite clearance time and fever clearance time increased significantly over the study period. Chloroquine was mostly underdosed when used to treat P. vivax malaria.
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http://dx.doi.org/10.3201/eid2608.190687DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7392446PMC
August 2020

Diagnosis and Molecular Analysis on Imported Plasmodium ovale curtisi and P. ovale wallikeri Malaria Cases from West and South Africa during 2013-2016.

Korean J Parasitol 2020 Feb 29;58(1):61-65. Epub 2020 Feb 29.

Division of Vectors and Parasitic Diseases, Center for Laboratory Control of Infectious Disease, Korea Centers for Disease Control and Prevention, Chungbuk 28159, Korea.

Majority of the imported malaria cases in Korea is attributed to Plasmodium falciparum and P. vivax infections, whereas P. malariae and P. ovale infections are very rare. Falciparum and ovale malaria are mostly imported from Africa, while most of the vivax malaria cases are imported from Southeast Asia. Here, we report 6 Korean imported ovale malaria cases (4 males and 2 females) who had visited in Africa during 2013-2016. These subjects were diagnosed with P. ovale based on microscopic findings, Plasmodium species-specific nested-PCR, and phylogenetic clade using 18S rRNA gene sequences. We identified 2 P. ovale subtypes, 1 P. ovale curtisi (classic type) and 5 P. ovale wallikeri (variant type). All patients were treated with chloroquine and primaquine, and no relapse or recrudescence was reported for 1 year after treatment. With increase of travelers to the countries where existing Plasmodium species, the risk of Plasmodium infection is also increasing. Molecular monitoring for imported malaria parasites should be rigorously and continuously performed to enable diagnosis and certification of Plasmodium spp.
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http://dx.doi.org/10.3347/kjp.2020.58.1.61DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7066446PMC
February 2020

Molecular detection of free-living amoebae from Namhangang (southern Han River) in Korea.

Sci Rep 2020 01 15;10(1):335. Epub 2020 Jan 15.

Department of Microbiology, Ajou University School of Medicine, Suwon, 16499, Republic of Korea.

The free-living amoebae Naegleria spp. and Acanthamoeba spp. exist in the natural environment and are sometimes causal agents of lethal primary amoebic meningoencephalitis (PAM), amoebic keratitis (AK) and granulomatous amebic encephalitis (GAE) in humans, respectively. To ascertain the existence of free-living amoebae in Korea, water samples were collected from the Korean hydrosphere, Namhangang (southern Han River), an active location for water skiing and recreation. Samples underwent two-step filtration and were cultured on non-nutrient agar medium with inactivated E. coli. The remaining samples were subjected to PCR for primarily the 18S small ribosomal RNA gene and gene sequencing. Similarities in 18S rDNA sequences, in comparison with various reference amoebae in GenBank, showed 86~99% homology with N. gruberi, N. philippinensis, N. clarki, A. polyphaga, A. castellannii, and Hartmannella (Vermamoeba) vermiformis. Therefore, this study will be useful for seasonal detection of free-living amoebae from various Korean hydrospheres in future studies.
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http://dx.doi.org/10.1038/s41598-019-57347-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6962209PMC
January 2020

Infection Status with Digenetic Trematode Metacercariae in Fishes from Coastal Lakes in Gangwon-do, Republic of Korea.

Korean J Parasitol 2019 Dec 31;57(6):681-690. Epub 2019 Dec 31.

Infection Disease Intelligence Division, Gangwon Institute of Health and Environment, Chuncheon 24203, Korea.

The infection status of digenetic trematode metacercariae (DTM) was investigated in fishes from coastal lakes in Gangwon-do, the Republic of Korea (Korea). All fishes collected in 5 lakes were examined with the artificial digestion method. More than 10 species, i.e., Metagonimus spp., Pygidiopsis summa, Centrocestus armatus, Metorchis orientalis, M. taiwanensis, Clinostomum complanatum, Echinostoma spp., Stictodora spp., Diplostomum sp. and Diplostomid No. 1. by Morita (1960), of DTM were detected in fishes from 5 coastal lakes in Gangwon-do. Metagonimus spp. metacercariae were found in 52 (41.3%) out of 126 sea rundace, Tribolodon hakonensis, from 5 lakes, and their density was 14.6 per fish infected. P. summa metacercariae were detected in 48 (84.2%) out of 57 mullets from 5 lakes, and their density was 316 per fish infected. C. armatus metacercariae were detected in 7 (14.6%) T. hakonensis and 3 (15.0%) Tridentiger brevispinis from Hyang-ho, and 5 (19.2%) Acanthogobius flavimanus from Gyeongpo-ho. Stictodora spp. metacercariae were found in 4 fish species, i.e., Tridentiger obscurus, Tridentiger trigonocephalus, Chelon haematocheilus, and Acanthogobius lactipes, from Gyeongpo-ho. Total 15 C. complanatum metacercariae were detected in 2 (9.1%) crucian carp, Carassius auratus, from Songji-ho. M. taiwanensis metacercariae were found in T. hakonensis from Hyang-ho and Gyeongpo-ho and in Pseudorasbora parva from Gyeongpo-ho. Total 11 M. orientalis metacercariae were detected in 3 (6.3%) T. hakonensis from Hyang-ho. From the above results, it was confirmed that various species of DTM are infected in fishes from coastal lakes in Gangwon-do, Korea.
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http://dx.doi.org/10.3347/kjp.2019.57.6.681DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6960247PMC
December 2019

Annual Fluctuation in Chigger Mite Populations and Infections in Scrub Typhus Endemic Regions of South Korea.

Osong Public Health Res Perspect 2019 Dec;10(6):351-358

Division of Vectors and Parasitic Diseases, Korea Centers for Disease Control and Prevention, Cheongju, Korea.

Objectives: Chigger mites are vectors for scrub typhus. This study evaluated the annual fluctuations in chigger mite populations and infections in South Korea.

Methods: During 2006 and 2007, chigger mites were collected monthly from wild rodents in 4 scrub typhus endemic regions of South Korea. The chigger mites were classified based on morphological characteristics, and analyzed using nested PCR for the detection of .

Results: During the surveillance period, the overall trapping rate for wild rodents was 10.8%. In total, 17,457 chigger mites (representing 5 genera and 15 species) were collected, and the average chigger index (representing the number of chigger mites per rodent), was 31.7. The monthly chigger index was consistently high (> 30) in Spring (March to April) and Autumn (October to November). The mite species included (43.5%), (18.9%), (18.1%), (10.6%), and (3.6%). and populations, were relatively higher in Autumn. Monthly infection rates in wild rodents (average: 4.8%) and chigger mites (average: 0.7%) peaked in Spring and Autumn.

Conclusion: The findings demonstrated a bimodal pattern of the incidence of infections. Higher infection rates were observed in both wild rodents and chigger mites, in Spring and Autumn. However, this did not reflect the unimodal incidence of scrub typhus in Autumn. Further studies are needed to identify factors, such as human behavior and harvesting in Autumn that may explain this discordance.
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http://dx.doi.org/10.24171/j.phrp.2019.10.6.05DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6927423PMC
December 2019

Molecular Prevalence and Genotypes of Cryptosporidium parvum and Giardia duodenalis in Patients with Acute Diarrhea in Korea, 2013-2016.

Korean J Parasitol 2019 Oct 31;57(5):531-536. Epub 2019 Oct 31.

Division of Vectors and Parasitic Diseases, Centers for Disease Control and Prevention, Osong 28159, Korea.

Cryptosporidium parvum and Giardia duodenalis are the main diarrhea-causing parasitic pathogens; however, their prevalence in Korea is unknown. Here, we conducted a survey to determine the prevalence and genotype distribution of these 2 pathogens causing acute diarrhea in 8,571 patients hospitalized in 17 Regional Institute of Health Environment sites in Korea, during 2013-2016. C. parvum and G. duodenalis were detected and genotyped by nested PCR, and the isolate were molecularly characterized by sequencing the glycoprotein 60 (Gp60) and β-giardin genes, respectively. The overall prevalence of C. parvum and G. duodenalis was 0.37% (n=32) and 0.55% (n=47), respectively, and both pathogens were more prevalent in children under 9 years old. Molecular epidemiological analysis showed that the C. parvum isolates belonged to the IIa family and were subtyped as IIaA13G2R1, IIaA14G2R1, IIaA15G2R1, and IIaA18G3R1. Analysis of the β-giardin gene fragment from G. duodenalis showed that all positive strains belong to assemblage A. This is the first report on the molecular epidemiology and subtyping of C. parvum and G. duodenalis in such a large number of diarrheal patients in Korea. These results highlight the need for continuous monitoring of these zoonotic pathogens and provide a basis for implementing control and prevention strategies. Further, the results might be useful for epidemiological investigation of the source of outbreak.
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http://dx.doi.org/10.3347/kjp.2019.57.5.531DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6851252PMC
October 2019

Infection Status with Clinostomum complanatum Metacercariae in Fish from Water Systems of Nakdong-gang (River) in Korea.

Korean J Parasitol 2019 Aug 31;57(4):389-397. Epub 2019 Aug 31.

Division of Vectors and Parasitic Diseases, Centers for Disease Control and Prevention, Osong 28159, Korea.

The infection status of Clinostomum complanatum metacercariae (CcMc) was broadly surveyed in fishes from water systems of Nakdong-gang (River) in the Republic of Korea (Korea) for 5 years. All 4,468 fishes collected were individually examined by the artificial digestion methods. No CcMc were detected in fishes from Naeseongcheon in Yecheon-gun, Gigyecheon in Gyeongju-si, Gyeongsangbuk-do, and Hamancheon in Haman-gun, Gyeongsangnam-do. In fishes from Wicheon in Gunwi-gun, Gyeongsangbuk-do, CcMc were detected in 180 (15.4%) out of 1,168 fishes and their intensity was 5.8 per fish infected. The prevalences with CcMc in positive fish species from 3 other surveyed areas, i.e., Banbyeoncheon in Yeongyang-gun, Nakdong-gang in Sangju-si and Hoecheon in Goryeong-gun, in Gyeongsangbuk-do were 19.3%, 33.3%, and 19.0% and their intensities were 1.5, 17.6, and 2.6 per fish infected respectively. In fishes from Yangcheon in Sancheong-gun, Gyeongsangnam-do, CcMc were detected in 811 (45.6%) out of 1,779 fishes examined and their intensity was 9.8 per fish infected. The prevalence was most high in Squalidus spp. (97.7%) and followed by acheilognathinid fish (66.8%), Pungtungia herzi (52.0%), rasborinid fish (39.6%) and Hemibarbus spp. (25.9%) from Yangcheon. The intensity was also most high in Squalidus spp. (27.0). The endemicity with CcMc was very low in fishes from water systems of Nakdong-gang in the east coast of Korea. Conclusively, it is confirmed that various fish species act as the second intermediate hosts of C. complanatum, and the endemicities of CcMc are more or less different by the fish species and group from Yangcheon, in Sancheong-gun, Gyeongsangnam-do, Korea.
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http://dx.doi.org/10.3347/kjp.2019.57.4.389DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6753292PMC
August 2019

Detection and characterization of an emerging type of sp. similar to for the first case of human babesiosis and ticks in Korea.

Emerg Microbes Infect 2019 ;8(1):869-878

a Division of Vectors and Parasitic Diseases , Korea Center for Disease Control and Prevention , Cheongju , Korea.

Babesiosis is a tick-transmitted intraerythrocytic zoonosis. In Korea, the first mortalities were reported in 2005 due to Babesia sp. detection in sheep; herein we report epidemiological and genetic characteristics of a second case of babesiosis. Microscopic analysis of patient blood revealed polymorphic merozoites. To detect Babesia spp., PCR was performed using Babesia specific primers for β-tubulin, 18S rDNA, COB, and COX3 gene fragments. 18S rDNA analysis for Babesia sp., showed 98% homology with ovine Babesia sp. and with Babesia infections in Korea in 2005. Moreover, phylogenetic analysis of 18S rDNA, COB, and COX3 revealed close associations with . For identifying the infectious agent, (296) and (301) were collected around the previous residence of the babesiosis patient. Babesia genes were identified in three : one sample was identified as and two samples were 98% homologous to . Our study is the first direct confirmation of the infectious agent for human babesiosis. This case most likely resulted from tick bites from ticks near the patient house of the babesiosis patient. has been implicated as a vector of and other Babesia sp. infections.
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http://dx.doi.org/10.1080/22221751.2019.1622997DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6566668PMC
September 2019

Infection Status with Clonorchis sinensis Metacercariae in Fish from Yangcheon (Stream) in Sancheong-gun, Gyeongsangnam-do, Korea.

Korean J Parasitol 2019 Apr 30;57(2):145-152. Epub 2019 Apr 30.

Division of Vectors and Parasitic Diseases, Centers for Disease Control and Prevention, Osong 28159, Korea.

The infection status with Clonorchis sinensis metacercariae (CsMc) was examined in freshwater fishes from Yangcheon (a branch of Gyeongho-gang), which is located in Sancheong-gun, Gyeongsangnam-do, the Republic of Korea. Total 2,201 fishes in 26 species were examined by the artificial digestion method through 7 years. CsMc were detected in 1,171 (53.2%) fishes in 21 spp. (80.8%) and their density was 85 per fish infected. Total 532 (99.6%) out of 534 Pungtungia herzi (index fish) examined were infected with 147 CsMc per fish infected. Metacercarial densities in this fish were highest in 2015 (179 CsMc), followed by 2012 (168), 2013 (152), 2016 (145), 2014 (114), and 2017 (89) respectively. In the gobioninid fish group, i.e., P. herzi, Sarcocheilichthys spp., Squalidus spp., Pseudogobio esocinus, Hemibarbus longirostris, and Hemibarbus labeo, 841 (92.7%) fishes were infected with 117 CsMc per fish infected. Total 250 (54.7%) acheilognathinid fish (bitterlings), Acheilognathus spp. and Acanthorhodeus spp. were infected with 5.8 CsMc. In the rasborinid fish (chubs) group, i.e., Zacco platypus, Zacco temminckii, and Zacco koreanus, 77 (13.7%) out of 563 fish examined were infected with 2.4 CsMc in average. The susceptibility indices of CsMc were 49.09 in the overall positive fish group, 104.15 in the gobioninid group, 3.17 in the acheilognathinid group and 0.35 in the rasborinid fish group respectively. Only 1 CsMc was detected in 3 fish species, Coreoperca herzi, Channa argus, and Lepomis macrochirus, respectively. Conclusively, it was confirmed that CsMc are moderately prevalent in fishes from Yangcheon in Sancheon-gun, Gyeongsangnam-do, Korea.
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http://dx.doi.org/10.3347/kjp.2019.57.2.145DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6526209PMC
April 2019

Metagonimus miyatai ameliorates dextran sodium sulfate-induced colitis in mice.

Parasitol Int 2020 Feb 8;74:101924. Epub 2019 May 8.

Division of Vectors and Parasitic Diseases, Centers for Disease Control and Prevention, Republic of Korea. Electronic address:

Inflammatory bowel disease (IBD) is an inflammatory disease caused by the activity of effector immune cells, such as the overproduction of inflammatory cytokines. Helminth immunomodulation in the host has been shown to have therapeutic implications in IBD. In the present study, we investigated whether Metagonimus miyatai infection could ameliorate inflammatory diseases. Mice were infected with M. miyatai, and colitis was then induced through oral administration of dextran sulfate sodium (DSS). Weight loss, stool consistency, gross bleeding, colon length, and tissue inflammation were assessed by macroscopic and microscopic examinations. In addition, regulatory cytokine expression was observed in colon tissue by reverse transcription polymerase chain reaction. The results showed that M. miyatai infection decreased the clinical severity of DSS-induced colitis, including weight loss, bloody diarrhea, shortening of the colon, and colon tissue damage in mice (p < .05). The expression levels of tumor necrosis factor-α, interleukin-1b, and cyclooxygenase-2 in mice infected with helminth were lower than those in DSS-treated mice without helminthic infection (p < .05). The results of the research showed that pre-infection with M. miyatai ameliorated DSS-induced colitis in mice and may be a novel therapeutic strategy for the treatment of immunological diseases.
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http://dx.doi.org/10.1016/j.parint.2019.05.002DOI Listing
February 2020

Severe vivax malaria in the Republic of Korea during the period 2000 to 2016.

Travel Med Infect Dis 2019 Jul - Aug;30:108-113. Epub 2019 May 1.

Department of Internal Medicine, Yonsei University College of Medicine, Yonsei-ro 50-1, Seodaemun-gu, Seoul, Republic of Korea. Electronic address:

Background: There has been a marked increase in the reporting of confirmed vivax malaria cases in certain geographical areas. This study investigated cases of severe vivax malaria in the Republic of Korea.

Methods: We retrospectively reviewed the medical records of adult patients diagnosed with vivax malaria in the Republic of Korea during the period 2000 to 2016. Diagnosis was made using the World Health Organization criteria, with the exception of parasite density.

Results: Among 1366 malaria cases, 255 (18.7%) were classified as severe vivax malaria, and 46 (3.4%) required intensive care. None of patients died of malaria. Patients with severe vivax malaria were older and had more comorbidity. The enrollment periods were classified into three groups, 2000 to 2005 (506 cases), 2006 to 2010 (696 cases), and 2011 to 2016 (304 cases). Malaria cases decreased from 2011 to 2016, but severe malaria cases increased significantly over time (14.3%, 20.1%, and 22.8%, p = 0.003). Common severe manifestations were shock (45.6%) and jaundice (43.1%).

Conclusions: Cases of severe malaria increased, and shock and jaundice were the predominant findings of severe vivax malaria in the Republic of Korea.
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http://dx.doi.org/10.1016/j.tmaid.2019.04.013DOI Listing
October 2019

Infection Status of Isthmiophora hortensis Metacercariae in Dark Sleepers, Odontobutis Species, from Some Water Systems of the Republic of Korea.

Korean J Parasitol 2018 Dec 31;56(6):633-637. Epub 2018 Dec 31.

Division of Vectors and Parasitic Diseases, Centers for Disease Control and Prevention, Osong 28159, Korea.

Present study was performed to survey on infection status of Isthmiophora hortensis (formerly Echinostoma hortense) metacercariae (IhMc) in dark sleepers, Odontobutis spp., from some water systems of the Republic of Korea. A total of 237 Odontobutis spp. was collected in the water systems of 5 rivers, i.e., Mangyeong-gang (gang means river), Geum-gang, Tamjin-gang, Seomjin-gang, and Nakdong-gang. They were all examined with artificial digestion method for 5 years (2013-2017). A total of 137 (57.8%) Odontobutis spp. were infected with 14.8 IhMc in average. The prevalence was the highest in Nakdong-gang areas (62.9%) and followed by in Mangyeong-gang (57.1%), Geum-gang (56.3%), Tamjin-gang (54.8%), and Seomjin-gang (53.9%) areas. Metacercarial densities were 28.1 (Geum-gang), 13.9 (Mangyeong-gang), 13.3 (Nakdong-gang), 13.1 (Tamjin-gang), and 2.3 (Seomjin-gang) per infected fish. Especially, in case of Yugucheon (cheon means stream), a branch of Geum-gang, IhMc were detected in all fish (100%) examined and their density was about 48 per fish. By the present study, it was confirmed that the infection status of IhMc is more or less different by the surveyed areas and the dark sleepers, Odontobutis spp., are suitable fish hosts of I. hortensis.
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http://dx.doi.org/10.3347/kjp.2018.56.6.633DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6327203PMC
December 2018

Development of Molecular Diagnosis Using Multiplex Real-Time PCR and T4 Phage Internal Control to Simultaneously Detect Cryptosporidium parvum, Giardia lamblia, and Cyclospora cayetanensis from Human Stool Samples.

Korean J Parasitol 2018 Oct 31;56(5):419-427. Epub 2018 Oct 31.

Department of Parasitology and Tropical Medicine, Seoul National University College of Medicine, and Institute of Endemic Diseases, Seoul National University Medical Research Center, Seoul 03080, Korea.

This study aimed to develop a new multiplex real-time PCR detection method for 3 species of waterborne protozoan parasites (Cryptosporidium parvum, Giardia lamblia, and Cyclospora cayetanensis) identified as major causes of traveler's diarrhea. Three target genes were specifically and simultaneously detected by the TaqMan probe method for multiple parasitic infection cases, including Cryptosporidium oocyst wall protein for C. parvum, glutamate dehydrogenase for G. lamblia, and internal transcribed spacer 1 for C. cayetanensis. Gene product 21 for bacteriophage T4 was used as an internal control DNA target for monitoring human stool DNA amplification. TaqMan probes were prepared using 4 fluorescent dyes, FAMTM, HEXTM, Cy5TM, and CAL Fluor Red® 610 on C. parvum, G. lamblia, C. cayetanensis, and bacteriophage T4, respectively. We developed a novel primer-probe set for each parasite, a primer-probe cocktail (a mixture of primers and probes for the parasites and the internal control) for multiplex real-time PCR analysis, and a protocol for this detection method. Multiplex real-time PCR with the primer-probe cocktail successfully and specifically detected the target genes of C. parvum, G. lamblia, and C. cayetanensis in the mixed spiked human stool sample. The limit of detection for our assay was 2×10 copies for C. parvum and for C. cayetanensis, while it was 2×103 copies for G. lamblia. We propose that the multiplex real-time PCR detection method developed here is a useful method for simultaneously diagnosing the most common causative protozoa in traveler's diarrhea.
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http://dx.doi.org/10.3347/kjp.2018.56.5.419DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6243187PMC
October 2018

Prevention and Control Strategies for Parasitic Infections in the Korea Centers for Disease Control and Prevention.

Korean J Parasitol 2018 Oct 31;56(5):401-408. Epub 2018 Oct 31.

Department of Parasitology and Tropical Medicine, Inha University School of Medicine, Incheon 22212, Korea.

Korea is successfully controlled intestinal parasitic infections owing to economic development and high health consciousness. The Division of Vectors and Parasitic Diseases (formerly the Division of Malaria and Parasitology) is in the Center for Laboratory Control of Infectious Diseases of the Korea Centers for Disease Control and Prevention. It has been the governmental agency responsible for controlling and leading scientific research on parasitic diseases. The Division of Vectors and Parasitic Diseases has conducted and funded basic research and disseminated the research results to various medical fields, ultimately promoting public health in Korea. Among the noteworthy achievements of this division are the national surveillance of healthcare-associated parasitic infections, prevention and control for parasitic infections, and the elimination of lymphatic filariasis from Korea. On a broader scale, the division's research programs and academic supports were influential in preventing and treating infectious parasitic diseases through public policies and laws. In this review, we summarize the past and present role of the Division of Vectors and Parasitic Diseases in preventing and treating infectious parasitic diseases in Korea.
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http://dx.doi.org/10.3347/kjp.2018.56.5.401DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6243194PMC
October 2018

A 21.6 kDa tegumental protein of Clonorchis sinensis induces a Th1/Th2 mixed immune response in mice.

Immun Inflamm Dis 2018 12 9;6(4):435-447. Epub 2018 Oct 9.

Division of Vectors and Parasitic Diseases, Center for Laboratory Control of Infectious Diseases, Korea Centers for Disease Control & Prevention, Osong, 28159, Republic of Korea.

Introduction: Clonorchis sinensis is a major parasite affecting the Korea population. Despite the high infection rate and pathogenicity, very few studies have been conducted to investigate the immune responses against the proteins of C. sinensis.

Methods: In this study, in vitro immune response induced by a recombinant 21.6 kDa tegumental protein derived from C. sinensis (rCsTegu21.6) was confirmed in murine dendritic cells and T cells. For the in vivo analysis, each mouse was immunized three times. Total serum IgG and T cell cytokine production were determined by ELISA, while T cell proliferation was detected by a WST (Water-Soluble Tetrazolium salt)-1 assay.

Results: In vitro tests indicated that rCsTegu21.6 treatment increased the expression of surface molecules, such as CD40 (77%), CD80 (52%) and CD86 (46%), on murine dendritic cells and the secretion of cytokines (TNF-α, IL-6, IL-1β, IL-10, and IL-12p70). Moreover, co-culturing dendritic cells activated by rCsTegu21.6 with allogenic T cells induced T cell proliferation over time. rCsTegu21.6 also stimulated specific antibody production and cytokine secretion [IL-2, IL-4, and interferon (IFN)-γ)] from T cells following immunization in vivo. Notably, rCsTegu21.6 predominantly induced IgG1 production and secretion of the Th2 cytokine IL-4, regardless of the type of adjuvant used.

Conclusion: These results serve as a foundation for the development of tegumental protein-based vaccines against C. sinensis.
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http://dx.doi.org/10.1002/iid3.235DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6247233PMC
December 2018

Infection Status with Metagonimus spp. Metacercariae in Fishes from Seomjin-gang and Tamjin-gang in Republic of Korea.

Korean J Parasitol 2018 Aug 31;56(4):351-358. Epub 2018 Aug 31.

Division of Microbiology, Jeollanam-do Institute of Health and Environment, Muan 58568, Korea.

To grasp the infection status of Metagonimus spp. metacercariae (MsMc), the freshwater fishes were surveyed from Seomjin-gang (river) and Tamjin-gang in the Republic of Korea. Total 1,604 fishes from 7 local sites of Seomjin-gang and 1,649 fishes from 2 sites of Tamjin-gang were examined for 6 years (2012-2017) by the artificial digestion method. MsMc were detected in fishes from 7 sites, i.e., Osucheon in Imsil-gun (36.3% fish in 6 spp.), Seomjin-gang in Sunchanggun (49.8% in 18 spp.), Songdaecheon in Namwon-si (64.5% in 8 spp.), Seomjin-gang in Gokseong-gun (72.4% in 14 spp.) and in Gurye-gun (78.8% in 17 spp.), Hoengcheon (75.9% in 11 spp.) and Namsancheon (58.9% in 7 spp.) in Hadong-gun. Their average densities were 4.2, 86.8, 39.9, 43.1, 246.5, 173.6 and 67.5 per fish infected respectively. Prevalence with MsMc in rasborinid fish from Seomjin-gang was 89.2% and their intensity was 73.6 per fish infected. Endemicities of MsMc in rasborinid fish from Seomjin-gang were significantly higher in fishes from the lower reaches (prevalence: 98.7%; density: 137) rather than in fishes from the middle (93.5%; 38) and upper (72.4%; 13) reaches. MsMc were also detected in 56.1% and 66.4% fishes from 2 surveyed areas, i.e., the middle reaches in Jangheung-gun and the lower reaches in Gangjin-gun, of Tamjin-gang, and their densities were 147 and 121 per fish infected. In susceptible fishes from Tamjin-gang, the prevalence was 84.1% and density was 227 per fish infected. By the present study, it was confirmed that MsMc is highly prevalent in the fishes from Seomjin-gang and Tamjin-gang in Korea.
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http://dx.doi.org/10.3347/kjp.2018.56.4.351DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6137295PMC
August 2018

Infections with Centrocestus armatus Metacercariae in Fishes from Water Systems of Major Rivers in Republic of Korea.

Korean J Parasitol 2018 Aug 31;56(4):341-349. Epub 2018 Aug 31.

Infection Disease Intelligence Division, Gangwon Institute of Health and Environment, Chuncheon 24203, Korea.

The infection status of Centrocestus armatus metacercariae (CaMc) was broadly surveyed in freshwater fishes from major river systems in the Republic of Korea (Korea) during 2008-2017. A total of 14,977 fishes was caught and examined by the artificial digestion method. CaMc were detected in 3,818 (97.1%) (2,114 Z. platypus: 96.1% and 1,704 Z. temminckii: 98.4%) out of 3,932 Zacco spp. examined and their density was 1,867 (2,109 in Z. platypus and 1,567 in Z. temminckii) per fish infected. The prevalences with CaMc were high, 93.7-100%, in Zacco spp. from all surveyed areas. However, their densities were more or less different by the surveyed areas and fish species. They were most high in Nakdong-gang in Gyeongsangnam-do (4,201 in average), and followed by Geum-gang (2,343), Nakdong-gang in Gyeongsangbuk-do (1,623), Han-gang (1,564), Tamjin-gang and Yeongsan-gang (1,540), streams in the east coast (1,028), Seomjin-gang (488) and Mangyeong-gang (170). In another species of rasborinid fish, Opsariichthys uncirostris amurensis, CaMc were detected in 222 (74.8%) out of 297 ones examined and their density was 278 (1-4,480) per fish infected. CaMc were also detected in total 41 fish species except for the rasborinid fish, Z. platypus, Z. temminckii and O. uncirostris amurensis. Conclusively, it was confirmed that among the 3 species of rasborinid fish, Z. platypus and Z. temminckii are highly prevalent and O. uncirostris amurensis is moderately prevalent with CaMc. Additionally, we could know that variety of fish species act as the second intermediate hosts of C. armatus in Korea.
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http://dx.doi.org/10.3347/kjp.2018.56.4.341DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6137297PMC
August 2018

Infections with Zoonotic Trematode Metacercariae in Yellowfin Goby, Acanthogobius flavimanus, from Coastal Areas of Republic of Korea.

Korean J Parasitol 2018 Jun 30;56(3):259-265. Epub 2018 Jun 30.

Infection Disease Intelligence Division, Gangwon Institute of Health and Environment, Chuncheon 24203, Korea.

To investigate the infection status of zoonotic trematode metacercariae in yellowfin goby, Acanthogobius flavimanus, from coastal areas of the Republic of Korea (Korea), we examined total 344 gobies from 21 localities with an artificial digestion method from 2013 to 2017. The metacercariae of Stictodora lari were most frequently detected in 45.3% goby from 7 localities, i.e., Taean-gun (Chungcheongnam-do), Gochang-gun (Jeollabuk-do), Muan-gun, Shinan-gun, Haenam-gun (Jeollanam-do), Hadong-gun and Goseong-gun (Gyeongsangnam-do). Their infection rates were 90.0%, 66.7%, 46.7%, 8.0%, 3.3%, 26.7%, and 86.7% and intensities were 1,090, 6.2, 1.6 1.0, 2.0, 2.0, and 7.2 metacercariae per fish infected respectively. Heterophyopsis continua metacercariae were found in 38.2% goby from 6 localities, i.e., Gochang-gun, Muan-gun, Shinan-gun, Gangjin-gun, Boseong-gun (Jeollanam-do) and Goseong-gun, and their intensities were relatively low, 1-21 metacercariae. Stictodora fuscata metacercariae were detected in 61.3% goby from 4 localities, i.e., Taean-gun, Gochang-gun, Hadong-gun and Goseong-gun. Their infection rates were 90.0%, 53.3%, 5.9%, and 73.3% and intensities were 1,081, 3.1, 3.0, and 10.2 metacercariae per fish infected respectively. Heterophyes nocens metacercariae were found in 55.0% goby from Muan-gun and Shinan-gun. Total 3 metacercariae of Isthmiophora hortensis were detected in 2 (8.0%) gobies from Shinan-gun. Total 15 metacercariae of Centrocestus armatus were detected in 5 gobies (33.3%) from Gyeongpo-ho (ho means lake) in Gangneung-si, Gangwon-do. The present study suggests that yellowfin goby, A. flavimanus, acts as the infection sources of zoonotic intestinal flukes in western and southern coastal areas than in eastern coastal areas of Korea.
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http://dx.doi.org/10.3347/kjp.2018.56.3.259DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6046562PMC
June 2018

Venom allergen-like protein 28 in Clonorchis sinensis: four epitopes on its surface and the potential role of Cys124 for its conformational stability.

Parasitol Res 2018 Aug 6;117(8):2521-2530. Epub 2018 Jun 6.

Division of Vectors and Parasitic Diseases, Center for Laboratory control of Infectious Diseases, Korea Centers for Disease Control and Prevention, Chungbuk, 28159, Republic of Korea.

Venom allergen-like (VAL) proteins are important to host-parasite interactions. We previously demonstrated that a Clonorchis sinensis VAL (CsVAL) protein-derived synthetic peptide suppresses allergic and inflammatory responses. However, little is known regarding the physicochemical and antigenic properties of CsVAL proteins. Here, we identified a novel 194 amino acid VAL protein, named C. sinensis VAL 28 (CsVAL28), and characterized its functional motifs and structural details as a new member of the CAP superfamily. Unlike members of the Schistosoma mansoni VAL (SmVAL) family, CsVAL28 has a single CAP1 motif and six highly conserved disulfide bond-forming cysteines. Tertiary models of wild-type CsVAL28 and mutants were built using SmVAL4 as template via homology modeling. Normal mode analysis predicted that disulfide bond breaking by mutation of cysteine 124 to serine would greatly affect protein mobility. Four major immunoreactive linear epitopes were identified in the surface-exposed region or its vicinity via epitope mapping, using sera from clonorchiasis patients and healthy controls. Our findings provide in-depth knowledge on the structure-function properties of VAL proteins and may help determine highly antigenic regions for developing new diagnostic approaches.
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http://dx.doi.org/10.1007/s00436-018-5941-4DOI Listing
August 2018

Infection Status with Metacercariae in Fish from Tamjin-gang (River) in Jeollanam-do, Republic of Korea.

Korean J Parasitol 2018 Apr 30;56(2):183-188. Epub 2018 Apr 30.

Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju 52727, Korea.

The present study was performed to investigate the infection status with metacercariae (CsMc) in fishes from 2 sites, the middle and lower reaches, of Tamjin-gang (River) in Jeollanam-do, the Republic of Korea. Total 1,132 fishes in 22 species were collected from the middle reaches in Jangheung-gun for 4 years (2014-2017) and 517 fishes in 17 species were also collected from the lower reaches in Gangjin-gun in 2014 and 2017. They were all individually examined with the artificial digestion method in our laboratory. CsMc were detected in 322 (28.5%) out of 1,132 fishes from Jangheung-gun, and in 161 (31.1%) out of 517 fishes from Gangjin-gun, and their densities were 51 and 57 per fish infected each. In the fish species with CsMc, positive rates were 61.5% in Jangheung-gun and 62.7% in Gangjin-gun. A total of 222 were examined and they were all infected with CsMc. The average intensity was 103 CsMc in the index fish, (95 in Jangheung-gun and 121 in Gangjin-gun). In bimonthly examined in 2017, the intensity was commonly most higher in March in 2 surveyed sites, however the significant seasonal endemicity was not showed. Conclusively, it was confirmed that CsMc is more or less prevalent in fishes from Tamjin-gang and their endemicity is higher in fish from the lower reaches in Gangjin-gun than the middle reaches in Jangheung-gun in Jeollanam-do, Korea.
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http://dx.doi.org/10.3347/kjp.2018.56.2.183DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5976021PMC
April 2018
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