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

Abstract

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.

Endemicity of Zoonotic Trematode Metacercariae in Fish from Deokcheon-gang (River) in Sancheong-gun, Gyeongsangnam-do, Republic of Korea

“…Division of vectors and parasitic diseases of Korea DCPA (Korea Disease Control and Prevention Agency) has continuously investigated the endemicity of FZT infections in the riverside areas of southern regions of Korea [ 2 – 5 ]. The coworking group also surveyed the infection status of zoonotic trematode metacercariae (ZTM) in the infection sources of FZT, freshwater fish, to know the epidemiological situation in water systems of major rivers in Korea [ 6 – 18 ]. Cho et al [ 6 ] investigated the infection status of C. sinensis metacercariae (CsMc) in fishes from 3 wide regions by the latitudinal levels of Korean peninsula.…”

“…Sohn and Na [ 14 ] surveyed the infection status of DTM in freshwater fishes from 2 visiting sites of migratory birds, Junam-jeosuji (jeosuji means reservoir) and Woopo-neup (neup means swamp), in Gyeongsangnam-do, Korea. Recently, Sohn et al [ 17 , 18 ] reported the infection status of ZTM in freshwater fishes from Soyang-cheon (a branch stream of Mangyeong-gang in Wanju-gun, Jeollabuk-do) and the irrigation canal of Togyo-jeosuji (Reservoir in Cheorwon-gun, Gangwon-do), Korea.…”

“…In P. herzi from 2 rivers in southern region of Korea, Tamjin-gang and Seomjin-gang, SI was 103.2 and 34.8 [ 9 , 10 ]. Recently, Sohn et al [ 15 , 18 ] reported 48.2 and 90.8 (SI) in P. herzi from water systems of Geum-gang and Togyo-jeosuji in Cheorwon-gun, Gangwon-do. Accordingly, based on the SI of CsMc in the index fish, P. herzi , we can know that Wi-cheon and Yongjeon-cheon are highly endemic, Yang-cheon, Tamjin-gang and Togyo-jeosuji are moderately endemic, and Geum-gang, Seomjin-gang and Deokcheon-gang are more or less low endemic areas.…”

“…Sohn et al [ 25 ] also reported 55.4% and 57.7% prevalence, and 96 and 138 MsMc intensities in fishes from Seomjin-gang and Tamjin-gang respectively. Recently, prevalence of MsMc was 51.7%, 37.4%, and 74.1% and infection intensities were 30, 12 and 62 PFI respectively in fishes from the water systems of Geum-gang, Soyang-cheon and Togyo-jeosuji [ 15 , 17 , 18 ]. The prevalence of MsMc in this study is relatively higher than those of previous studies.…”

“…Prevalence of MsMc in chubs from water systems of Seomjin-gang and Tamjin-gang was 89.2% and 89.0%, and their infection intensities were 74 and 42 PFI [ 25 ]. Recently, MsMc were detected in 69.7%, 74.6%, and 98.1% chubs from the water systems of Geum-gang, Soyang-cheon and Togyo-jeosuji and their infection intensities were 20, 22, and 134 PFI respectively [ 15 , 17 , 18 ]. From the findings of previous studies, we can suppose that the endemicity with MsMc in this study is much higher than those in previous studies performed in Hantan-gang, Imjin-gang, Seomjin-gang, Tamjin-gang, Geum-gang and Soyang-cheon.…”