Intestinal trematodes infecting humans in Korea.

Sixteen species of intestinal trematodes have been recovered from humans in Korea. They include 10 species of the family Heterophyidae (Metagonimus yokogawai, M. takahashii, Heterophyes nocens, H. heterophyes, H. dispar, Heterophyopsis continua, Pygidiopsis summa, Stellantchasmus falcatus, Centrocestus armatus, and Stictodora fuscatum); one species of Diplostomidae (Fibricola seoulensis); three species of Echinostomatidae (Echinostoma hortense, E. cinetorchis, and Echinochasmus japonicus); one species of Plagiorchiidae (Plagiorchis sp.), and one species of Gymnophallidae (Gymnophalloides sp.). Biological and epidemiological studies have shown that all of these species are endemic to Korea except H. heterophyes and H. dispar, which were imported from the Middle East, and Plagiorchis sp., which has not been found in Korea. Several fresh water fish were found carrying metacercarial stages of M. yokogawai, M. takahashii, C. armatus, E. hortense, E. cinetorchis and E. japonicus. Brackish water fish were found to be the second intermediate host of H. nocens, H. continua, P. summa, S. falcatus, and/or S. fuscatum. Terrestrial snakes were the second intermediate (or paratenic) host of F. seoulensis. Among these intestinal flukes, M. yokogawai is the most common one in Korea.