The infection status of freshwater fish with digenetic trematode metacercariae was examined in water systems of Hantangang and Imjingang (River), the Republic of Korea. A total of 877 (594 from Hantangang and 283 from Imjingang) fishes were examined by the artificial digestion methods. Clonorchis sinensis metacercariae were detected in 7 (1.2%) fishes (in 3 spp.) from Hantangang in Cheorwon-gun, Gangwon-do, and 40 (14.1%) fishes (in 7 spp.) from Munsancheon in Paju-si, Gyeonggi-do. The average densities were 1.9 and 35.6 per fish infected, respectively. Metagonimus spp. metacercariae were detected in 312 (52.5%) and 113 (39.9%) fishes from Hantangang and Imjingang, and their average densities were 47.5 and 9.6 per fish infected, respectively. Centrocestus armatus metacercariae were found in 161 (27.1%) and 70 (24.7%) fishes from Hantangang and Imjingang, and their average number per fish infected was 694 and 82, respectively. Echinostoma spp. metacercariae were detected in 50 (8.4%) and 94 (33.2%) fishes from Hantangang and Imjingang, and their average densities were 9.6 and 23.1 per fish infected, respectively. The infection status of fishes with metacercariae of Stephanoprora spp., Diplostomum spp., Clinostomum complanatum, Metorchis orientalis, and Metorchis taiwanensis were analyzed by surveyed regions. Conclusively, it was confirmed that C. sinensis metacercariae were quite commonly detected in fishes from Munsancheon but rarely from other localities, whereas the metacercariae of other digenetic trematodes were relatively prevalent in fishes from water systems of Hantangang and Imjingang in Korea.

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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., <i>Metagonimus</i> spp., <i>Pygidiopsis</i> <i>summa</i>, <i>Centrocestus</i> <i>armatus</i>, <i>Metorchis</i> <i>orientalis</i>, <i>M</i>. <i>taiwanensis</i>, <i>Clinostomum</i> <i>complanatum</i>, <i>Echinostoma</i> spp., <i>Stictodora</i> spp., <i>Diplostomum</i> sp. and Diplostomid No. 1. by Morita (1960), of DTM were detected in fishes from 5 coastal lakes in Gangwon-do. <i>Metagonimus</i> spp. metacercariae were found in 52 (41.3%) out of 126 sea rundace, <i>Tribolodon</i> <i>hakonensis</i>, from 5 lakes, and their density was 14.6 per fish infected. <i>P</i>. <i>summa</i> metacercariae were detected in 48 (84.2%) out of 57 mullets from 5 lakes, and their density was 316 per fish infected. <i>C</i>. <i>armatus</i> metacercariae were detected in 7 (14.6%) <i>T</i>. <i>hakonensis</i> and 3 (15.0%) <i>Tridentiger</i> <i>brevispinis</i> from Hyang-ho, and 5 (19.2%) <i>Acanthogobius</i> <i>flavimanus</i> from Gyeongpo-ho. <i>Stictodora</i> spp. metacercariae were found in 4 fish species, i.e., <i>Tridentiger</i> <i>obscurus</i>, <i>Tridentiger</i> <i>trigonocephalus</i>, <i>Chelon</i> <i>haematocheilus</i>, and <i>Acanthogobius</i> <i>lactipes</i>, from Gyeongpo-ho. Total 15 <i>C</i>. <i>complanatum</i> metacercariae were detected in 2 (9.1%) crucian carp, <i>Carassius</i> <i>auratus</i>, from Songji-ho. <i>M</i>. <i>taiwanensis</i> metacercariae were found in <i>T</i>. <i>hakonensis</i> from Hyang-ho and Gyeongpo-ho and in <i>Pseudorasbora</i> <i>parva</i> from Gyeongpo-ho. Total 11 <i>M</i>. <i>orientalis</i> metacercariae were detected in 3 (6.3%) <i>T</i>. <i>hakonensis</i> 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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A total of 673 ready-to-eat vegetable samples were collected in Korea from 2001 to 2002 and analyzed for the presence of Yersinia spp. We analyzed biotypes, serotypes, and susceptibility to 12 antibiotics and tested for virulence genes of pathogenic Yersinia enterocolitica isolates by PCR assay. Among the samples, 27 (4.0%) were found to be contaminated with Yersinia spp. Among the 27 strains of Yersinia spp. isolates, 18 strains (66.7%) of Y. enterocolitica, 5 strains (18.5%) of Y. frederiksenii, 3 strains (11.1%) of Y. intermedia, and 1 strain (3.7%) of Y. kristensenii were identified. According to the serotypes of Y. enterocolitica isolates, O:3 (11.1%) and O:5 (11.1%) were the most predominant, followed by O:8 (5.6%) and others (72.2%). For biotypes of Y. enterocolitica isolates, 1A (77.8%) was the most predominant, followed by 3B (11.1%), 3 (5.6%), and 5A (5.6%). Also, an antibiotic susceptibility test showed that Y. enterocolitica isolates were very susceptible to the antibiotics tested but highly resistant to ampicillin (94%), cephalothin (100%), and carbenicillin (83%). PCR assays with specific primers derived from yst and ail genes of Y. enterocolitica were applied to confirm the presence of pathogenic Y. enterocolitica. Among the 18 strains of Y. enterocolitica isolates, only 3 strains (O:3/1A, UT/3B, and UT/1A isolated from Chinese cabbage, onion, and spinach, respectively) were shown to have a virulence gene.