Metacercarial density of Metagonimus yokogawai in Plecoglossus altivelis in Kyungpook province, Korea.

In order to determine the intensity of infection with the encysted larvae of Metagonimus yokogawai among Plecoglossus altivelis, sweetfish, caught at the rivers in Kyungpook Province, Korea were examined in the period from July to October, 1976. The data were compared with the results obtained from Tribolodon hakonensis, the sea-run dace, caught at the river Hyungsan in the Province. A total of 128 Plecoglossus altivelis were examined. All the fish were infected with the metacercaria of Metagonimus yokogawai. The metacercarial rate for the fluke in the flesh was higher than the rates in the fins and scales. The average number of larvae per sweetfish was 4,333, compared with the average of 1,541 from the sea-run dace. It was found that the highest number of encysted larvae was found in the flesh of sweetfish, whereas it was encountered on the scales of sea-run dace. In the distribution pattern of the cysts, there was no relationship between the size of fish and the intensity of infection.