Epidemiological studies of digenetic trematodes in Yongyang County, Kyungpook Province.

The present study was undertaken to determine the endemicity of trematode infections in Yongyang County, Kyungpook Province, Korea. One hundred and seventy-seven out of 955 residents examined were found to be infected with one or more kinds of helminths. The prevalence rate was 18.5%. Among them, 70 were found to be infected with Clonorchis sinensis, 74 with Metagonimus sp. and 24 with both flukes. The eggs of Fasciolidae were demonstrated from two specimens. The prevalence rate of clonorchiasis in males was 12.6%, while that in females was 3.6% (p less than 0.05). The prevalence of metagonimiasis in males was 12.0% and was also significantly higher than 6.1% in females (p less than 0.05). The intensity of both infections was significantly heavier in males than in females. The prevalence of both flukes was higher in residents of over 30 years of age than in those below that age. No correlation was found between the intensity and the age group. Among eight species of the fresh-water fish collected at the Panbyon River, Zacco temmincki was found to be the most frequently and heavily infested with metacercariae of Metagonimus sp., and Gnathopogon atromaculatus alone was found to be infested with metacercariae of Clonorchis sinensis. The present results suggest that Yongyang area still remains endemic with Clonorchis sinensis and Metagonimus sp. infection.