Endemic foci of Paragonimus westermani in Chilgok, Kyungpook Province, Korea.

By performing the county-wide surveys of Paragonimus westermani infection in several areas in the Chilgok county, Kyungpook Province, three endemic foci of Paragonimus westermani were found. The foci found in this survey were Haksan first dong, Haksan second dong, and Settom in Kumhwa village, all in Kasan myun, Chilgok county. In the three communities, the positive rates for the fluke among the residents by the intradermal test with Paragonimus antigen varied from 22.3 per cent to 25.0 per cent; school children from these areas showed infection rates above 50 per cent. The rate in males and females was 23.9 and 23.0 per cent, respectively. This difference was not significant. The presence and number of Semisulcospira snails and Astacus crayfish, the intermediate hosts of Paragonimus westermani in the stream communities and the high infection rates for the fluke in the residents were the supporting factors in determining the foci.