Stools of the residents in a village in Saengbiryang-myon, Sanchong-gun, Kyongsangnam-do were examined for the eggs of intestinal helminths. In 1987, infection rate of 76 residents by Clonorchis sinensis was 80.3% with mean eggs per gram of feces (EPG) 27,781. C. sinensis-infected persons were treated once with praziquantel 60 mg/kg, q.i.d. Seventeen persons (22.4%) infected by Metagonimus yokogawai was coinfected with C. sinensis. In 1993, C. sinensis egg positive rate was 48.4% with mean EPG 5,929. Reinfection rate of follow-up cases by C. sinensis was 55.2% during 5 years and 5 months. Infection rate by M. yokogawai was 3.2%. This village was an endemic focus of clonorchiasis occurring reinfection high.
