Massive Sero–epidemiological Survey of Hepatitis C Virus: Clustering of Carriers on the Southwest Coast of Tsushima, Japan

We conducted a mass screening survey for anti–hepatitis C virus antibody (anti–HCV–Ab) among 1,009 inhabitants, 341 males and 668 females, older than 40 years, in south Tsushima in 1989. The overall positive rate for anti–HCV–Ab was 2.3% (2.9% in males and 1.9% in females). The positive rate for anti–HCV–Ab among people with histories of blood transfusions was 14.8% (8/54), which was higher than that (1.6%, 15/955) in people without blood transfusions (P < 0.001). The positive rate (15.1%, 8/53) in people with an elevated level of glutamic oxalacetic transaminase (GOT, >41 U/ liter) or glutamic pyruvic transaminase (GPT, >36 U/liter) was significantly higher than that (1.6%, 15/956) for people with normal values of GOT and GPT (P < 0.001). The most interesting finding was that the anti–HCV–Ab positives without histories of blood transfusions were clustered in a few villages located in the southwestern coastal areas of Tsushima, where the positive rate of 3.7% (13/355) was significantly higher (P < 0.001) than that of 0.3% (2/600) in other villages.