An epidemiological study on chronicity and incidence of hepatocellular carcinoma in the sequence of epidemic hepatitis

: From November 1951 to 1954, 416 patients in Kumayama Town, Okayama Prefecture, suffered from epidemic hepatitis, so-called "Kumayama Hepatitis". The mortality rate was 13.98% in the first one year, and the rate of progress to chronic hepatitis after 10 years was 24.6%. In the present study surveyed in 1991, 720 residents in this area had 13.6% positive anti-HCV (C100-3), significantly higher than in control areas. The rate of positive anti-HBs and abnormal liver functions in the subjects with positive anti-HCV was 42.9% and 40.8%, respectively. In 29 patients with clinically typical "Kumayama Hepatitis", the positivity rate of anti-HA IgG, anti-HBs, and anti-HCV, and the prevalence of abnormal liver function was 82.8%, 41.4%, 34.5%, and 10.3%, respectively. In conclusion, it is suggested that the hepatitis epidemic in Kumayama Town was caused by HAV and superinfected by HCV and/or HBV, then its clinical manifestations became complicated.