Epidemiology of acute viral hepatitis in Singapore.

A total of 194 cases of acute viral hepatitis were notified between June and December 1976. Thirty-five (22.6%) out of 155 patients were positive for HBs Ag by counter-immuno-electrophoresis. The ethnic-specific morbidity rates per 100,000 were Chinese, 9.51; Malays, 3.20; Indians, 8.30 and others, 1.13; and the age specific attack rates were high in the 15 -- 24 and 25 -- 34 age groups, being 15.05 and 15.77 per 100,000 respectively. The male to female ratio was 3.04:1. Cases were not confined to areas with poor environmental sanitation. There were very few secondary cases. Unrecognized anicteric or subclinical cases probably play an important role in the transmission of viral hepatitis in the community. The possibility of transmission of hepatitis A by contaminated food was discussed.