[Epidemiology of hepatitis--Canton of Zurich and environs, 1976].

338 consecutive patients with acute viral hepatitis occurring in 1976 were analyzed and the data compared with similar studies from 1973 and 1974. 56% of the patients suffered from hepatitis B and the others had "non B" hepatitis. 44% were between 15 and 29 years old and 47% were women. In 43% of patients "administration and consumption of medical measures" were thought to be responsible for the viral transmission and in 24% foreign travel, while in 16% contact with hepatitis patients was suspected to be relevant. Clusters of hepatitis (more than 3 linked cases) occurred in only 3 instances (common travel abraod) involving 16 patients. While 73% of the patients with hepatitis thought to be the consequence of medical measures had hepatitis B, this was the case only in 13% of individuals in whom the disease occurred after trips to southern countries. 146 patients under hemodialysis and 78 staff members of five different hemodilaysis centers were tested for HBS-antigen and corresponding antibodies at intervals of 1-2 months. 57 individuals had signs of ongoing or past infection with hepatitis virus B at the beginning of 1976 while another 52 individuals were newly infected in the course of the year. The estimated risk of acquiring hepatitis was highest for drug addicts (15 per 1000 per year), followed by surgical staff (3-5) and travellers to "high risk" countries (4). Reasonable prophylactic measures to limit the circulation of hepatitis virus in the surveyed population are discussed.