[Epidemiology of hepatitis A and B and yellow fever in Zaire].

In a sero-epidemiological study, clinically healthy persons from a rural area of Zaire were tested for antibodies against hepatitis A, B and yellow fever. There was a high prevalence of antibodies to hepatitis A-virus in early life: 90% of all children at the age of ten had antibodies in their sera. Similarly up to the age of 19 years almost 90% of all persons investigated were positive for hepatitis B (anti-HBc). The incidence of the hepatitis B-surface antigen in all ages was high. According to the method used, it totalled to 21% (capillary blood) or 32% (serum specimens). All these persons were asymptomatic HBsAg carriers. A carrier-rate of 20-30% is extremely high; it has been reported only in a few studies in tropical countries. 138 serum specimens from all age groups were tested for antibodies to yellow fever virus; 59 of them (43,4%) were positive. None of these persons reported a history of yellow fever; evidently they had undergone subclinical infections. Our findings show that yellow fever still is endemic in Central Africa. It may be concluded that all persons visiting Central Africa should be vaccinated against hepatitis A (passive prophylaxis), yellow fever and, if possible, against hepatitis B.