Seroepidemiologic surveys of schoolchildren in Arachova and Anthili, Greece, were undertaken to study the possible role of mosquitoes in transmission of hepatitis B virus infection. The two areas are comparable in most known characteristics that may contribute to the spread of the disease, but Anthili has a much higher mosquito density. The overall prevalence of hepatitis B antigen was 2.7% in the Anthili population and 0.9% in the Arachova population. Antibody to hepatitis B virus was detected in a significantly higher frequency in the Anthili (20.5%) than in the Arachova (5.1%) population. These findings give further support to the previously suggested hypothesis that mosquitoes may play a role in the transmission of hepatitis B virus
