Risk factors for transmission of hepatitis B virus to Gambian children [published erratum appears in Lancet 1990 Dec 22-29;336(8730):1596] Risk factors for hepatitis B virus transmission were examined in 973 Gambian children aged 6 months to 5 years. 33% had evidence of infection with hepatitis B virus and a third of these were carriers. A significant association was found between infection and tropical ulcer scars, and between e antigenaemia and the presence of bedbugs in each child's bed. There was no association between infection and traditional scarring, circumcision, or injections. Skin disease and arthropods are the two most likely modes of transmission of hepatitis B virus between children in West Africa. 