Serological markers of hepatitis B virus and certain other viruses in the population of eastern Caprivi, Namibia.

Serum samples from 475 male and 420 female subjects from the population of eastern Caprivi, the north-easternmost territory in northern Namibia, were examined for the presence of hepatitis B surface antigen (HBsAg), antibodies to HBsAg (anti-HBs) and hepatitis B core antigen (anti-HBc). There appeared to be a rapid acquisition of antibodies to the different markers in childhood, reaching maximum values in the 20-24 year age group. The prevalence rate for all markers was lower in eastern Caprivi than in Kavango, an area 180 km to the west. The reason for these differences is unclear. It is postulated that the hut tampan tick (Ornithodoros moubata), which has previously been shown to be implicated in the transmission of hepatitis B virus in Kavango, is more common in the latter territory than in eastern Caprivi. Huts in eastern Caprivi are usually better constructed than in Kavango, where reeds are commonly used as building material. Tampans lodge between the reeds and are more difficult to eradicate. West Nile virus was the most common of the arboviruses found in our sero-prevalence studies.