THE EPIDEMIOLOGY OF HEPATITIS B INFECTIONS IN AFRICA: RESULTS OF A PILOT SURVEY IN THE REPUBLIC OF SENEGAL

Abstract

A pilot survey conducted in Senegal revealed that 13% of 1430 children and 9.7% of 2221 male adults were carriers of hepatitis B antigen (HB Ag). All but a few of them were found to be persistent carriers. The prevalence of HB Ag was closely associated with age; as many as 11.7% of infants and 16% of children between 7–8 years of age carried antigen, as compared with 4.5% of those older than 39 years. In children, the HB Ag prevalence was also sex-related, being significantly higher among males than females. During a 6-month period, 2.2–2.6% of the tested children newly acquired the antigen. HB antibody was detected in 35.2% of adults negative for HB Ag. In those positive for HB antibody, the passive hemagglutination titers were found to be similar to those found in patients with Down's syndrome, but much lower than among other comparable sex-age groups in the USA. Possible mechanisms which may account for the high frequency of the HB Ag carrier state and of HB infection in the tropics are reviewed.