Epidemiology of hepatitis B virus infection in South African Chinese.

The authors determined the age-specific prevalence of hepatitis B virus markers in 1,408 Chinese who resided in South Africa in 1983-1985. The small South African Chinese community consists of original Chinese settlers, almost all of whom migrated from the hepatitis B virus endemic mainland China province of Guangdong, and their South African-born descendants. The Chinese live among the white South African community, which has a very low hepatitis B virus carrier rate. The overall hepatitis B virus carrier rate was 5.3%, and the carrier rate was highest in age group 30-39 years (11.9%) and significantly lower in children aged 1-9 and 10-19 years (2.4% and 2.0%, respectively). Overall infection rates increased progressively with increasing age, starting at about 10% in the children aged 1-19 years and reaching 50% in adults aged 60-69 years. Among carrier children, 89% had carrier mothers, and all of the latter were also hepatitis e antigen (HBeAg)-positive. The prevalence of hepatitis B virus carriers in South African Chinese women of child-bearing age was 6.1%, and 41.9% of these carriers were HBeAg-positive. The age-specific prevalence of hepatitis B virus markers among South African Chinese is appreciably lower than that of Chinese in southeastern China, who have carrier rates of 15-20% with a peak in childhood. The prevalence of hepatitis B virus infection appears to be decreasing in South African Chinese, probably because improved hygienic and socioeconomic circumstances, in comparison with those in Guangdong, have resulted in less horizontal transmission of the virus. A diminishing pool of carriers is maintained by perinatal maternal-infant infection.