[Spread of hepatitis B virus infection among family contacts of asymptomatic HBsAg carriers (author's transl)].

Family members of 34 asymptomatic HBsAg carriers were tested for different hepatitis B virus (HBV) markers. Among 67 family members tested 24 (36%) presented signs of a past or ongoing HBV-infection. Spread of HBV-infection was particularly high in those families in which the HBsAg carrier was positive for HBeAg and Dane particle-associated DNA polymerase activity. Non-parenteral "horizontal" transmission of HBV among spouses and brothers and sisters and probably parenteral vertical transmission of HBV from carrier mothers to their infants occurred in approximately the same frequency. Fathers transmitted HBV unfrequently to their offsprings. The results show that the risk to acquire a HBV-infection from an asymptomatic HBsAg carrier is closely linked to the serological findings in the HBe/anti-HBe-system of the index HBsAg carrier and not to the family relationship to the HBsAg carrier.