Hepatitis B transmission within families: potential importance of saliva as a vehicle of spread.

We report a family, extensively affected by hepatitis B virus (HBV), in whom sexual or vertical transmission is unlikely to account entirely for the intra-family clustering of the virus. HBV-DNA was detected in saliva in one family member and we suggest that spread by salivary transmission could account for at least some of the intra-family infection and could contribute to the "inapparent parenteral" spread of hepatitis B.