Survey of HBag hepatitis infection in a semi-closed community.

The presentation of one individual with HBAg-positive hepatitis in a semi-closed community led to the testing of 262 intellectually-handicapped persons and staff-members and to the detection of 12 others who were HBAg-positive. Only the presenting case and one other became unwell with hepatitis. Three other HBAg-positive individuals became negative within three months, none showing clinical or biochemical evidence of hepatitis. The remaining eight persons were still HBAg-positive six months later. Four of these had biochemical abnormalities suggesting they had suffered anicteric hepatitis while the remainder, three of whom had Down's syndrome, had no such changes and are therefore considered to be carriers of the infective agent.