Mussel-associated viral hepatitis, type A: serological confirmation.

7 members of a family of 14 developed acute viral hepatitis approximately one month after a family outing. Epidemiological investigation incriminated incompletely cooked mussels (Mytilus edulis) as the vehicle of infection and revealed a statistically significant difference in attack-rates between mussel-ingesters (70%) and non-ingesters (0%) (P=0-035). The aetiological role of hepatitis-A virus, suspected on epidemiological grounds, was serologically confirmed by the demonstration of rises in titres of serum-antibody to hepatitis-A antigen (serologically related to the MS-1 strain of hepatitis-A virus), determined by immune adherence haemagglutination.