Transmission of non-A, non-B hepatitis

In studies conducted in the early 1950s, sera from six asymptomatic blood donors, implicated in the transmission of viral hepatitis, were inoculated into 10 to 20 volunteers each. Five of these "implicated" donor sera transmitted clinically apparent hepatitis to the recipients. The stored serum samples from these studies have been reanalyzed using serologic markers for hepatitis B virus and hepatitis A virus infection. Two of the donor sera were hepatitis B surface antigen (HBsAg)-positive, and both transmitted hepatitis B virus infection to all susceptible recipients, half of whom showing clinical symptoms. The remaining three infectious donors were HBs-Ag-negative, yet were icterogenic to 10% to 47% of recipients. Testing of serum samples from these recipients with hepatitis showed no evidence of hepatitis B virus or hepatitis A virus infection. This study and other recent evidence suggest that there is a third type of human viral hepatitis--non-A, non-B hepatitis--which is due to a transmissible agent and may well be associated with a chronic carrier state.