ABSTRACT
At least four distinct viruses causing human hepatitis have been distinguished to date on the basis of their biologic, physiochemical and antigenic characteristics (Table 12.1).
HEPATITIS A VIRUS (HAV)
Hepatitis A virus (HAV), formerly called infectious hepatitis (IH) virus or MS-I virus, most closely resembles the picornaviruses. The virus is approximately 27 nm in diameter and appears to have cubic symmetry. Degradative analysis has revealed three major polypeptides as well as the presence of a genome of linear single-stranded RNA. The polypeptides have molecular weights similar to three of the four polypeptides of enteroviruses. HAV is stable in the presence of ether at acid pH and is relatively resistant to heat. In 1969, Holmes and Deinhardt succeeded in transmitting HAV to marmoset monkeys. The subsequent detection of HA antigen (HAAg) in the serum and liver of infected marmoset monkeys, by Hilleman and associates, paved the way for the development of the current tests for hepatitis A antibody (anti-HAV).
