The multiple aetiology of viral hepatitis.

Infectious hepatitis is epidemiologically and immunologically distinct from serum hepatitis. The Australia antigen is related more specifically to serum hepatitis. The possible role of coronavirus-and paramyxovirus-like particles in the aetiology of some infections of the liver in man and in marmosets inoculated with human infectious hepatitis material is discussed and the difficulties in the interpretation of the currently available data are emphasized. The recent studies in Melbourne of a faecal antigen found in some patients with infectious hepatitis and the discovery of an antiserum in Milan which reacted with an antigen associated with epidemic hepatitis are discussed. Mention is made of the recent isolation in Detroit-6 cells of virus-like particles from patients with infectious hepatitis. It is concluded that viral hepatitis is an infection of multiple aetiology and that the successful cultivation in vitro of the agent or agents of hepatitis remains the outstanding and most urgent problem.