A specific complement-fixation test for human hepatitis a employing CR326 virus antigen. Diagnosis and epidemiology.

A specific diagnostic complement-fixation test for hepatitis A antibody in human serum was described employing livers of marmosets infected with CR326 strain human hepatitis A virus. Persons with hepatitis A, but not hepatitis B, developed hepatitis A CF antibody shortly after the onset of illness and this persisted thereafter. Good agreement was noted in the development of CF and neutralizing antibodies in hepatitis A cases. Hepatitis A was shown to occur in a person with hepatitis B antigenemia and hepatitis B occurred in persons with hepatitis A antibody. Most persons with hepatitis A who were tested, but none of those with hepatitis B, developed increased anticomplementary activity in their sera at the time of onset of illness. At least one patient with hepatitis A developed antibody against normal liver that persisted. The possible inplications of this in relation to pathogenesis and to non-specific diagnostic tests in hepatitis were discussed. A limited epidemiologic study of a family outbreak of hepatitis in Costa Rica and of a group of young adults in our epidemic country acquire their infections at an early age and are immune thereafter; persons in areas of relatively low incidence may proceed into adulthood without experience with hepatitis A. The CF test should provide an excellent tool for diagnosis and for epidemiologic investigation of hepatitis A and should be of considerable value to detect hepatitis A virus in attempts to propagate the virus in cell culture.