The natural history of infectious hepatitis

Since 1956 approximately 700 cases of infectious hepatitis with jaundice were observed at Willowbrook State School, an institution for mentally defective children. This endemic situation provided an ideal setting for the study of the natural history of the disease. The incubation period of infectious hepatitis acquired either parenterally or orally ranged between thirty-five and fifty days. Virus was detected in stools and blood during the incubation period and early in the course of the disease. Stools collected at the following intervals were shown to be infective: on the twenty-fifth day of the incubation period (two weeks before onset of jaundice) and on the first to eighth day after onset of jaundice. Stools collected on the eleventh day of the incubation period and on the nineteenth to thirty-third day after onset of jaundice were not shown to be infective. Viremia was detected on the twenty-fifth day of the incubation period, three to seven days before and three days after onset of jaundice. Viremia was not detected on the eighteenth day of the incubation period. A parenteral inoculation of 0.025 ml. of a serum pool was highly infective, inducing hepatitis with jaundice in six of nine subjects. The demonstration of viremia in a case of inapparent infectious hepatitis provided proof that infection can occur without overt signs or symptoms of disease. Second attacks were observed in 4.6 per cent of 697 cases of infectious hepatitis with jaundice. In an institution in which infectious hepatitis was endemic, the administration of gamma globulin, 0.06 ml. per pound of body weight, suppressed jaundice for a five-month period but it did not prevent an icteric infection.