Delta virus infection and severe hepatitis. An epidemic in the Yucpa Indians of Venezuela.

Over a 3-year period, 149 Yucpa Indians in Venezuela developed hepatitis; 34 persons died and at least 22 developed chronic hepatitis. Children and young adults were primarily affected, especially males. Serologic testing showed that hepatitis B virus infection was highly endemic in this population, but also that 65% of patients had hepatitis B virus surface antigen (HBsAg) during or after illness. Most patients had evidence of delta-agent superinfection; 86% of HBsAg-positive patients had delta antibody, and delta antigen was found in specimens taken during autopsies on 7 of 9 patients. Serologic data suggested that most infections were due to delta superinfection of hepatitis B carriers, and that more than 60% of these infections progressed to chronic disease. Delta agent infection, and particularly delta superinfection of hepatitis B carriers, appears to be an ominous occurrence that may develop in populations among whom hepatitis B virus infection is endemic, and who have no other risk factor for delta infection.