Objective: To define the epidemiology and clinical manifestations of hepatitis D virus infection in an institutionalized population.
Design: A case-control study of hepatitis B carriers with and without serologic evidence of hepatitis D virus infection. Demographic, institutional, and medical data were obtained through questionnaires and chart review. Clinical status was assessed by liver function assays.
Setting: Thirteen Illinois state facilities for the developmentally disabled.
Participants: Clients (238) who were hepatitis B carriers.
Results: Antibody to hepatitis D virus (anti-HDV) was detected in 71 of 238 (30%) hepatitis B carriers. Nine of thirteen facilities housed positive clients. Previous residence at one facility, designated B, was the strongest correlate of anti-HDV positivity; 85% of positive persons had lived there compared with 16% of negative controls (odds ratio 28.3 [95% CI, 13.2 to 60.7], P < 0.001). Past hepatitis episodes were more common among anti-HDV-positive clients (37% compared with 7%) (odds ratio, 7.5 [95% CI, 3.0 to 19.1], P < 0.001) and occurred mainly at facility B from 1950 to 1975. Liver function tests were infrequently abnormal among anti-HDV-positive clients.
Conclusions: Results show widespread hepatitis D virus infection in our institutionalized population and suggest that transmission occurred mainly in the past at the overcrowded facility B. The low prevalence of laboratory evidence of chronic liver disease in the anti-HDV-positive clients may be explained by increased mortality among those originally infected from 1950 to 1975.