RESUMO
The prevalence rates of hepatitis-B surface antigen (HGsAg) and its homologous antibody (anti-HBs) were determined in 62 patients in a leprosarium (42 tuberculoid and 20 lepromatous) and in 40 adults living near the locality. The exposure rate (HBsAg + anti-HBs) was high in both controls and patients, 72.5% and 70.9% respectively, The frequency of HBsAg was significantly higher in patients with lepromatous leprosy (40%) compared with controls (10%) (chi 2 = 5.7 p less than 0.025) but there was no difference in the prevalence rate of HBsAg between patients with lepromatous leprosy (40%) compared with those with tuberculoid leprosy (23.8%) (chi 2 = 1.7 p greater than 0.1). The exposure rate was higher in the lepromatous group (80%) compared with the tuberculoid group (59.5%) but the difference was not significant (chi 2 = 2.87 p greater than 0.05). It is concluded that the high rate of infection in patients with leprosy if not due to a peculiar genetic defect but the result of living in an environment where the virus is highly endemic. The observed significance increase in carriage of HBsAg in lepromatous leprosy is probably due to depressed cellular immune function characteristic of this group of patients. The slightly increased exposure rate to HBV of lepromatous versus the tuberculoid type of leprosy is probably due to increased opportunity for infections from repeated and prolonged stay in hospital.