[Epidemiology of hepatitis D virus infection].

The hepatitis D (Delta) virus (HDV) is an incomplete RNA virus which only replicates when a hepatitis B virus (HBV) infection is present. The detection of anti-Delta virus antibodies (anti-Delta) indicates an ongoing or past infection with HDV. Anti-Delta were measured in serum samples of 939 individuals from various groups of patients and of healthy high risk individuals presenting different states of HBV infections. 636 samples were drawn in 1984 and 303 in 1980. In 1984 anti-Delta were most often detectable in healthy homosexuals (19 of 35 individuals = 54%), followed by healthy drug addicts (44 of 207 individuals = 22%), patients with acute hepatitis B (2 of 63 individuals) or with chronic hepatitis B (1 of 74 individuals), patients under hemodialysis or with renal allografts (2 of 90 individuals), and in healthy HBs-Ag positive blood donors (2 of 48 individuals). Within a given risk group of individuals anti-Delta was most often found in those with HBs-Ag, followed by those with anti-HBc alone or with anti-HBs. The prevalence of anti-Delta augmented from 7% in 1980 to 22% in 1984 in drug addicts and from 0 to 54% in homosexuals. The diagnostic testing for anti-Delta can presently be restricted to hepatitis B patients who are homosexuals or drug addicts. However, this policy might have to be changed if the epidemic situation changes. Vaccination against hepatitis B is the best prophylactic measure to inhibit the further spread of HDV infections.