Multicentre study of prevalence of HBV-associated delta infection and liver disease in drug-addicts.

To assess the epidemiological and pathogenic effects of infection with the hepatitis-B-virus (HBV)-associated delta agent in addicts who take drugs parenterally, 225 symptomless addicts from Italy and 261 addicts with HBsAg-positive hepatitis from Italy, Denmark, Switzerland, and Ireland were tested for delta antigen (delta-Ag) and its antibody (anti-delta) by radioimmunoassay. 79 liver biopsy specimens from HBsAg-positive addicts were also tested for intrahepatic delta-Ag by immunofluorescence. Anti-delta was found in 9 (27%) of 33 of the symptomless HBsAg-positive addicts, in 13 (8%) of 156 of those without HBsAg but with anti-HBs, and in none of those negative for HBV markers. The prevalence of serum delta-Ag or anti-delta among addicts with HBsAg-positive hepatitis was 64% (104/161) in Italy, 44% (8/18) in Denmark, 33% (11/33) in Switzerland, and 31% (15/49) in Ireland. 32 of the 79 (40%)liver biopsy specimens from HBsAg-positive addicts showed positive delta-Ag immunofluorescence. Delta infection occurring simultaneously with HBV infection is common and possibly a major cause of liver disease in drug addicts who receive drug parenterally. The spread of delta infection in drug-using communities is not confined to one country, and the drug habit may represent the major means by which delta agent spreads in areas of the Western world where this infection is not endemic.