PREVALENCE AND RISK-FACTORS FOR HTLV-II INFECTION IN 913 INJECTING DRUG-USERS IN STOCKHOLM, 1994

The prevalence and risk factors for acquisition of human T-cell lympho tropic virus type I and II (HTLV-I and II) were investigated in a pros pective study of 913 injecting drug users (IDUs) in Stockholm in 1994. Epidemiologic data were recorded, and blood samples were tested for a ntibodies against HTLV-I and HTLV-II; human immunodeficiency virus (HI V) types 1 and 2; and hepatitis A (HAV), B (HBV), C (HCV), and D (HDV) . Positive serologic results for HTLV were confirmed by Western blot ( WE) and polymerase chain reaction (PCR). Of the 905 participants with conclusive HTLV-II status, 29 (3.2%) were HTLV-LT positive, and all bu t three were of Nordic descent. None was HTLV-I infected. One person w as infected as early as 1981, before HIV had reached the IDU populatio n in Sweden. The prevalence of HTLV-II infection was 12% among HIV-1-s eropositive and 1.8% among HIV-1-seronegative participants. The overal l seroprevalences were 14% for HIV-1, 0% for HIV-2, 41% for HAV, 75% f or HBV, 92% for HCV, and 8% for HDV. Although amphetamine has been the main injecting drug in Sweden for several decades, heroin abuse combi ned with a debut of injecting drugs before 1975 was identified as the most important risk factor associated with HTLV-II infection. HAV and HIV seropositivity were also independent risk factors.