Associations among HTLV-I, HTLV-II, and HIV in injecting drug users in Salvador, Brazil.

A cross-sectional study using a snowball sampling technique was performed from August 1994 to September 1996 in the Pelourinho district of Salvador Brazil to assess the prevalence of HIV HTLV-I and HTLV-II among IV drug users (IVDUs). 177 male and 39 female asymptomatic IVDUs were interviewed on demographics sex behavior and drug use then tested for infection using ELISA and Western blot. 49.5% were aged 21-34 years. HTLV-I/II coinfections were confirmed by nested polymerase chain reaction. 55 (25.5%) subjects were infected with HTLV-I 19 (8.8%) with HTLV-II and 107 (49.5%) with HIV-1. HTLV-I was identified in 72.4% of HTLV-positive IVDUs. The prevalence of coinfection was 22.2% and 10.6% for HTLV-I/HIV-1 and HTLV-II/HIV-1 respectively while 2 men aged 16 and 44 years were infected with HIV-1 HTLV-I and HTLV-II. No subject displayed any serological evidence of syphilis. Univariate analysis found that being female and aged 35-66 years were associated with HTLV-I infection but not with HTLV-II infection. HIV-1 seropositivity and syphilis were strong risk factors for HTLV-I infection.