It was observed in the city of Salvador, State of Bahia, the highest seroprevalence of
human T cell lymphotropic virus type 1 (HTLV-I) infection in Brazil as demonstrated by
national wide blood bank surveys. In this paper, we report results of an investigation of drug
use and sexual behavior associated with HTLV-I infection among male and female injecting
drug users (IDUs) in Salvador. A cross sectional study was conducted in the Historical
District of Salvador from 1994-1996 (Projeto Brasil-Salvador) and 216 asymptomatic
IDUs were selected using the snowball contact technique. Blood samples were collected for
serological assays. Sera were screened for human immunodeficiency virus (HIV-1/2) and
HTLV-I/II antibodies by ELISA and confirmed by Western blot. The overall prevalence of
HTLV-I/II was 35.2% (76/216). The seroprevalence of HTLV-I, HTLV-II and HIV-1 was for
males 22%, 11.3% and 44.1% and for females 46.2%, 10.3% and 74.4% respectively.
HTLV-I was identified in 72.4% of HTLV positive IDUs. Variables which were significantly
associated with HTLV-I infection among males included needle sharing practices, duration of
injecting drug use, HIV-1 seropositivity and syphilis. Among women, duration of injecting
drug use and syphilis were strongly associated with HTLV-I infection. Multivariate analysis
did not change the direction of these associations. Sexual intercourse might play a more
important role in HTLV-I infection among women than in men.
