[Seroprevalence of human T cell lymphotropic virus infection and associated factors of risk in blood donors of Rio Branco city, AC, Brazil (1998-2001)].

Between December 1998 and March 2001, for each HTLV-I/II seropositive blood donor (ELISA, Abbott), two HTLV-I/II seronegative blood donors were also chosen. The blood samples were re-tested by ELISA (Murex), and those seropositives were also tested by Western Blot and PCR. Of the 11, 121 blood samples, 73 (0.66%) were positives (Abbott), but only 12 (0.11%) remained positives (Murex), whereas the 146 seronegatives were confirmed, even though the concordance index between these two ELISA tests was hopeless. The Western Blot confirmed the twelve blood samples as seropositives: 8 (0.07%) HTLV-I; two (0.02%) HTLV-II and two (0.02%) indeterminate, being by PCR, one HTLV-I and the other HTLV-II. Concluding, in this Western Amazon population the HTLV-I/II seroprevalence was too low, in spite of the greater prevalence of HTLV-II expected due to a great indigenous racial mixture.