Evidence of increased risk for leishmania infantum infection among HIV-seronegative intravenous drug users from southern Spain.

To assess the prevalence of markers of Leishmania infection, 93 intravenous drug users and 77 nonusers of intravenous drugs underwent a Leishmania skin test and a serum Leishmania antibody search. All participants were human immunodeficiency virus seronegative. The Leishmania skin test was positive in 24 intravenous drug users and in 10 non-users of intravenous drugs (P=0.038). Leishmania seropositivity was detected in 3 of 11 active intravenous drug users and in 3 of 82 former drug injectors (P=0.02). Positivity in the Leishmania skin test was associated with intravenous drug use (adjusted odds ratio, 2.33; 95% confidence interval, 1.03-5.24). The prevalence of Leishmania infection markers among intravenous drug users is higher than that among controls. This suggests that this parasite spreads through the sharing of needles.