Sexual transmission of hepatitis C virus and HIV-1 infection in female intravenous drug users.

We examined the relationship between the presence of antibody to HCV and sexually transmitted diseases in 151 female, intravenous drug users aged 17-43 years. Anti-HCV was present in 49 of 66 HIV-1-negative women (74.2%), and 63 of 85 HIV-1-positive women (74.1%). Anti-HCV seropositivity was significantly related to sexually transmitted infections (Ureaplasma urealyticum infections excluded) in HIV-1-seronegative women, but not in HIV-1-positive women. Also, in HIV-1-negative subjects. Trichomonas vaginalis infections (and infections with M. hominis) were significantly related to anti-HCV seropositivity, and a positive relation between the number of sexual partners and the presence of anti-HCV was demonstrated. In HIV-1-positive subjects a shared use of needles and syringes was more likely, and an increased parenteral exposure to HCV may decrease the relative contribution by sexual transmission. However, in HIV-1-negative subjects, sexual transmission of HCV appears to be both a possible and important means of transmission.