Prevalence of HIV-1 non-B subtypes, syphilis, HTLV, and hepatitis B and C viruses among immigrant sex workers in Madrid, Spain.

Sexually transmitted disease (STD) remains a major public health challenge in developed countries, exacerbated by the advent of the HIV epidemic. The objectives of this study were to assess the prevalence of serological markers of syphilis, HIV-1/2, HTLV-I/II, HBV, and HCV infections among immigrant sex workers in Madrid, Spain and to characterize the HIV-1 variants in seropositive individuals. Sera from 762 immigrant commercial sex workers (75.3% from sub-Saharan Africa, 18.2% from South America, and 6.4% from Eastern Europe) were collected between 1998 and 2003 in Madrid and examined. Antibody detection was performed by screening assays (RPR, ELISAs) and confirmed by FTA-Abs, LIAs and Western-blot tests. HIV-1 subtyping was carried out by phylogenetic analyses of the protease and envelope genes. Antibodies to HIV-1 were found in 5.2%, while 3.5% tested positive for HBsAg, 3% for syphilis antibodies, 0.8% for HCV antibodies, and 0.2% for HTLV-I antibodies. None were reactive for HIV-2 or HTLV-II antibodies. HIV-1 seroprevalence among Africans and Ecuadorians was 4.5 and 10.9%, respectively. All HIV-1 seropositive Ecuadorians were transsexual men, and 28.6% had active syphilis infection. Up to 80% of HIV-1 positive specimens were characterized as non-B subtypes, with subtypes G, A, and G/A recombinants being the most frequent among African individuals. In contrast, South Americans with HIV-1 infection carried exclusively subtype B variants. A relatively high proportion of immigrant sex workers in Madrid were infected with HIV-1 and syphilis, whereas infections with hepatitis viruses or HTLV were uncommon.