Introduction of HIV type 1 non-B subtypes into Eastern Andalusia through immigration

A study of the distribution of HIV-1 subtypes in the native and immigrant populations of Eastern Andalusia (Southern Spain) was conducted to determine any changes between 1983 and 2001 and to identify antiretroviral resistance mutations in non-B subtype strains among the immigrant population. The study included 111 native patients from Eastern Andalusia: 94 infected with HIV before 1996 and 17 infected since 1996. A parallel study was conducted on 26 HIV-positive immigrants from Africa. Subtyping was done with the heteroduplex mobility assay. Resistance mutations were determined by line probe assay. A total of 137 patients were studied: 9.2% had subtype A (n = 12), 80.8% subtype B (n = 105), and 1.5% subtype C (n = 2). Among the Eastern Andalusia population infected before 1996, 10.9% had non-B subtypes, compared with 23.5% of those infected after that year. The greatest percentage of non-B subtypes (52.4%) was found among the immigrant population. Resistance mutation K70R was detected in one of the six immigrants with non-B subtype and M41L in another. There has been a slight increase in the diversity of HIV-1 subtypes in Eastern Andalusia over the past few years, possibly influenced by non-B subtypes introduced by immigrants from sub-Saharan Africa.