An HIV type 2 case series in Italy: a phylogenetic analysis.

In recent years, the increase of migration from countries where human immunodeficiency virus type 2 (HIV-2) is endemic to industrialized countries has facilitated the spread of the virus in individuals previously unexposed to this threat. In this report, we performed a phylogenetic analysis on pol and env sequences of HIV-2 strains identified in foreigners and native citizens to trace the origin of infection. All but one of the 17 pol gene sequences were classified as group A. HIV-2 strains were aggregated in several clusters depending by the country of origin and/or infection. One patient (1AA) was classified as being infected with a recombinant between HIV-2 group A and HIV-2 group B, because the pol gene sequence was clearly in the group A, but an env V3 region sequence from this patient was more similar to group B viruses. Therefore, it is urgent to strengthen the surveillance and use adequate molecular virological tools to diagnose and monitor HIV-2 infection.