Increasing prevalence of HIV-1 subtype A in Greece: estimating epidemic history and origin.
Paraskevis D., Magiorkinis E., Magiorkinis G., Sypsa V., Paparizos V., Lazanas M., Gargalianos P., Antoniadou A., Panos G., Chrysos G., Sambatakou H., Karafoulidou A., Skoutelis A., Kordossis T., Koratzanis G., Theodoridou M., Daikos GL., Nikolopoulos G., Pybus OG., Hatzakis A.
BACKGROUND: In North America and Europe, human immunodeficiency virus (HIV)-1 infection has typically been dominated by subtype B transmission. More recently, however, non-B subtypes have been increasingly reported in Europe. METHODS: We analyzed 1158 HIV-1-infected individuals in Greece by DNA sequencing and phylogenetic analyses of protease and partial reverse-transcriptase regions. RESULTS: We found that the prevalence of non-B subtypes has increased over time and that this significant trend can be mainly attributed to subtype A, which eventually surpassed subtype B in prevalence in 2004 (42% and 33%, respectively). Multivariate analysis revealed that the year of HIV diagnosis was independently associated with subtype A infection (odds ratio for being infected with subtype A for a 10-year increase in the time period of diagnosis, 2.09 [95% confidence interval, 1.36-3.24]; P<.001). Phylogenetic analysis revealed that the subtype A epidemic in Greece is the result of a single founder event. The date of the most recent common ancestor of the subtype A in Greece was estimated to be 1977.9 (95% highest posterior density interval, 1973.7-1981.9). CONCLUSIONS: Subtype A circulates among the long-term residents of Greece. This is in contrast to the situation in most European countries, in which infection with non-B genetic forms is associated either with being an immigrant or heterosexual or with intravenous drug use.