Phylogeographic reconstruction of HIV type 1B in Montenegro and the Balkan region.

Human immunodeficiency virus (HIV) is one of the most genetically variable human viruses as it is characterized by high rates of mutation, viral replication, and recombination. Phylodynamics is a powerful means of describing the behavior of an infection as a combination of evolutionary and ecological processes. Only a few studies of HIV-1 molecular epidemiology have so far been carried out in the Balkans. In this study, we used Bayesian methods to reconstruct the phylogeography and phylodynamics of HIV-1B in Montenegro and some other Balkan countries on the basis of pol gene sequences retrieved from a public database. The phylogenetic analysis showed that 43% of the isolates grouped in accordance with their geographic area, whereas the majority were interspersed in the tree, thus confirming the multiple introductions of HIV-1B in the Balkans. The Bayesian phylogeographic analysis suggested that HIV-1B entered the Balkans in the early 1970s probably through Greece and other Mediterranean tourist/travel destinations (such as Slovenia). Other Balkan countries, such as Bulgaria and Serbia, may have played an important role in spreading the infection to the entire Eastern Mediterranean area, and possibly to Northeast Europe. This suggests that the Balkans may have played a role as a "gateway" between Western and Eastern Europe.