HIV-1 circulating subtypes in Romania.

The Romanian HIV epidemic is characterized by the prevalence of a single particular HIV1 subtype, called F, a minor form, previously reported only in South America and Central Africa. Initially reported in the early '90s by serotyping studies in the large cohort of parenterally infected children, this subtype remained dominant during the following two decades, despite the continuous growth in the number of heterosexually-acquired infections in adults. A steady prevalence of F subtype was further demonstrated by genotyping and molecular epidemiology studies. This article reviews the hypothesis on the origin and the unusual steady persistence of this HIV strain and discusses the recent changes in the molecular epidemiology of the epidemic, associated to the emergence of new infection routes. Phylogenetic and phylogeography studies conducted through the epidemic seem to indicate that HIV F subtype originated in the 1950s in the Democratic Republic of Congo and was separately spread by immigration waves to Brazil, Angola and Romania. Data released at the end of 2012 report F1 subtype as the dominant HIV-1 clade in Romania in all categories of patients: recently infected or late presenters, antiretroviral- naive or heavily treated, but signal the emergence of other subtypes (B--the most frequent non-F subtype among the newly diagnosed individuals, followed by subtypes C, A and several circulating recombinant forms). In this context, it is of outmost importance to follow the spreading of new emerging subtypes in the predictable setting of new infection waves in the Romanian HIV epidemic.