HIV Type 1 Genetic Diversity in Silesia, Poland: A Retrospective Analysis

To characterize the genetic diversity of HIV-1 strains circulating among patients with different transmission risk behaviors in Silesia, Poland, from the origin of the epidemic to the year 2004, we have sequenced and analyzed the p24 coding region of the gag gene and part of the pol gene covering the first 256 codons for the reverse transcriptase (RT). The proviral DNA was obtained from the 101 HIV-1-infected patients, 80 of whom (79.2%) were intravenous drug users (IDUs) and 21 of whom (20.8%) reported sexual transmission risk practices (STs) with 11 (10.9%) being heterosexuals and 10 (9.9%) being homosexual men, which corresponds to the population's epidemiological data. All of the investigated viral sequences were classified as HIV-1 subtype B with low genetic heterogeneity. There was an association between HIV-1 genetic diversity and the risk of virus transmission in the investigated population. The mean nucleotide distances were significantly lower among sequences derived from IDUs than among sequences obtained from STs. Additionally, strains present among IDUs, as opposed to viruses circulating among STs, were genetically more distinct from HIV-1 subtype B strains found in other populations worldwide. Our findings that HIV-1 strains circulating among IDUs were closely related to each other, but were distinct from viruses prevalent in other geographic regions, allow further tracing of the spread of these strains.