Molecular epidemiology of HIV-1 subtype A in former Soviet Union countries

Abstract

While in other parts of the world it is on decline, incidence of HIV infection continues to rise in the former Soviet Union (FSU) countries. The present study was conducted to investigate the patterns and modes of HIV transmission in FSU countries. We performed phylogenetic analysis of publicly available 2705 HIV-1 subtype A pol sequences from thirteen FSU countries: Armenia, Azerbaijan, Belarus, Estonia, Georgia, Kazakhstan, Kyrgyzstan, Latvia, Lithuania, Moldova, Russia, Ukraine and Uzbekistan. Our analysis showed that the clusters from FSU countries were intermixed, indicating a possible role of transmigration in HIV transmission. Injection drug use was found to be the most frequent mode of transmission, while the clusters from PWID and heterosexual transmission were intermixed, indicating bridging of HIV infection across populations. To control the expanding HIV epidemic in this region, harm reduction strategies should be focused on three modes of transmission, namely, cross-border migration, injection drug use and heterosexual.

Fig 1. Phylogenetic networks of HIV subtype A in FSU countries.

Analysis was performed by Maximum Likelihood (ML) method. A stretch of HIV pol sequence corresponding to HBX2 nucleotide 2748–3244 was used for this analysis, representing sequences from Armenia, Azerbaijan, Belarus, Estonia, Georgia, Kazakhstan, Kyrgyzstan, Latvia, Lithuania, Moldova, Russia, Ukraine and Uzbekistan, with (A) or without (B) Russia, represented by, respectively, yellow green, orange, green, deep pink, medium purple, blue, yellow, teal, hot pink, brown, light pink, red, and sky blue colored branches. The branches coded grey represent 34 outgroup non-subtype A reference sequences that were used to root the tree. C) Relationship between the clusters in trees A and B is indicated. Bootstrapped versions of trees A and B are provided as supplemental files labelled as, respectively, S1A and S1B Fig.

Fig 2. Analysis of HIV transmission among high risk groups in FSU countries.

A) HIV-1 subtype A sequences from FSU countries were analyzed for high risk behavior. Only sequences with recorded high-risk labels were included in this analysis. Risk behavior information for each sequence was obtained from HIV Los Alamos Database. Red, orange, yellow, forest green, blue, turquoise, purple, brown, light pink, lime, and grey branches indicate, respectively, heterosexual, sexual transmission (unspecified type), MSM, mother-to-child, PWID, blood transfusion, homosexual, sex worker, bisexual, nosocomial, and reference sequences. B) To analyze risk behavior in the context of location, branches in the tree in 2A were re-colored based on country of origin (left), and the two trees were juxtaposed. Color key for the tree on the left is the same as that for Fig 1. Bootstrap values between 50–70 and ≤70 are shown, respectively, by red and black dots. For easy analysis, in the supplemental S2A Fig, clusters shown in Fig 2A have been magnified.