No abstract

Limited information is available to describe the molecular epidemiology of HIV-1 in Bulgaria. To better understand the genetic diversity and the epidemiologic dynamics of HIV-1 we analyzed 125 new polymerase (pol) sequences from Bulgarians diagnosed through 2009 and 77 pol sequences available from our previous study from persons infected prior to 2007. Epidemiologic and demographic information was obtained from each participant and phylogenetic analysis was used to infer HIV-1 evolutionary histories. 120 (59.5%) persons were infected with one of five different HIV-1 subtypes (A1, B, C, F1 and H) and 63 (31.2%) persons were infected with one of six different circulating recombinant forms (CRFs; 01_AE, 02_AG, 04_cpx, 05_DF, 14_BG, and 36_cpx). We also for the first time identified infection with two different clusters of unique A-like and F-like sub-subtype variants in 12 persons (5.9%) and seven unique recombinant forms (3.5%), including a novel J/C recombinant. While subtype B was the major genotype identified and was more prevalent in MSM and increased between 2000–2005, most non-B subtypes were present in persons ≥45 years old. CRF01_AE was the most common non-B subtype and was higher in women and IDUs relative to other risk groups combined. Our results show that HIV-1 infection in Bulgaria reflects the shifting distribution of genotypes coincident with the changing epidemiology of the HIV-1 epidemic among different risk groups. Our data support increased public health interventions targeting IDUs and MSM. Furthermore, the substantial and increasing HIV-1 genetic heterogeneity, combined with fluctuating infection dynamics, highlights the importance of sustained and expanded surveillance to prevent and control HIV-1 infection in Bulgaria.

We found a low prevalence of TDR against a background of high HIV-1 genetic diversity among antiretroviral-naive patients in Bulgaria. Our results provide baseline data on TDR and support continued surveillance of high-risk populations in Bulgaria to better target treatment and prevention efforts.

In a representative nationwide study, we have determined the prevalence of hepatitis B virus (HBV) and hepatitis C virus (HCV) coinfections among HIV-positive patients diagnosed during the period 2010-2014 in Bulgaria. Despite a relatively low rate of new HIV diagnoses, the rates of hepatitis B and C coinfections among these patients fell within the upper range reported in Europe. HBsAg and HCV antibodies (Ab) were found in 10.4% and 25.6% of the tested individuals, respectively. Importantly, high rates of active hepatitis infections were confirmed by detection of HBV DNA in 51.1% and HCV RNA in 78.1% of the tested individuals. Hepatitis coinfections affected mostly high risk groups and persons with multiple risk behavior, including people who inject drugs, men who have sex with men, prisoners, and Roma people.

Human immunodeficiency virus (HIV) was originally introduced in Bulgaria through heterosexual transmission (HET) and later transferred to other vulnerable groups along with numerous more recent introductions from outside Bulgaria. To define the diversity, origins, and dynamics of the HIV-1 subtypes prevalent in HET population in Bulgaria, we applied phylogenetic and phylodynamic analyses using polymerase (pol) sequences from HET individuals to infer the spatiotemporal evolutionary history of the HIV-1 epidemic in this population in Bulgaria. High genetic diversity was found, including 13 different HIV-1 subtypes: 45.7% subtype B, 19.9% CRF01_AE, 7.5% CRF02_AG, 7.5% sub-subtypes A1 and A6, 7.1% subtype C, 5.3% subtype F1, 4.0% URFs, 1.2% CRF05_DF, 0.6% subtype G, 0.3% CRF04_cpx, 0.3% CRF29_BF, 0.3% CRF14_BG, and 0.3% subtype H. The estimated root of the subtype B in the phylogenetic tree dated back to the year 1980 largely due to multiple introductions of subtype B from outside the country. Several significant clades have been identified highlighting six different main epidemic entrances of subtype B dating from 1989 to 2007. The Bayesian skyline plot showed two different exponential growth periods starting in the 1980s to 1990 followed by a constant phase up to about 2008, with another exponential growth period from 2008 to the year 2012. The migration analysis identified dynamic pattern of gene flow and demonstrated that many HET probably acquired the infection abroad (14.6%), while only (6.6%) of non-HET were infected outside country. The phylogenetic analysis showed an intermixing between sequences from Bulgarians with sequences from other countries, suggesting different HIV introduction in this country followed by the internal spread through local transmission networks.