Spreading of HIV-1 subtype G and envB/gagG recombinant strains among injecting ...

• Author(s): Esteves, A ; Parreira, R ; Piedade, J ; Venenno, T ; Franco, M ; Sousa, JG ; Patrício, L ; Brum, P ; Costa, A ; Canas-Ferreira, W
• Date: 2003
• Persistent ID: http://hdl.handle.net/10400.10/845
• Origin: Repositório do Hospital Prof. Doutor Fernando Fonseca
• Subject(s): HIV infections; Substance Abuse; Epidemiology; Portugal
• Document Type: Article
• Language: English

Description

We have evaluated the genetic diversity of HIV-1 strains infecting injecting drug users (IDUs) in Lisbon, Portugal. Heteroduplex mobility assay and/or phylogenetic analysis revealed that env (C2V3C3 or gp41) subtype B is present in 63.7% of the 135 viral samples studied, followed by subtypes G (23.7%), A (6.7%), F (5.2%), and D (0.7%). Similar analysis of gag (p24/p7) performed on 91 of the specimens demonstrated that 49.5% of the infections were caused by subtype G viruses; other gag subtypes identified were B (39.5%), F (3.3%), A and D (1.1.% each), and the recombinant circulating form CRF02_AG (5.5%). Discordant env/gag sub-types were detected in 34.1% of the strains and may reflect the presence of dual infections and/or recombinant viruses. The presumptive B/G recombinant form was highly predominant (21 of 31). The genetic pattern of HIV-1 subtype B and G strains is suggestive of multiple introductions and recombination episodes and of a longstanding presence of both subtypes in the country. C2V3C3 amino acid sequences from IDU-derived subtype G viruses presented highly significant signatures, which distinguish the variants from this transmission group. The unusually high prevalence of subtype G sequences (34.1%), independent of the geographic origin of the infected individuals, makes this IDU HIV-1 epidemic unique.