Evidence for continuing cross-species transmission of SIVsmm to humans: characterization of a new HIV-2 lineage in rural Côte d'Ivoire

Abstract

HIV types 1 and 2 (HIV-1 and HIV-2) are the result of multiple cross-species transmissions of their simian counterparts (SIVs) to humans. We studied whether new SIVs lineages have been transmitted to humans in rural Côte d'Ivoire and identified a novel HIV-2 variant (HIV-2-07IC-TNP03) not related to any of the previously defined HIV-2 groups. This finding shows that sooty mangabey viruses continue to be transmitted to humans, causing new zoonotic outbreaks.

Fig. 1. Phylogenetic relationships of the new HIV-2 strains (HIV-2-06IC-TNP02, HIV-2-07IC-TNP01 and HIV-2-07IC-TNP03) and the new SIVsmm753 to previously characterized SIVsmm and HIV-2 strains in gag (180 amino acids) (a) and env (gp41, 132 amino acids) (b) regions

SIVsmm from Côte d’Ivoire is highlighted in blue, SIVsmm from Liberia and Sierra Leone in black and SIVsmm from captive mangabeys in the US in italic font. HIV-2 strains are highlighted in red. The new HIV-2 and SIVsmm strains from this study are boxed in red and blue, respectively. The trees were inferred with maximum likelihood (ML) methods using PHYML [18]. Appropriate amino acids substitution models were selected for each data set using MEGA5. Asterisks on branches represent bootstrap values more than 70% from 1000 pseudo-replicates. Scale bars represent substitutions per site. Trees were also inferred with Bayesian methods and confirmed topologies of maximum likelihood methods (data not shown).