Genetic diversity of simian lentivirus in wild De Brazza's monkeys (Cercopithecus neglectus) in Equatorial Africa

Abstract

De Brazza's monkeys (Cercopithecus neglectus) are non-human primates (NHP) living in Equatorial Africa from South Cameroon through the Congo-Basin to Uganda. As most of the NHP living in sub-Saharan Africa, they are naturally infected with their own simian lentivirus, SIVdeb. Previous studies confirmed this infection for De Brazza's from East Cameroon and Uganda. In this report, we studied the genetic diversity of SIVdeb in De Brazza's monkeys from different geographical areas in South Cameroon and from the Democratic Republic of Congo (DRC). SIVdeb strains from east, central and western equatorial Africa form a species-specific monophyletic lineage. Phylogeographic clustering was observed among SIVdeb strains from Cameroon, the DRC and Uganda, but also among primates from distinct areas in Cameroon. These observations suggest a longstanding virus-host co-evolution. SIVdeb prevalence is high in wild De Brazza's populations and thus represents a current risk for humans exposed to these primates in central Africa.

Fig. 1.

Phylogenetic relationship of the newly derived SIVdeb strain (in red) to previously described SIVdeb viruses (blue) and other SIV lineages (black) in Gag, Pol and Env regions. The unrooted maximum-likelihood trees were inferred from protein sequence alignments. The numbers at nodes are the estimated posterior probabilities from the Bayesian method (values of 95 % and above are shown). Bars, 0.1 substitutions per site. The box shows diversity plots of concatenated protein sequences representing the extent of the genetic difference between SIVdeb04CMPF3061 and other primate lentiviruses. The y-axis indicates the distance between the viral proteins (0.1=10 % difference).

Fig. 2.

Phylogenetic tree of SIVdeb from south-east and south Cameroon, the DRC and Uganda. Maximum-likelihood trees were inferred from a partial (164 aa) Pol protein sequence alignment. The numbers on the internal branches indicate estimated posterior probabilities (only values of 95 % or greater are shown). Bar, 0.08 substitutions per site. The map on the right shows the natural range of De Brazza’s monkey in Equatorial Africa (dark) and locations of sample collection for each of the SIVdeb group represented on the phylogenetic tree.