Es represent the gag sequences sampled from Cameroon in this study, while red squares represent intragene recombinant fragments in our samples. The blue squares show the new divergent branches formed by viruses sampled in this study. Sequence C.ZM.2006.ZM1464F appears to have been mis-labelled in the LANL database, and consistently groups with subtype A1. Additional file 2: Detailed phylogenetic a