PREVALENCE AND PHYLOGENETIC ANALYSIS OF HTLV-I ISOLATES IN CAMEROON, INCLUDING THOSE OF THE BAKA-PYGMY

Our previous analysis of an HTLV-I isolate (CMR229) from a Cameroonian Pygmy demonstrated that the isolate is distinct from typical HTLV-Is of the ''Central African group,'' which has a close similarity to HTLV -I-related simian viruses (STLV-I) in Africa. In this study, we analyz ed six new HTLV-Is from Cameroon consisting of three isolates from the Pygmy and three from the Bantu to examine further the genetic feature s of HTLV-I in Cameroon, especially in the Pygmy. A phylogenetic tree based on the long terminal repeats (LTR) region showed that all the ne w HTLV-Is belong to the Central African group. On the other hand, an e nv-based analysis of CMR229 confirmed the previous finding derived fro m LTR-based analysis that CMR229 has a similarity to African STLV-Is, but is distinct from the typical Central African group of HTLV-I. This suggests that multiple interspecies transmissions from non-human prim ates to humans have occurred in Central Africa, resulting in the prese nce of two distinct HTLV-I strains in this area. In addition, it seems likely that the Pygmy harbors the heterogeneous HTLV-I strains from w hich the main HTLV-I population spread into the Bantu.