Blaise Bikandou

Genetic subtypes of HIV type 1 in Republic of Congo.

To assess the molecular epidemiology of HIV-1 in Republic of Congo (Congo), we investigated 29 HIV-1s obtained from 82 Congolese AIDS and ARC patients in 1996 and 1997. Part of the env region including the V3 loop was phylogenetically analyzed. The genotypes observed were varied: of 29 specimens, 12 (41 %) were subtype A, 1 (3%) was subtype D, 6 (21%) were subtype G, 6 (21%) were subtype H, 2 (7%) were subtype J, and 2 (7%) could not be classified as any known subtypes (U, unclassified). The heterogeneous profile of HIV-1 infection was different from the profiles of neighboring Central African countries. These data show that subtypes G and H as well as subtype A were circulating with high prevalence. The fact that new genetic subtypes (J and U) are circulating indicates a need for a greater surveillance for these subtypes both in Congo as well as in other parts of the world.

Natural Infection of Wild-Born Mandrills (Mandrillus sphinx) with Two Different Types of Simian Immunodeficiency Virus

We found a novel primate lentivirus in mandrill (Mandrillus sphinx). To clarify the evolutionary relationships and transmission patterns of human/simian immunodeficiency virus (HIV/SIV), we screened blood samples from 30 wild-born healthy Cameroonian mandrills. Five (16.7%) of them were seropositive for SIV. Three SIV strains were isolated from the five seropositive mandrills by cocultivation of their peripheral blood mononuclear cells (PBMCs) with PBMCs of rhesus macaques, a human T cell line (M8166), and/or a cynomolgus macaque T cell line (HSC-F). One of the newly isolated SIV strains was intravenously inoculated into two rhesus macaques and resulted in chronic infection. In the SIV-infected macaques at 45 weeks after inoculation, we observed a mild decline in the number of peripheral CD4(+) lymphocytes, lymphadenopathy, and blastic follicular dendritic cells with mild follicular hyperplasia in the peripheral lymph nodes. A phylogenetic analysis based on the pol sequence showed that the newly found SIVs from Cameroonian mandrills did not cluster with SIVmndGB1, which is the former representative strain of SIVmnd. The SIVmnds from Cameroon formed a new, independent lineage that branched before the root of the HIV-1/SIVcpz lineage with 996 of 1000 bootstrap replications. They clustered host specifically, and exhibited about 16.9% diversity at the level of nucleotide sequence among Cameroonian SIVmnd strains. These results indicate that the SIVmnds isolated in Cameroon are a novel type of SIVmnd and have infected Cameroonian mandrills for a long time. We therefore designated the Cameroonian SIVmnd as SIVmnd type 2 and redesignated SIVmndGB1 as SIVmnd type 1. To date, M. sphinx is the only primate species other than humans that is naturally infected with two different types of SIV.

African origin of GB virus C/hepatitis G virus1

Ninety‐four GB virus C/hepatitis G virus (GBV‐C/HGV) RNA‐positive serum samples were obtained from all over the world. We found that all 15 GBV‐C/HGV isolates from the Pygmies and the Bantu in the Central African region had a 12‐amino acid indel (i.e. insertion or deletion) in the non‐structural protein (NS) 5A region. Phylogenetic analyses of the NS5A region, using GBV‐A as an outgroup, showed that these 15 isolates had diverged from the common ancestor much earlier than the remaining isolates, indicating an African origin of GBV‐C/HGV.

Natural infection of chimpanzees with new lentiviruses related to HIV-1/SIVcpz

Abstract: To determine newly identified lentiviruses, termed simian immunodeficiency virus (SIV)cpz97CG4 and SIVcpz97CG6, from two wild‐captured juvenile brother chimpanzees in the Republic of Congo, subgenomic pol (integrase, 288 bp), 5′tat/rev‐env C1 (including vpu, 354 bp) and env (C2‐C4, 544 bp) gene fragments were amplified and sequenced. The analysis revealed significantly discordant phylogenetic positions of SIVcpz97CG in each genomic region. In the trees derived from partial env sequences (V3), both SIVcpz strains clustered in human immunodeficiency virus type 1 (HIV‐1) subtype A. However, in the trees derived from partial pol (integrase) and 5′tat/rev‐env C1 (including vpu) sequences, they clustered independently from any of the known HIV‐1 subtypes. Especially, in the 5′tat/rev‐vpu tree, they branched before the root of HIV‐1 group M. These findings suggest that these Congolese SIVcpz genomes are mosaic, probably due to a recombinational event in the recent past, and it provides evidence for a rather recently occurring cross‐species transmission between humans and chimpanzees.