Showing papers by "Nicole Vidal published in 2003"

High genetic diversity of HIV-1 strains in Chad, West Central Africa

Abstract: The genetic diversity of HIV-1 strains in Chad was documented with a total of 107 samples from patients attending the general hospital in N’Djamena the capital city of Chad. The genetic subtypes were identified in the V3–V5 env and p24 gag regions by sequence and phylogenetic tree analyses. Of the 107 strains 78 had the same subtype/CRF designation between env and gag. Four subtypes and three CRFs were found to cocirculate: subtype A 20.5%; subtype D 18.7%; CRF02_AG 13.1%; CRF11_cpx 13.1%; subtype G 3.7%; CRF01_AE 2.8%; and subtype F1 0.9%. The remaining 29 strains (27%) had discordant subtypes or CRF designations between env and gag; in 15 of these 29 strains a CRF was involved in the recombination event and 10 were subtype G in gag and subtype A in env forming a separate subcluster within subtypes G and A. Subtype D strains represent almost 20% of the HIV-1 strains circulating in Chad and form a separate subcluster in gag and env. Nearly full-length genome sequencing for two such strains (99TCD-MN011 and 99TCD-MN012) revealed that they represent nonrecombinant subtype D variants. Compared with neighboring countries the genetic subtype distribution of HIV-1 strains in Chad is unique for several reasons: lower prevalence of CRF02 high prevalence of CRF11 and subtype D and absence of CRF06. These data clearly show that subtype distribution is very heterogeneous in Africa probably the result of different founder effects. (authors)

Emergence of complex and diverse CRF02-AG/CRF06-cpx recombinant HIV type 1 strains in Niger, West Africa.

Abstract: On the basis of partial env and gag subtyping, we documented that the majority of HIV-1 strains circulating in Niger were CRF02-AG (543%) or CRF06-cpx (181%) and that 9% of the samples were possible recombinants between CRF02 and CRF06 To determine in more detail the precise structure of these viruses we sequenced the full-length genomes for three such strains (97NE-003, 00NE-036, and 00NE-095) From the bootscan and phylogenetic tree analysis it is evident that the new viruses are the result of recombination events between CRF02-AG and CRF06-cpx strains Importantly, each virus had a different complex recombinant structure with multiple breakpoints, leading to viruses with complex mosaic patterns

CRF06-cpx is the predominant HIV-1 variant in AIDS patients from Ouagadougou, the capital city of Burkina Faso.

Abstract: No data on HIV-1 genetic subtypes in Burkina Faso have yet been reported. Among 70 samples obtained in 2001, the predominant env subtype was CRF06-cpx, followed by CRF02-AG, subtypes A and G. Nineteen of the 70 samples from 2001 had discordant subtype or circulation recombinant form (CRF) designations between env and gag. In contrast to surrounding countries, CRF06 is predominant in Burkina Faso. This virus was probably introduced early in the HIV epidemic because of its high representation in strains tested in 1996.