14th International AIDS Conference Barcelona, Spain - July 7-12, 2002

Int Conf AIDS 2002 Jul 7-12; 14:(abstract no. TuOrC1195)

Vergne L, Bourgeois A, Mpoudi-Ngole E, Mougnoutou R, Muagbaw J, Zekeng L, Liegeois F, Butel C, Peeters M, Delaporte E
IRD, Montpellier, France

BACKGROUND: The HIV-1 epidemic in Cameroon is characterized by an extensive genetic variability, where all groups (M, N and O) and subtypes cocirculate, and by a high variety of intersubtype and intergroup recombinants. In this study, we examined whether the subtype distribution changed over time.

METHODS: Since 1996, 1021 HIV-1 samples from patients attending the military hospital in Yaounde were tested with a V3-loop peptide ELISA to discriminate between HIV-1 group M, N and O. 286 group M samples were genetically characterized in the env V3-V5 region, and a subset of these samples (n=111) were also subtyped in gag (p24) to identify eventual recombinants. Genotyping is performed by sequencing and phylogenetic analyses. The samples reacting simultaneously with O and M peptides were tested by PCR using O and M specific primers in env (C2V3 and gp41) to examine the presence of dual infection.

RESULTS: Among the 1021 HIV-1 samples, 85.2% were identified as M, 1.2% O, 0.1% N and 4.3% were reactive with O and M peptides. Among 286 M samples, the phylogenetic analyses of env showed that CRF02_AG predominates (64.4%), this prevalence decreased slightly between 1997 to 1999 (68.6% to 55.4%) but not significantly (P=0.089). Many other subtypes and CRFs cocirculate: A(13.4%), CRF11(5%), F2(4.5%), D(4.2%), G(3.2%), H(2.1%), CRF06(1.7%), B(0.3%), C(0.3%), F1(0.3%), K(0.3%) and CRF01(0.3%). 12% of the samples had discordant subtype or CRF designations between env and gag and, in 61% of these samples, CRFs were involved in recombination. At least, 7 dual group O and M infections and 1 intergroup recombinant were observed.

CONCLUSIONS: These data showed that the subtype A and CRFs subclustering with subtype A in env and gag (CRF02, CRF11) are largely predominant in Cameroon, but all groups and subtypes are represented. No significant changes were seen over time. The presence of inter-subtype and -group viruses proved a high level of past and present coinfections.

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TuOrC1195

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