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13th International AIDS ConferenceDurban, South Africa - July 9-July 14, 2000 |
Int Conf AIDS 2000 Jul 9-14; 13:(abstract no. TuOrA411)
Peeters M, Mboup S, Ndoyi-Mbiguino A, Koyalta D, Mulanga-Kabeya C, Mpoudi-Ngole E
M. Peeters, IRD Laboratoire retrovirus, 911 Avenue Agropolis, BP 5045, 34032 Montpellier Cedex 1, France, Tel.: +33-4 67 41 62 97, Fax: +33-4 67 61 94 50, E-mail: martine.peeters@mpl.ird.fr
BACKGROUND:To identify and characterize HIV-1 viruses that circulate in west and west central africa, and to determine their relative prevalence.
METHODS: More than 1500 HIV-1 postive samples were characterized in the V3-V5 region of the envelope, by HMA(heteroduplex mobility assay) and/or sequencing.The samples were collected between 1997 and 1999, in 8 different countries (Senegal,Mali,Niger,Nigeria,Chad,Cameroon,Gabon and DRC (ex-Zaire)).For more than a quarter of these samples,the genetic subtype was also identified in the gag region.
RESULTS: By HMA,the predominant env subtype is A ,however decreasing from west to west central Africa (85% to less than 50%). Subtype G was seen in all the countries,and represents >25% of the viruses in Nigeria. Subtypes E,F1,F2,H,J and K were more prevalent in west central Africa. The frequency of discordant subtypes between gag and env ranges from 10% (in Senegal,Cameroon,Gabon) to up to 30% in Nigeria and DRC. Many samples (60 to 80%), identified as subtype A in env and/or gag form a separate cluster with the AG-IBNG virus. Full-length genome sequencing confirmed that they had a similar complex mosaic AG structure as AG-IBNG, suggesting that AG-IBNG viruses are predominant in west Africa and to a lesser extend in central Africa. Many other complex recombinant viruses circulating in different countries were documented AGJ?-BFP90 like viruses, a complex AJ? virus and a reombinant intergroup O/M virus in Cameroon.
CONCLUSION: In each country,the majority of the known HIV-1 subtypes and CRF (circulating recombinant forms) cocirculate,but their prevalences vary. Also within a country,geographical differences in subtype distribution are seen. Higher intrasubtype distances are seen in Central Africa,especially DRC. The prevalence of recombinant viruses is relative high,and recombinant viruses continue to recombine (AG-IBNG viruses recombined with F, D, O, ...). Genetic subtype distribution is a dynamic and unpredictable process.
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