AEGiS-15IAC: Geographical hotspots of extensive intersubtype recombination in Asia: "Melting pot" that generates diverse forms of HIV-1 unique recombinant forms.

15th International AIDS Conference

Bangkok, Thailand - July 11-16, 2004

Geographical hotspots of extensive intersubtype recombination in Asia: "Melting pot" that generates diverse forms of HIV-1 unique recombinant forms.

Int Conf AIDS 2004 Jul 11-16; 15:(abstract no. ThOrA1364)

Takebe Y, Ma Y, Yang C, Yokota Y, Kusagawa S, Yang R, Xia X, Ben K, Thwe M, Aung T, Oo KY, Lwin HH
National Institute of Infectious Diseases, Tokyo, Japan

BACKGROUND: We investigate the molecular epidemiology of HIV in Myanmar and Yunnan Province of China to study the genesis and the interrelationship of the epidemic in these two regions.

METHODS: Study was conducted among injecting drug users (IDUs) in two cities (Yangon and Mandalay) in Myanmar and three study sites [Wenshan and Honghe (east) and Dehong (west)] in Yunnan. The nucleotide sequences of 2.6-kb gag-RT region or near full-length genome were determined. The subtype structure was examined by bootscanning, informative site and subregion tree analyses. The precise locations of recombination breakpoints were compared.

RESULTS: We found that 10-30% of HIV-1 strains in Central Myanmar were unique recombinant forms (URFs) comprised of subtypes B' and C and CRF01_AE. In contrast, subtype B' predominated in Yangon. We found the unique disparity of subtype distribution in Yunnan. CRF08_BC predominated throughout Yunnan. However, 2/3 were URFs comprised of subtypes B' and C, and 1/3 was subtype B' in western Yunnan. In addition, a new class of HIV-1 recombinants (inter-CRF recombinants) between CRF07_BC and CRF08_BC were detected in Honghe. Fine mapping of recombination breakpoints revealed that some Mandalay URFs shared the precise breakpoints with CRF07_BC and CRF08_BC, suggesting that they may have been evolved from common ancestors.

CONCLUSIONS: We identified unique geographical hotspots of extensive recombination in Central Myanmar and western Yunnan, where diverse forms of recombinant strains appear to be arising continually. This may reflect the presence of the highly exposed individuals and social networks in these regions. Our study also represents the first evidence that may suggest the linkage of the epidemic between these two regions. The rapid emergence and evolution of diverse forms of recombinants could further complicate the development of efficacious vaccines to limit HIV-1 spread in these particular areas in Asia.

Keywords: AEGIS, HIV-1, Recombination, Genetic, Acquired Immunodeficiency Syndrome, China, Epidemiology, Molecular, Base Sequence, Disease Outbreaks, Genes, gag, Asia, Myanmar, genetics

040711
ThOrA1364