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Cross-Border Spread of Closely Related HIV-1 Subtype E Variant among Injecting Drug Users (IDUs) in Chino-Vietnam Boundary Y. TAKEBW*1, K. KATO1, S. KUSAGAWA1, K. MOTOMURA1, K. NOHTOMI1, T. SHIINO1, H. SATO1, N. T. HIEN2, H. T. LONG2, S. YAMAZAKI1, and Y. NAGAI1. 1AIDS Res. Ctr., Natl. Inst. of Infectious Diseases, Tokyo, Japan; and 2Natl. Inst. of Hygiene and Epidemology, Hanoi, Vietnam To investigate the nature of recent HIV outbreaks among IDUs in northern Vietnam, we genetically analyzed 24 HIV(+) blood specimens from two provinces [Lang Son (LS) and Quang Ninh (QN)] adjacent to the China border, where the first HIV outbreaks were detected among IDUs in northern Vietnam in late 1996. Genetic subtyping based on gag p17 and env C2/V3 sequences revealed that HIV-1 subtype A/E recombinant predominates in all risk populations throughout Vietnam. Notably, HIV-1 subtype E identified in QN (13/14) and LS (6/10) were closely related phylogenetically to those found in nearby Guangxi province (GX) of China. They shared the unique valine substitution at 12 amino acids downstream of the V3 loop. This particular subtype E variant uniquely found among IDUs at the Chino-Vietnam boundary was designated as "Ev". The interperson nucleotide diversity among IDUs in QN was markedly low (1.5 ±0.6%), whereas that in LS (3.7± 1.8%) was rather higher than in other northern provinces near Hanoi (2.7 ± 1.3%), suggesting that the epidemic in LS appears to have started earlier than those in other regions in northern Vietnam. Taken together, the data indicated that the HIV outbreak among IDUs in northern Vietnam was caused by a recent introduction of a highly homogeneous subtype E variant (Ev) of similar origin to the virus prevailing in nearby GX of southern China. Key Words: IDUs, MOLECULAR EPIDEMOLOGY, NORTHERN VIETNAM |
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© 7th
Conference on Retroviruses and Opportunistic Infections, |