Leelawiwat W, Rutvisuttinunt W, Arroyo M, Mueanpai F, Kongpechsatit O, Chonwattana W, Chaikummao S, de Souza M, vanGriensven DF, McNicholl JM, Curlin M.
Original Article: 1.usa.gov/10WIlhV
Background: In Thailand, new HIV-1 infections are largely concentrated in certain risk groups such as men who have sex with men (MSM), where annual incidence may be as high as 12% per year. The paucity of information on the molecular epidemiology of HIV-1 in Thai MSM limits progress in understanding the epidemic and developing new prevention methods. We evaluated HIV-1 subtypes in seroincident and seroprevalent HIV-1 infected men enrolled in the Bangkok MSM Cohort Study (BMCS) between 2006 and 2011. Methods: We characterized HIV-1 subtype in 231 seroprevalent and 194 seroincident subjects using the multihybridization assay (MHA). Apparent dual infections, recombinant strains, and isolates found to be non-typeable by MHA were further characterized by targeted genomic sequencing. Results: Most subjects were infected with HIV-1 CRF01_AE (82%), followed by infections with recombinants (11%, primarily CRF01_AE/B recombinants), subtype B (5%), and dual infections (2%). More than 11 distinct chimeric patterns were observed among CRF01B_AE/B recombinants, most involving recombination within integrase. A significant increase in the proportion of non-typeable strains was observed among seroincident MSM between 2006 and 2011. Conclusion: CRF01_AE and subtype B were the most and least common infecting strains, respectively. The predominance of CRF01_AE among HIV-1 infections in Thai MSM participating in the BMCS parallels trends observed in Thai heterosexuals and injecting drug users. The presence of complex recombinants, and a significant rise in non-typeable strains suggest ongoing changes in the genetic makeup of the HIV-1 epidemic in Thailand, which may pose challenges for HIV-1 prevention efforts and vaccine development.
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