title: The changing molecular epidemiology of HIV type 1 among northern Thai drug users, 1999 to 2002.
abstract: CRF01_AE and subtype B have dominated the HIV-1 epidemic in Thailand since 1989. We reported a new circulating recombinant form of HIV-1, CRF15_01B, as well as other unique CRF01_AE/B recombinants among prevalent HIV infections in Thailand. We sought to study this challenging molecular picture through assessment of subtypes among recent HIV-1 seroconverters in northern Thai drug users. A total of 847 HIV-1 seronegative drug users (342 IDU and 505 non-IDU) were enrolled, from 1999 to 2002, in a prospective study; 39 HIV-1 incident cases were identified and characteristics were collected. The overall HIV-1 incidence rate was 2.54/100PY, but it was 10.0/100PY among male IDU. HIV was strongly associated with injection history; 38 of 39 seroconverters gave a history of IDU. A near full-length genome of HIV-1 was recovered by PCR amplification and sequenced from peripheral mononuclear cell extracted DNA of 38 seroconverters. Phylogenetic analysis revealed that 33 (86.8%) were CRF01_AE and 5 (13.2%) were CRF01_AE/B recombinants. These recombinants had different structure but shared some common breakpoints, indicating an ongoing recombination process. Recombinant infection increased with year of sampling (0 to 57.1%). The molecular epidemiology of HIV-1 among drug users in northern Thailand has thus entered a new era. CRF01_AE remains predominant while pure subtype B is becoming rare, and now a substantial component of the epidemic. These findings support the need for CRF01_AE and subtype B components in clade-matched vaccine strategies for Thai phase III trials. Ongoing molecular surveillance of circulating HIV-1 strains is imperative for the evaluation of HIV vaccine efficacy.
authors.affiliation: Research Institute for Health Sciences, Chiang Mai University, Chiang Mai, Thailand. stovanabutra@hivresearch.org
authors.forename: Sodsai
authors.initials: S
authors.lastname: Tovanabutra
authors.forename: Chris
authors.initials: C
authors.lastname: Beyrer
authors.forename: Supachai
authors.initials: S
authors.lastname: Sakkhachornphop
authors.forename: Myat Htoo
authors.initials: MH
authors.lastname: Razak
authors.forename: Gabriela L
authors.initials: GL
authors.lastname: Ramos
authors.forename: Tassanai
authors.initials: T
authors.lastname: Vongchak
authors.forename: Kittipong
authors.initials: K
authors.lastname: Rungruengthanakit
authors.forename: Pongpran
authors.initials: P
authors.lastname: Saokhieo
authors.forename: Kwanchanok
authors.initials: K
authors.lastname: Tejafong
authors.forename: Bohye
authors.initials: B
authors.lastname: Kim
authors.forename: Mark
authors.initials: M
authors.lastname: De Souza
authors.forename: Merlin L
authors.initials: ML
authors.lastname: Robb
authors.forename: Deborah L
authors.initials: DL
authors.lastname: Birx
authors.forename: Jaroon
authors.initials: J
authors.lastname: Jittiwutikarn
authors.forename: Vinai
authors.initials: V
authors.lastname: Suriyanon
authors.forename: David D
authors.initials: DD
authors.lastname: Celentano
authors.forename: Francine E
authors.initials: FE
authors.lastname: McCutchan
mesh_terms: D001483:Base Sequence; D017931:DNA Primers; D005260:Female; D015658:HIV Infections / Q000150:complications* / Q000453:epidemiology* / Q000821:virology; D015497:HIV-1 / Q000235:genetics*; D006801:Humans; D008297:Male; D017720:Molecular Epidemiology; D011995:Recombination, Genetic; D015819:Substance Abuse, Intravenous / Q000150:complications*; D013785:Thailand
chemical_list: D017931:DNA Primers