The changing molecular epidemiology of HIV type 1 among northern Thai drug users, 1999 to 2002.
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.
Tovanabutra
Sodsai
S
Research Institute for Health Sciences, Chiang Mai University, Chiang Mai, Thailand. stovanabutra@hivresearch.org
Beyrer
Chris
C
Sakkhachornphop
Supachai
S
Razak
Myat Htoo
MH
Ramos
Gabriela L
GL
Vongchak
Tassanai
T
Rungruengthanakit
Kittipong
K
Saokhieo
Pongpran
P
Tejafong
Kwanchanok
K
Kim
Bohye
B
De Souza
Mark
M
Robb
Merlin L
ML
Birx
Deborah L
DL
Jittiwutikarn
Jaroon
J
Suriyanon
Vinai
V
Celentano
David D
DD
McCutchan
Francine E
FE
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
D017931:DNA Primers