title: Molecular epidemiology of HIV type 1 subtypes in Taiwan: outbreak of HIV type 1 CRF07_BC infection in intravenous drug users.
abstract: In Taiwan, sexual transmission is responsible for most HIV-1 infections with two dominant subtypes, subtype B and CRF01_AE, distributing among homosexual and heterosexual groups, respectively. Recently, intravenous drug use has become an emerging route of HIV-1 transmission and contributed to a significant increase of HIV-1 infection. To characterize the HIV isolates responsible for the outbreak among intravenous drug users (IDUs), phylogenetic analysis was performed to analyze the protease/RT sequences amplified from HIV-1-infected IDUs at National Taiwan University Hospital and Taipei City STD Control Center. CRF07_BC, which is circulating in northern China, was demonstrated to account for the majority of HIV-1 infection in IDUs in the past 2 years. Although these Taiwanese CRF07_BC sequences shared the same breakpoint positions as those described in the CRF07_BC reference sequences, they formed a unique cluster in the phylogenetic tree, suggesting they originated from a founder virus. This finding was further supported by the relative low genetic diversity and unique sequence features. Our results demonstrated the emergence of CRF07_BC and its association with the HIV-1 outbreak among IDUs between 2004 and 2005 in Taiwan. This finding not only helps us to have a better understanding of the HIV evolution in Asia, but also has important implications for vaccine design in the future.
authors.affiliation: Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Sui-Yuan
authors.initials: SY
authors.lastname: Chang
authors.forename: Wang-Huei
authors.initials: WH
authors.lastname: Sheng
authors.forename: Chun-Nan
authors.initials: CN
authors.lastname: Lee
authors.forename: Hsin-Yun
authors.initials: HY
authors.lastname: Sun
authors.forename: Chuan-Liang
authors.initials: CL
authors.lastname: Kao
authors.forename: Shu-Fang
authors.initials: SF
authors.lastname: Chang
authors.forename: Wen-Chun
authors.initials: WC
authors.lastname: Liu
authors.forename: Jr-Yuan
authors.initials: JY
authors.lastname: Yang
authors.forename: Wing-Wai
authors.initials: WW
authors.lastname: Wong
authors.forename: Chien-Ching
authors.initials: CC
authors.lastname: Hung
authors.forename: Shan-Chwen
authors.initials: SC
authors.lastname: Chang
mesh_terms: D004196:Disease Outbreaks; D015658:HIV Infections / Q000453:epidemiology* / Q000821:virology*; D015497:HIV-1 / Q000235:genetics*; D006801:Humans; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D010802:Phylogeny; D015819:Substance Abuse, Intravenous / Q000150:complications*; D013624:Taiwan / Q000453:epidemiology; D013997:Time Factors