title: Phylodynamics of HIV-1 subtype B among the men-having-sex-with-men (MSM) population in Hong Kong.
abstract: The men-having-sex-with-men (MSM) population has become one of the major risk groups for HIV-1 infection in the Asia Pacific countries. Hong Kong is located in the centre of Asia and the transmission history of HIV-1 subtype B transmission among MSM remained unclear. The aim of this study was to investigate the transmission dynamics of HIV-1 subtype B virus in the Hong Kong MSM population. Samples of 125 HIV-1 subtype B infected MSM patients were recruited in this study. Through this study, the subtype B epidemic in the Hong Kong MSM population was identified spreading mainly among local Chinese who caught infection locally. On the other hand, HIV-1 subtype B infected Caucasian MSM caught infection mainly outside Hong Kong. The Bayesian phylogenetic analysis also indicated that 3 separate subtype B epidemics with divergence dates in the 1990s had occurred. The first and latest epidemics were comparatively small-scaled; spreading among the local Chinese MSM while sauna-visiting was found to be the major sex partner sourcing reservoir for the first subtype B epidemic. However, the second epidemic was spread in a large-scale among local Chinese MSM with a number of them having sourced their sex partners through the internet. The epidemic virus was estimated to have a divergence date in 1987 and the infected population in Hong Kong had a logistic growth throughout the past 20 years. Our study elucidated the evolutionary and demographic history of HIV-1 subtype B virus in Hong Kong MSM population. The understanding of transmission and growth model of the subtype B epidemic provides more information on the HIV-1 transmission among MSM population in other Asia Pacific high-income countries.
authors.affiliation: Department of Microbiology, Queen Mary Hospital, the University of Hong Kong, Hong Kong Special Administrative Region, China.
authors.forename: Jonathan Hon-Kwan
authors.initials: JH
authors.lastname: Chen
authors.forename: Ka-Hing
authors.initials: KH
authors.lastname: Wong
authors.forename: Kenny Chi-Wai
authors.initials: KC
authors.lastname: Chan
authors.forename: Sabrina Wai-Chi
authors.initials: SW
authors.lastname: To
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Chen
authors.forename: Wing-Cheong
authors.initials: WC
authors.lastname: Yam
mesh_terms: D000328:Adult; D015658:HIV Infections / Q000453:epidemiology* / Q000635:transmission / Q000821:virology*; D015497:HIV-1 / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity; D018451:Homosexuality, Male; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D008297:Male; D010802:Phylogeny