The spread of minority HIV-1 strains in Hong Kong

Abstract

In the last decade, various molecular assays and sequencing techniques have vulgarized the HIV-1 epidemiological and phylogenetic study across the major continents. HIV-1 group M is divided into many subtypes, and dominates in different parts of the world. Being one of the busiest harbor ports, Hong Kong has a mosaic genetic diversity. During the period of 2000 – 2012, both subtypes B and CRF01_AE had accounted for about 80% of HIV-1 infection in Hong Kong. This study aimed to investigate the remaining 20% of the minority HIV-1 strains in our region. A total of 1995 HIV-1 infected patients, who sought medical consultation at the Government Integrated Treatment Centre during 2000 – 2012, were included in this study. HIV-1 pol genes were sequenced by our in-house genotyping assay and preliminary subtyped by REGA. The minority strains included 4.4% subtype C, 3.2% CRF07_BC, 1.1% CRF02_AG, 0.9% subtype A1, 0.7% CRF08_BC, and <1% subtype G, D, CRF06_cpx and CRF12_BF. Phylogenetic analysis revealed 4 different groups in subtype C, that were transmitted through heterosexual African, heterosexual non-Chinese Asian, heterosexual Chinese and needle-sharing non-Chinese Asian. Two major clusters from homosexual Chinese and needle-sharing Chinese were also observed in CRF07_BC. The number of cases was limited in other minor subtypes and no clusters were observed. Due to huge volume of tourism from China, subtype C and CRF07_BC were suspected to have been imported through the borders. Closer monitoring is required on these minorities to prevent establishment and larger spread in the future.