Transmission dynamics of HIV-1 subtype B strains in Indonesia.

Human immunodeficiency virus type 1 (HIV-1) and acquired immunodeficiency syndrome (AIDS) represent a major public health concern in Indonesia. Although circulating recombinant form (CRF) 01_AE is a predominant subtype in Indonesia, HIV-1 subtype B (HIV-1B) is also widely prevalent. However, the viral genetic evolution, spatial origins, and patterns of transmission of HIV-1B in Indonesia remain unclear. In the present study, we described the evolutionary characteristics and spatial-temporal transmission networks of HIV-1B in Indonesia. To elucidate the epidemiological link between HIV-1B epidemics in Indonesia and those in the remainder of the world, we conducted phylogenetic analyses of HIV-1B strains in Indonesia. Based on the results obtained, at least three epidemic clades [the Indonesia, United States (US), and China clades] of HIV-1B were found to be prevalent in Indonesia. In order to identify the potential source and transmission route of Indonesian HIV-1B strains, we performed Bayesian analyses and constructed Maximum clade credibility trees of each clade. Although some HIV-1B strains in Indonesia were introduced from Thailand, the prevalent HIV-1B strains appeared to have been directly introduced from Europe or America. Indonesian HIV-1B may have spread via the main dispersal of pandemic HIV-1B strains via the US from the Caribbean region rather than being directly introduced from Africa.