The global spread of HIV-1 subtype B epidemic

77 Human immunodeficiency virus type 1 (HIV-1) was discovered in the early 1980’s when the 78 virus had already established a pandemic. For at least three decades the epidemic in the 79 Western World has been dominated by subtype B infections, as part of a sub-epidemic that 80 traveled from Africa through Haiti to United States. However, the pattern of the subsequent 81 spread still remains poorly understood. Here we analyze a large dataset of globally 82 representative HIV-1 subtype B strains to map their spread around the world over the last 50 83 years and describe significant spread patterns. We show that subtype B travelled from North 84 America to Western Europe in different occasions, while Central/Eastern Europe remained 85 isolated for the most part of the early epidemic. Looking with more detail in European 86 countries we see that the United Kingdom, France and Switzerland exchanged viral isolates 87 with non-European countries than with European ones. The observed pattern is likely to 88 mirror geopolitical landmarks in the post-World War II era, namely the rise and the fall of the 89 Iron Curtain and the European colonialism. In conclusion, HIV-1 spread through specific 90 migration routes which are consistent with geopolitical factors that affected human activities 91 during the last 50 years, such as migration, tourism and trade. Our findings support the 92 argument that epidemic control policies should be global and incorporate political and 93 socioeconomic factors .