For the first time, scientists have managed to map the routes by which the HIV virus spreads across the world, revealing how geopolitical factors such as migration and trade played a major role in channeling the epidemic. Among the many interesting findings to emerge from this research is that Eastern Europe remained largely shielded from the disease until the early 1990s, thanks to the so-called Iron Curtain that stifled the flow of immigration between the Communist East and the Capitalist West.
The HIV-1 subtype B virus is thought to have first made its way from Africa to Haiti in the 1970s, from where it travelled to North America. Remaining silent for around a decade, the disease managed to spread through a large proportion of the population – predominantly via same-sex sexual intercourse and the sharing of needles by intravenous drug users – so that by the time it was discovered in the 80s, it had already established a pandemic.
According to the study, which appears in the Journal of Molecular Epidemiology and Evolutionary Genetics of Infectious Diseases, the virus is one of the fastest evolving human pathogens, with a rapidly mutating genome. By trawling through the existing literature on HIV, the researchers were able to analyze the genomes of more than 9,000 strains, using this data to trace these mutations back through time and track the movement of the virus across the world.
In doing so, they found that North America has been the major exporter of HIV to Europe, with the virus having been carried across the Atlantic on a number of different occasions over the past three decades. However, while both Western and Northern Europe have received a number of HIV strains from America, the disease hardly spread into the Soviet Block during the 70s and 80s, only making its way eastwards in the early 1990s when migration restrictions were lifted.
The small number of HIV transmissions eastwards across the Iron Curtain then led to the development of highly segregated strains, which evolved in isolation from those in the west.
Image: The Iron Curtain restricted migration between the communist east and the capitalist west. Hsinghsarao via Wikimedia Commons