The HIV pandemic that has affected many people across the globe is almost certain to have begun its global spread from Kinshasa, the capital of the Democratic Republic of the Congo (DRC), according to a new study.
An international team, led by Oxford University and University of Leuven scientists, has reconstructed the genetic history of the HIV-1 group M pandemic, the event that saw HIV spread across the African continent and around the world, and concluded that it originated in Kinshasa.
The team’s analysis suggests that the common ancestor of group M is highly likely to have emerged in Kinshasa around 1920 (with 95% of estimated dates between 1909 and 1930), a release from the University of Oxford said.
HIV is known to have been transmitted from primates and apes to humans at least 13 times but only one of these transmission events has led to a human pandemic. It was only with the event that led to HIV-1 group M that a pandemic occurred, resulting in almost 75 million infections to date.
The team’s analysis suggests that, between the 1920s and 1950s, a ‘perfect storm’ of factors, including urban growth, strong railway links during Belgian colonial rule, and changes to the sex trade, combined to see HIV emerge from Kinshasa and spread across the globe.
A report of the research is published in this week’s Science.
“Until now most studies have taken a piecemeal approach to HIV’s genetic history, looking at particular HIV genomes in particular locations,” said Oliver Pybus of Oxford University’s Department of Zoology.
He added: “For the first time we have analysed all the available evidence using the latest phylogeographic techniques, which enable us to statistically estimate where a virus comes from. This means we can say with a high degree of certainty where and when the HIV pandemic originated. It seems a combination of factors in Kinshasa in the early 20th Century created a ‘perfect storm’ for the emergence of HIV, leading to a generalised epidemic with unstoppable momentum that unrolled across sub-Saharan Africa.”
One of the factors the team’s analysis suggests was key to the HIV pandemic’s origins was the DRC’s transport links, in particular its railways, that made Kinshasa one of the best connected of all central African cities.
“Data from colonial archives tells us that by the end of 1940s over one million people were travelling through Kinshasa on the railways each year,’ said Nuno Faria of Oxford University’s Department of Zoology.
“Our genetic data tells us that HIV very quickly spread across the Democratic Republic of the Congo (a country the size of Western Europe), travelling with people along railways and waterways to reach Mbuji-Mayi and Lubumbashi in the extreme South and Kisangani in the far North by the end of the 1930s and early 1950s”, Faria said.