Scientists have found that the HIV pandemic originated in almost certainly began in Kinshasa, the capital of the Democratic Republic of the Congo.
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.
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.
One of the factors the team's analysis suggested 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.
The team's evidence suggested that, alongside transport, social changes such as the changing behaviour of sex workers, and public health initiatives against other diseases that led to the unsafe use of needles may have contributed to turning HIV into a full-blown epidemic, supporting ideas originally put forward by study co-author Jacques Pepin from the Universite de Sherbrooke, Canada.
The team said that more research was needed to understand the role different social factors may have played in the origins of the HIV pandemic; in particular research on archival specimens to study the origins and evolution of HIV, and research into the relationship between the spread of Hepatitis C and the use of unsafe needles as part of public health initiatives may give further insights into the conditions that helped HIV to spread so widely.
A report of the research is published in Science.