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A team of scientists from Oxford and Belgium have traced the AIDS pandemic all the way back to 1920’s Kinshasa – in what is now the Democratic Republic of Congo. 

The team composed of scientists from Oxford University and Leuven, in Belgium, used archive samples of the HIV genetic, along with viral and social archaeology to trace the origins of the AIDS pandemic back to Kinshasa in the 1920s the team have reported in the journal Science.

The combination of a prosperous sex trade, unsterilised needles used in health clinics, and a population boom would have helped spread the virus. At the same time new railway lines, backed by the Belgians, enabled one million people to pass through Kinshasha every year – and on to other regions.

Although HIV/AIDS has a much longer history in Africa, finding the source of the modern pandemic has been a subject of great curiosity for scientists studying the virus.

The team set about recreating the “HIV Family Tree” using archived samples and recording mutations in HIV’s genetic code.

Prof Oliver Pybus from the University of Oxford said “You can see the footprints of history in today’s genomes, it has left a record, a mutation mark in the HIV genome that can’t be eradicated.”

HIV is a mutated version of the simian immunodeficiency virus (SIV), which is thought to have made the jump from primates to humans through contact with infected blood while handling bush meat.

The virus has made the species-jump on numerous occasions. One jump bore HIV-1 subgroup O which now affects large numbers of people across Cameroon. But only one species-jump, the one which created HIV-1 subgroup M, ended up traversing the planet and infecting people everywhere.

Back in 1920’s Kinshasha the gender balance reached one woman to every two men which fueled a booming sex industry. Programmes to treat sexually transmitted infections may have actually further compounded the issue through use of shared and unsterilised needles. This combined with the busy railway lines in the area lead to a “perfect storm” effect.

Dr Andrew Freedman, a reader in infectious diseases at Cardiff University, said: “It does seem an interesting study demonstrating very elegantly how HIV spread in the Congo region long before the Aids epidemic was recognised in the early 80s.

“It was already known that HIV in humans arose by cross species transmission from chimpanzees in that region of Africa, but this study maps in great detail the spread of the virus from Kinshasa, it was fascinating to read.”

Prof Jonathan Ball, from the University of Nottingham, said: “It’s a fascinating insight into the early phases of the HIV-1 pandemic. 

“It’s the usual suspects that are most likely to have helped the virus get a foothold in humans – travel, population increases and human practices such as unsafe healthcare interventions and prostitution.

“Perhaps the most contentious suggestion is that the spread of the M-group viruses had more to do with the conditions being right than it had to do with these viruses being better adapted for transmission and growth in humans. I’m sure this suggestion will prompt interesting and lively debate within the field.”

Source: Science Journal. Paid subscription. http://www.sciencemag.org/content/346/6205/56.abstract

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