From News.com

A new genetic history of HIV shows how the pandemic almost certainly took root in the 1920s in Kinshasa in the Democratic Republic of Congo, researchers said.

Assisted by train transport and the sex trade, the virus that causes AIDS then spread across the continent and eventually the world, infecting some 75 million people and killing 36 million of them.

An international team of researchers reconstructed the genetic history of the HIV-1 group M pandemic, and found that the common ancestor of group M is “highly likely” to have emerged in Kinshasa around 1920.

While various strains of human immunodeficiency virus (HIV) have jumped from primates and apes to humans at least 13 times, only one such transmission event has led to a human pandemic.

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