The origins of the AIDS pandemic have been traced back to 1920s Kinshasa in what is now the Democratic Republic of the Congo, 60 years before the disease first came to international attention. It has now infected nearly 75 million people.
Researchers from Oxford and Leuven used mutations in the virus’s genetic code to discover its roots. It is thought to have originated in chimpanzees before making the jump to humans.
When it arrived in Kinshasa, the city was growing rapidly. Thousands of male labourers had poured in, so that they outnumbered women by two to one. A thriving sex industry developed and medical records show that sexually transmitted disease was widespread.
It seems the virus then travelled via the railway network, and through vaccination campaigns where unsterilised needles were used. The researchers describe the conditions prevailing in 1920’s Kinshasa as a ‘perfect storm’.