1920s Kinshasa was ground zero for HIV, gene sequencing shows
Growth spurt in Congolese city created 'perfect storm' for deadly virus to begin multiplying, gene sequencing and historical records show
A "perfect storm" of urban change that began in the 1920s in Kinshasa led to the catastrophic spread of HIV across Africa and the world, according to scientists who used genetic sequencing and historical records to trace the origins of the pandemic.
Though the virus probably crossed from chimpanzees to humans in southern Cameroon years earlier, HIV remained a regional infection until it entered the capital of what is now the Democratic Republic of the Congo, according to research published on Thursday in the magazine Science.
An international team led by the universities of Oxford in Britain and Leuven in Belgium reconstructed the history of the HIV pandemic using historical records and DNA samples of the virus dating back to the late 1950s.
The DNA allowed them to draw up a family tree of the virus that traced its ancestry. Using statistical models they could push farther back than the 1950s and locate its origin to Kinshasa.
When the virus arrived, booming Kinshasa was the largest and fastest growing city in the region with transport links across the country.
Records show that by the 1940s, more than a million people a year passed through Kinshasa on the railways alone. By 1960, the rate of new pandemic HIV infections outpaced the growth of the regional population, according to Science.
People with HIV in central Africa at the time of its origin in the 1920s did not have specific symptoms that would have been put on their medical records. The virus causes the immune system to collapse, leaving allowing for all manner of infections.