More than 30 years after HIV AIDS emerged as a modern day epidemic, scientists finally think they know where it originated from.
A genetic analysis of thousands of individual viruses has confirmed beyond reasonable doubt that HIV first emerged in Kinshasa, the capital of the Belgian Congo, in about 1920 from where it spread thanks to the colonial railway network to other parts of central Africa.
Scientists have nailed the origin of the Aids pandemic to a colonial-era city — then called Leopoldville which was then the biggest urban centre in Central Africa including a market in wild “bush meat” captured from the nearby forests.
A “perfect storm” of factors then led to the virus’ allowed the deadly virus to spread in the human population.
The report mentions that a roaring sex trade, rapid population growth and unsterilised needles used in health clinics probably spread the virus.
Meanwhile Belgium-backed railways had one million people flowing through the city each year, taking the virus to neighbouring regions.
Experts said it was a fascinating insight into the start of the pandemic.
HIV came to global attention in the 1980s and has infected nearly 75 million people.
The research group analysed mutations in HIV’s genetic code.
“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,” Prof Oliver Pybus from the University of Oxford told the BBC.
By reading those mutational marks, the research team rebuilt the family tree and traced its roots.
HIV is a mutated version of a chimpanzee virus, known as simian immunodeficiency virus, which probably made the species-jump through contact with infected blood while handling bush meat.
The virus made the jump on multiple occasions. One event led to HIV-1 subgroup O which affects tens of thousands in Cameroon.
Yet only one cross-species jump, HIV-1 subgroup M, went on to infect millions of people across every country in the world.
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.”