Deep in the forests of south-eastern Cameroon, circa the year 1900, a chimpanzee fell to the hunter's gun. It was one more hunk of African bushmeat. It was also carrying a virus that would enter the hunter's bloodstream and mutate into HIV.

Before this, such outbreaks would have remained localised, argues a provocative new book. But by then the "scramble for Africa" was under way and thousands of porters were crossing through the area. So it was, the authors claim, that colonisation by the European powers a century ago is responsible for unleashing HIV on the world.

Piecing together new and established research, Craig Timberg and Daniel Halperin, authors of Tinderbox: How the West Sparked the Aids Epidemic and How the World Can Finally Overcome It, argue that once the virus made the jump from chimp to human, a single infected person could have carried it down the Congo river into what is now Kinshasa, in the Democratic Republic of the Congo. Founded by the Belgians – a particularly brutal colonial regime – as Leopoldville in 1881, Kinshasa became the biggest city in central Africa, making it relatively easy for disease to spread through trade routes. It was "ground zero" in the explosion of HIV.

Timberg and Halperin write: "To fulfill its grim destiny, HIV needed a kind of place never before seen in central Africa but one that now was rising in the heart of the region: a big, thriving, hectic place jammed with people and energy, where old rules were cast aside amid the tumult of new commerce.

"It needed Kinshasa. It was here, hundreds of miles downriver from Cameroon, that HIV began to grow beyond a mere outbreak. It was here that Aids grew into an epidemic."

In an excerpt published in the Washington Post last week, the authors conclude: "Without 'the scramble for Africa', it's hard to see how HIV could have made it out of southeastern Cameroon to eventually kill tens of millions of people. Even a delay might have caused the killer strain of HIV to die a lonely death deep in the forest."