Chapter 5 sets the stage for the rest of the story. While several infectious agents were exported from Africa to the Americas and the Caribbean during the slave trade, this was not the case with HIV, which indirectly confirms its relatively recent emergence in central African populations. This chapter briefly tells the story of the European colonisation of central Africa by France and Belgium. It explains how the Franco-Belgian incursion in south-east Cameroon during World War I (1914–16) created much greater intermingling of populations and may have provided a route for HIV to reach the Stanley Pool.

Chapter 14 assembles the pieces of the puzzle described in the preceding twelve chapters into a coherent narrative of HIV’s journey, from when the first patient was infected somewhere in south-east Cameroon at the turn of the twentieth century until this ‘new’ disease was recognised in the USA in June 1981. The virus first travelled from its Cameroonian crucible to Léopoldville (Kinshasa), where it arrived around 1920, brought either by the crew of the steamships that transported various commodities for export or by troops from the two Congos that had been dispatched to invade south-east Cameroon during the Great War. Léopoldville was the turning point in HIV’s fateful journey, the place where it slowly progressed over some thirty years before expanding more rapidly in the 1950s.

Chapter 7 reviews the development of different types of prostitution driven by the gender imbalance in the nascent cities of central Africa, especially Léopoldville and Brazzaville. It describes how this core group played a key role in the dynamics of all sexually transmitted pathogens, including HIV. Initially, ‘soft’ prostitution, where ‘free women’ had three or four regular clients who visited them on a weekly basis, had low potential for amplifying HIV. After the turmoil of the Belgian Congo’s independence in 1960, however, a new type of prostitution emerged, where sex workers had intercourse with three or four different men every day, or more than 1,000 per year, which enabled the sexual amplification of HIV. The life and work of Suzanne Comhaire-Sylvain provide an early example of the links between Haiti and the Congo. She was a Haitian anthropologist who studied prostitution in Léopoldville and described the profound changes in the sex trade in the early 1960s.

Chapter 6 explains how the process of colonisation profoundly altered the ways of life of peoples in the Belgian Congo, Moyen-Congo and Cameroon, through accelerated urbanisation and the pronounced gender imbalance in the cities that resulted from colonial policies. It focuses on Léopoldville, which for a few decades was essentially a labour camp. The chapter ends with a review of how the Stanley Pool, where Léopoldville and Brazzaville were located, has always been the natural terminus for all traffic in the huge River Congo basin, and thus a melting pot of dozens of ethnic groups.