Free The Chimp and the River: How AIDS Emerged from an African Forest by David Quammen Page A

boondocks, but not yet so unlike as they would become. The arithmetic of the outbreak was still modest, with scarcely more than a single transmission onward per infected person. In the language of disease ecologists: the basic reproduction rate (the average number of secondary infections from each primary infection at the beginning) barely exceeded 1.0, the minimal level required for the outbreak to continue indefinitely. Then, as time passed, more people drifted into the towns, drawn by the prospect of working for wages or selling their goods. Habits and opportunities changed. Women came as well as men, though not so many of them, and among those who did, more than a few entered the sex trade.
    By 1914, Brazzaville contained about six thousand people and was “a hard mission field,” according to one Swedish missionary, where “hundreds of women from upper Congo are professional prostitutes.” It was the capital of the colony then known as French Equatorial Africa. The male population included French civil servants within the colonial administration, soldiers, traders, and laborers, and they probably outnumbered females by a sizable margin, due to colonial policies that discouraged married men, coming there to work, from bringing their families. That gender imbalance heightened the demand for commercial sex. But the format for bought favors, in those early years, was generally different from what the word “prostitute” might suggest—grindinglyefficient, wham-bam encounters with a long succession of strangers. Instead there were single women, known as ndumbas in Lingala and femmes libres in French, “free women” as distinct from wives or daughters, who would provide their clients with a suite of services, ranging from conversation to sex to washing clothes and cooking. One such ndumba might have just two or three male friends who returned on a regular basis and kept her solvent. Another variant was the ménagère , a “housekeeper” who lived with a white colonial official and did more than keep house. Commercial arrangements, yes, but these didn’t represent the sort of prodigiously interconnected promiscuity that could cause a sexually transmitted virus to spread widely.
    Across the pool in Léopoldville, meanwhile, the disparity of genders was even worse. This town was essentially a labor camp, controlled by its Belgian administrators, inhospitable to families, where the male-female ratio in 1910 was ten to one. Travel through the countryside and entry into Léopoldville were restricted, especially for adult females, though some women managed to get false documents or evade the police. If you were a restless, imaginative girl in one of the villages, poorly fed and poorly treated, to be a ndumba in Léopoldville could well have seemed enticing. Here too, though, even with ten horny men for each woman, commercial sex didn’t happen in brothels or by streetwalking. Free women had their special friends, their clients, maybe several contemporaneously, but there was no dizzying permutation of multiple sexual contacts, not yet. One expert has called this “a low-risk type of prostitution,” with regard to the prospects of HIV transmission.
    Léopoldville also supported a lively market in smoked fish. Ivory, rubber, and slaves were traded there, for export, with profits going mainly to white concessionaires, well into the colonial era.Although a deep canyon and a set of forbidding cataracts stood between the Stanley Pool and the river’s mouth, isolating both cities from the Atlantic Ocean, a portage railway built in 1898 had breached that isolation, bringing more goods and commerce, which brought more people, and in 1920 Léopoldville replaced a downriver town as capital of the Belgian Congo. By 1940, its population had edged up to forty-nine thousand. Then the demographic curve steepened. Between 1940 and independence, which came in 1960, the city grew by almost an order of magnitude, to about four hundred