While the link from the west lake epidemic to Dar es Salaam was strong, that to Nairobi and the Kenyan epidemic is no more than probable. Kenya’s first Aids cases were concentrated in three locations: Mombasa on the coast, Nairobi in the centre, and the Nyanza province on the eastern shore of Lake Victoria. Any of these may have infected the others, or each may have been infected separately. If HIV reached the two cities directly from west of the lake, the main link, as in Dar es Salaam, was probably women from Kagera prominent in low-status sex work in Kenya since the interwar period. Of 418 women of this kind studied in Nairobi in 1985, 358 were Tanzanians and 37 Ugandans.44 Blood specimens tested retrospectively showed that even in 1981 some 4 per cent of the city’s sex workers were infected, a proportion that grew exponentially to more than 85 per cent in 1986. Of men with genital ulcer disease attending a Nairobi clinic, 3 per cent had HIV in 1981 and 15 per cent in 1985, leaving doubt whether women or men were first infected. In 1985, 2 per cent of women at antenatal clinics also tested positive, showing that infection was spreading to the general population.45 That was the year when the Kenyan authorities belatedly admitted that the disease was present.
For epidemiologists, HIV in Nairobi was a classic example of an epidemic rapidly transmitted within a core group and then passed on by a bridging group – the sex workers’ clients – to the general population. This happened in Nairobi, as not in Kampala, partly because the Ugandan epidemic began in the countryside and partly because of differences between the cities. In 1979 Nairobi’s 827,775 people included 138 males for every 100 females, with an even larger imbalance among adults. At least half its employed men had no wife in the city.46 Wealth and poverty were sharply juxtaposed and women with little education seldom found formal jobs. The result was an exceptionally overt, mercenary style of commercial sex, especially in the Pumwani red-light district, where a community of over a thousand sex workers, many from Kagera, sat outside their rooms waiting for brief encounters with working men at a price of 30–50 US cents. Each averaged nearly a thousand partners a year, working only by day because the night was too dangerous. Some 42 per cent had genital ulcer disease.47 Study of their clients in 1986–7, when the epidemic peaked, found that 8 per cent contracted HIV from them and that 96 per cent of infected clients were either uncircumcised or had genital ulcer disease or both. Five years later, 76 per cent of women in Nairobi seeking treatment for a sexually transmitted disease reported only one partner during the previous three months and had presumably been infected by him, indicating the potential for transmission to the general population. HIV prevalence at Nairobi’s antenatal clinics may have peaked in 1994 at about 17 per cent. Four years later over 40 per cent of Kenya’s new HIV infections were thought to come through commercial sex.48
The sex workers themselves suffered terribly. Nearly half of those hitherto uninfected contracted HIV each year. They then generally developed Aids within about half the normal time, perhaps owing to multiple infection or other sexually transmitted diseases.49 Their danger was discovered almost accidentally in 1985 during a preliminary survey of sexually transmitted diseases. When astonished researchers told sex workers that two-thirds of the 60 tested had HIV, they met ‘stunned silence’. Only five wanted to know their personal status, although most quickly adopted the free condoms pressed upon them. ‘When one gets beyond the initial prejudices and stereotypes,’ the organisers wrote, ‘one finds the prostitute knowingly risking AIDS, sacrificing her own hopes for the sake of her children or brothers and sisters.’50
The explosive epidemic in Nairobi almost monopolised attention in Kenya, so that little is known of HIV elsewhere during its first decade. Perhaps misleadingly, the coast region reported three times as many Aids cases as Nairobi in 1991, the great majority no doubt in Mombasa, where 54 per cent of 3,628 sex workers tested positive between 1993 and 1997 and adult prevalence in 2000 was 10.8 per cent.51 Elsewhere prevalence during the early 1990s was relatively low, except in towns along the trans-African highway between Nairobi and the Ugandan border. In 1993 both Nakuru and Busia reported higher antenatal prevalence than either Nairobi or Mombasa. From the mid 1990s there was also rapid growth in the Central and Eastern provinces around Nairobi. Kenya’s adult infection rate probably peaked around 1998, officially at 13.9 per cent although the true mark may have been substantially lower.52
Kenya’s anomaly was the Nyanza province bordering Lake Victoria, which experienced an explosive epidemic that is perhaps the least understood in Africa. The earliest infections may have come across the lake soon after the epidemic began on its western shore, for between 1986 and 1993 Nyanza reported 15,605 Aids cases – 31 per cent of all Kenya’s cases – implying widespread HIV prevalence in the early 1980s at least. By 1993, prevalence at antenatal clinics in Kisumu, the regional capital, was 20 per cent and rising quickly.53 In the absence of detailed analysis, the best explanation of this epidemic suggests a combination of circumstances fostering disease elsewhere but seldom joined in one place. One was participation in lakeshore fishing culture. ‘The beaches attract a continual inflow of people,’ it was reported: ‘young men in pursuit of an easy cash income and women following the men. They live outside the traditional social structure and subsistence farming households, and drinking, casual sex, theft, HIV/AIDS and high death rates among young men are common.’ Nearly half the adults in these areas may have been infected by the early 2000s.54 Equally vulnerable were young people with casual jobs on sugar plantations and especially on the fringes of the transport industry, for Nyanza straddled the trans-African highway and had its own motor transport network. Its dense rural population, closely linked to the urban focus of infection in Kisumu, bred rural prevalence levels among adults reaching 30 or 40 per cent in the early 2000s, while scarcity of land and lack of rural opportunity perpetuated migration to Kampala, Nairobi, and workplaces throughout Kenya, where Nyanza people often had exceptionally high rates of HIV.55
The social organisation of the Luo people also contributed to the epidemic. One study attributed over half their infection to the fact that some 90 per cent of Luo men, unlike most Kenyans, were not circumcised.56 Their society was strongly patriarchal. In interviews at clinics in Kisumu in 2000, with Luo forming 81 per cent of those questioned, men reported unprotected sex with an average of 11.2 partners, women with 2.5. It is not clear whether these women included sex workers, but they numbered an estimated 1,400 in Kisumu in 1997–8 and 75 per cent of them were HIV-positive.57 Many were probably divorced or separated women with few other opportunities in Luo society. Luo themselves saw the epidemic as only the culmination of a century of economic decline and social disintegration, focusing particular attention on their custom of inheriting widows (and hence, supposedly, the virus that killed their husbands) and on alleged youthful promiscuity. One study in the rural Asembo area in 2004 showed that 33 per cent of boys and 22 per cent of girls under fourteen years of age claimed sexual experience, which had probably been common among youths in the past but had taken non-penetrative forms. A survey of women in Kisumu in the late 1990s found HIV infection only among those who had engaged in premarital sex.58 Female prevalence there rose from 8 per cent at age 15 to 29 per cent at age 17, at which age only 2 per cent of men were infected. Of every five people with HIV, three were women.59 The connection between gender inequality, sexual behaviour, and vulnerability could scarcely have been stronger.
Except, perhaps, in Ethiopia. In its origins the Ethiopian epidemic differed from those elsewhere in eastern Africa, but in most other respects it was, despite the country’s distinctive history, surprisingly similar, especially in the unsuspected early spread of heterosexual infection arising from sexual exploitation of women. The problem in Ethiopia, however, is not, as in Nyanza, why an extensive epidemic took place, but rather, as in pre-genocide Rwanda, why the epidemic was not more extensive. This may seem paradoxical, for in the early 2000s about 1,500,000 Ethiopians had HIV. Yet that implied a prevalence in those aged 15–49 of 4.4 per cent, only half the proportion in Tanzania and two-thirds of that in Kenya.60
One reason restricting the epidemic was that HIV reached Ethiopia somewhat later than the other eastern African countries. The first two cases were diagnosed in Addis Ababa in 1986. Retrospective tests on stored blood revealed one case in 1984 and another in 1985, but none in earlier specimens. Analysis of the diversification of the