Africa:Helen Epstein was doing post-doctoral work in molecular biology in California when the moment of clarity struck. She asked her boss if perhaps they shouldn't be out helping the poor and the sick rather than examining the sex organs of a bug almost too small to see, writes Molly McCloskey.
Her boss replied that the poor and the sick will always be with us, though this was 1992 - nine years after HIV had been identified - and the sick were multiplying faster than seemed possible. As Epstein writes, the maps of the disease's spread across Africa would soon resemble "the field drawings of a conquering army".
Epstein (daughter of the late Barbara Epstein, a former editor and co-founder of the New York Review of Books) quit her job and travelled to the Ugandan capital, Kampala to work on an Aids vaccine project. At the time, one-third of adults in Kampala - and 18 per cent of adults countrywide - were HIV positive, the highest national infection rate yet recorded.
What Epstein didn't know was that while she was there, the HIV rate in Uganda was already declining, even as it soared across southern and east Africa. Between 1992 and 1997, it fell by 60 per cent in southern Uganda. This happened without flashy media campaigns or legions of international experts. Condoms weren't even widely available until the mid-1990s; condom advertising was banned by the Ugandan government until 1994.
Much of Epstein's gripping book focuses on what happened in Uganda, on why such a response has been slow to emerge elsewhere in Africa, and on how its potential has been undermined by a variety of forces, not least an evangelical revival that is helping to limit the discourse on HIV to one of "good" and "bad" behaviour. Africa, as Epstein notes, has become the battleground for another cold war, this one moral rather than ideological.
Two questions about HIV are explored at length in The Invisible Cure. The first concerns its origins and why it exploded when it did. Epstein discounts the theory put forth by Edward Hooper in his 1999 book The River: A Journey to the Source of HIV and Aids (that HIV leapt from apes to humans during a lab accident in the Congo in the 1950s) and the natural transfer theory, which holds that Aids is an old disease that spread suddenly in the 20th century due to social upheavals. She cites the fact that large-scale population movements, wars and prostitution were all features of pre-20th century Africa and that, despite their acceleration in the last decades, no new HIV viruses have emerged since the 1950s.
Instead, Epstein explores the possibility that HIV was a once-harmless virus that mutated into a deadly disease after rapid "passaging" through human beings. When a virus mutates, it makes millions of copies of itself, and the immune system begins killing off the weaker copies. It has long been known that, through this process of natural selection, rapid enough passaging from person to person will result in a more pathogenic virus. Certain medical practices may have facilitated such passaging. In the Belgian Congo during the first World War, for example, six syringes were used to treat 90,000 people for sleeping sickness.
The second question concerns why southern and eastern Africa have been hit so disproportionately hard by HIV - 63 per cent of all persons infected with HIV live in sub- Saharan Africa; South Africa and Swaziland currently have HIV rates of 32-34 per cent. In contrast, the HIV rate in the US never exceeded 1 per cent. Even in Thailand, the infection rate peaked at about 2 per cent in the early 1990s.
Esptein agrees with the now widely held view that Aids is common in south and east Africa not because people there have so many sexual partners but because they tend to have a small number of concurrent long-term partners. This network of overlapping sexual relationships is - as opposed to serial monogamy - highly conducive to the spread of HIV, partly due to the fact that an individual is much more likely to infect another within the first few weeks or months of having been infected themselves.
In the largely Muslim countries of north and west Africa, where HIV rates are lower, women's sexual behaviour is tightly controlled and large-scale concurrency networks do not emerge. The widespread practice of male circumcision in Muslim countries is also significant; it removes mucosal tissue in the foreskin that contains cells with special receptors for HIV and is now known to cut HIV transmission rates by up to 50 per cent.
SO WHAT DID happen in Uganda? Epstein calls it "collective efficacy" - simply, the ability of people to join together and help one another. While most of Africa was ignoring or denying the Aids crisis, hundreds of community-based Aids groups grew up in Uganda in the late 1980s and early 1990s. They cared for the sick and for orphans and warned people about the dangers of casual sex. President Museveni mobilised Ugandan health experts, launching education and prevention campaigns that openly addressed traditionally taboo subjects and precipitated a profound shift in sexual norms.
Everyone was viewed as being at risk, so prevention was a shared responsibility. The "zero grazing" campaign gave men realistic advice: try to stick to one partner, but if you must have multiple partners, at least avoid casual encounters with prostitutes and bar girls. (The number of Ugandan men with multiple partners decreased sharply during this period.) Home-based care, which brought people into direct contact with sufferers, may have provided the emotional jolt necessary to move people beyond a cognitive understanding of risk and into behaviour change. Epstein likens the campaign to the activism of gay men in America in the 1980s.
Unfortunately, this compassionate and commonsense approach is being undermined in Uganda (and elsewhere) by a growing emphasis on abstinence and abstinence-only HIV-prevention programs. In 2004, the year Uganda's first lady, Janet Museveni, sponsored a March for Virginity in Kampala, her Uganda Youth Forum began receiving US funding to promote abstinence. The previous year she had travelled to Washington to tell congress that abstinence had been the key to Uganda's reduction of HIV rates ($1 billion was subsequently earmarked for such programmes in developing countries). Epstein argues that abstinence - as opposed to faithfulness and partner-reduction - had little to do with it, citing the fact that teen pregnancy rates in Uganda remained constant throughout the decline in HIV rates.
At the same time, according to Epstein, international aid agencies not of the evangelical persuasion - such as UNAIDS - were loathe to align themselves with the religious right or risk alienating African politicians and policy-makers (many of whom would themselves be in concurrent relationships) and thus, until recently, largely failed to address partner reduction.
THIS ACCESSIBLE AND intelligent book contains so much of interest that there isn't space to explore here. The links between variant strains of colonialism and country-specific reactions to the epidemic. How the spread of HIV in southern Africa has been abetted by "transactional" sexual relationships, which function as a (lethal) social security system for women in countries with weak social welfare institutions. The rape epidemic in South Africa. Thabo Mbeki's bizarre HIV policies. The mistaken application of western models of HIV prevention by international aid agencies in Africa.
Epstein places all these topics at the service of her core message, which is that when it comes to HIV prevention (and, to some degree, treatment) it is the small, the unglamorous, the locally owned - the "invisible" of the title - that can produce results. As William Easterly also argued in The White Man's Burden: Why the West's Efforts to Aid the Rest Have Done So Much Ill and So Little Good (which Epstein cites), the most ambitious and over-arching foreign aid package may be a tremendous waste of money. But, as the international aid community knows, it's difficult to programme for the invisible.
Molly McCloskey works for the UN Office for the Coordination of Humanitarian Affairs for Somalia, based in Nairobi. Her latest book is the novel, Protection.
The Invisible Cure: Africa, the West and the Fight Against Aids, By Helen Epstein.
Viking Penguin, 261pp. £16.99