The world lost one of its great biologists in March when William Hamilton, who inspired a school of evolutionary thinkers, suffered a hemorrhage and died after returning to England from a trip to Africa. Tragic as it was, Hamilton's death could end up a footnote in a far more awful tale, one that may explain the origins of AIDS.
Hamilton, 63, devised the theory of kin selection, which explains altruistic behavior in nature. But what had brought him to the Congo, in Africa's war-ravaged, malarial heart, was something more prosaic and immediate: He was collecting chimpanzee shit around the city of Kisangani.
For if the chimpanzees around Kisangani carry a virus that is genetically related to the strain of HIV currently afflicting 50 million people, it will bolster the hypothesis that the global AIDS epidemic is a manmade curse, created by the mass administration of a polio vaccine that was tainted with a simian immunodeficiency virus in central Africa in the late 1950s. That would make it by far the greatest medical disaster of all time.
AIDS has spawned some weird theories with some surprising supporters -- South African President Thabo Mbeki, for one, has shown interest in the school of thought that AIDS isn't caused by the HIV virus. Hamilton, for his part, was sympathetic to the polio vaccine theory, although it has been rejected by most mainstream AIDS researchers, including a group that published results of its study in the journal Science on Thursday.
Researchers at Los Alamos National Laboratory used the supercomputer Nirvana, created to model nuclear explosions, to date the ancestry of the HIV bomb. Using a "molecular clock" calculation that estimates mutation rates of viruses, they found that the vaccine theory did not appear to fit with the dates. By comparing the similarity of gene sequences in HIV viruses, the Los Alamos team came up with 1930, give or take 15 years, as the year the original virus began mutating into the current killer strains -- not the late 1950s, the time the vaccine was supposedly administered.
The polio hypothesis, first presented in a 1992 Rolling Stone article, was explored in exhaustive detail by the English writer Edward Hooper in "The River: a Journey to the Source of HIV and AIDS." Since the book appeared last fall, it has generated some angry opposition from scientists who think it needlessly adds to African mistrust of Western medicine.
At the same time, it has enough plausibility to have engaged the interest of dozens and perhaps hundreds of researchers, many of whom will gather to discuss it in London in October at a two-day conference sponsored by the Royal Society.
"If there's a bottom line, it's that we need more data," says Simon Wain-Hobson of the Institut Pasteur in Paris. "Until then we should be careful not to draw hasty conclusions."
Hooper, who had worked in Africa as a U.N. employee and BBC reporter, spent nine years researching the 1,070-page book. The gist of his argument is that Hilary Koprowski, a world-famous polio researcher, unwittingly created the epidemic by squirting a vaccine contaminated with a simian immunodeficiency virus into the mouths of a million African children.
In some of these children, the ape virus created an infection that became AIDS, Hooper believes, and from these humble beginnings in the bush the disease spread to the world's four corners.
Hooper's case rests on circumstantial evidence, but lots of it. Perhaps most crucially, he shows that the sites of Koprowski's experimental vaccine campaign are tightly correlated with the first reported cases of AIDS several years later. Fully 64 percent of pre-1980 AIDS cases occurred in places where the Koprowski vaccine had been fed to children from 1957 to 1960, Hooper writes.
That correlation and other evidence, Hooper maintains, provides a far more plausible theory for the AIDS epidemic than the mainstream argument that HIV occurred "naturally" after one or more chimpanzees bit or otherwise mingled their blood with one or more hunters.
Hooper was not the first to suggest that medicine may have played a role in the AIDS explosion. Preston Marx, an American primatologist, has theorized that vaccine campaigns with dirty needles may have amplified the infection.
A paper published in an AIDS journal earlier this year by Jim Moore, a University of San Diego anthropologist, examines the idea that the disease arose as a result of the ruthless colonial practices of the Belgians and French, which uprooted thousands of Africans from their rural lives.
Forced labor campaigns funneled these men into common brothels and unhygienic immunization campaigns that could have amplified HIV infections. Africans on the run from press gangs, meanwhile, may have been driven to hunt bushmeat, thereby exposing themselves to the contaminated blood of apes.
HIV-1 Group M, the strain of HIV responsible for more than 99 percent of AIDS cases in the world, has been shown with genetic techniques to have its origins in a virus harbored by chimpanzees. That means that if Koprowski's polio vaccine carried the killer bug, the vaccine must have been cultured from chimpanzee kidneys.
But Koprowski, 83 and semi-retired, claims rhesus monkeys were used to culture the vaccine, and there are no records to confirm either version. A committee of leading AIDS scientists is currently examining samples of the original vaccine to look for traces of a virus, or of chimpanzee DNA, that might corroborate Hooper's theory.
Hooper is skeptical that those tests -- due to be published later this year -- will be meaningful. "Can we be confident that the vaccines being put forward by Wistar [the laboratory where Koprowski worked] were really the ones used in Africa? The likelihood is they will not produce very much in the way of conclusive results," he says in a phone interview from his Somerset, England, home.
Although the Science article doesn't state whether its hypothetical 1930 virus lived in the bloodstream of an ape or a human, to lead researcher Bette Korber, the results suggest that the ancestral sequence "occurred decades before the vaccination programs... For the [polio vaccine] hypothesis to be consistent with our analyses, at least nine genetically distinct viruses would have had to enter the human population through the vaccine."
In other words, as Harvard AIDS researcher Jerome Groopman wrote in a critical review of "The River" in the New Republic, "SIV [the simian version of HIV] has an alibi" -- the genetic fingerprints from chimpanzees do not match the earliest isolates of HIV, and it would take at least 20 years for the SIV to evolve into the first known sample of HIV -- from the Congo in 1959.
Hooper, however, argues that more than 80 pairs of kidneys were used to culture the vaccine Koprowski distributed. And if, as he believes, those kidneys came from chimpanzees, the chimps might have been infected with strains of SIV closer to the current strains of HIV, he says.
Koprowski's vaccine was developed on the outskirts of Kisangani -- then called Stanleyville. There were chimpanzees in cages there -- hundreds were used to test the vaccine for safety and potency. While Koprowski and his colleagues deny those chimps were used to make the vaccine -- as Hooper believes -- Hooper's theory would gain powerful weight if chimps living in the area today were infected with a simian virus similar to the HIV strain that's causing AIDS.
Which brings us back to Hamilton, who got interested in the thesis in the early 1990s, when Texas journalist Tom Curtis was working on an article for Rolling Stone.
Hamilton was an odd bird, by most accounts -- he had a striking mop of white hair and he towered over his peers, literally and intellectually. A beautiful writer and poor lecturer, he had a powerful temper but generally spoke in a near whisper. If you listened closely, though, you learned that Hamilton knew the names of most of the plants and animals in the world. He had also made a singular contribution to Darwinian thought by showing that altruism made evolutionary sense. (British scientist Richard Dawkins popularized this idea in his book "The Selfish Gene.")
"He was my mentor, he guided me," Hooper says. "He let me do most of the running but if I was going off the rails he'd call me back in."
Last June, Hooper and Hamilton traveled together to Kisangani, at the heart of the Congolese civil war. Hooper collected information about the polio research center while Hamilton collected feces from pet chimpanzees. Hamilton returned in January this year to collect urine and feces samples from wild chimpanzees and bonobos on either side of the Congo River. The materials are currently being tested.
"Kisangani is a very, very strange place, a very evocative place," Hooper says. "When we were there, the Ugandan army controlled the north bank of the river, with the Rwandese on the south bank, and the Congolese acting as second string. There was an atmosphere of tangible tension. All the imagery associated with the place, from Conrad to [V.S. Naipaul's] 'A Bend in the River' is extremely appropriate. The humidity, the slow-moving river, the mosquitoes that swirled in the river every time you opened the window."
On Hamilton's second trip, one of those mosquitoes gave him a bad case of malaria. An inquest after his death showed it was caused by an ulcer that may have developed as a result of a pill he took to fight his illness. And Hooper lost a scientific champion for his ideas, which British scientists have been generally quicker to entertain than their U.S. counterparts.
"The stakes are very high for the U.S. If this theory comes to be proved I don't think it will make anyone legally culpable, but it would mean the United States ... would need to rethink the way it is responding to AIDS in the Third World," Hooper says. "It's not a question of reparations -- Koprowski was trying to conquer the most dreadful disease of the day.
"But you know, shit happens. Bill Hamilton died. And to my mind, this polio vaccine is an example of a case in which humans scored an unintended own-goal."
A case, to translate from the British, of a very bad shot indeed.