The history of the AIDS epidemic has been one of continuous controversy over points such as who first discovered its viral roots, how the infection made the transition from Africa to North America, and why did it spring, apparently from nowhere, 30 to 40 years ago.

Nicholas Regush, in his book “The Virus Within: A Coming Epidemic,” relates how Robert Gallo of the National Institute of Health and Luc Montagnier of France’s Louis Pasteur Institute waged a bitter debate over the discovery of the HIV-1 M virus. This is the virus responsible for most AIDS cases in the western world. In the end, Gallo and Montagnier were listed as “co-discoverers” of the HIV-1 virus.

Even the now widely accepted cause of AIDS as being the HIV-1 virus is not accepted by all researchers. Peter Duseberg, a microbiologist at the University of California at Berkeley, has been making the case since 1986 that AIDS is caused by toxic factors in the environment. Regush says that Duseberg even implicates AZT, the first drug approved for AIDS treatment, as being involved. Duseberg believes that people who tested positive for the HIV virus would never have developed AIDS if they had not been given AZT.

Mirko Grmek, in his book “History of AIDS,” says that three possible routes of AIDS from Africa to the West have been proposed: Haiti, Cuba and the Peace Corps. More than 10,000 Haitians worked in Zaire during the early 1960s, picked up the virus, and emigrated to the United States after returning from Africa. The Cuban connection involves soldiers who were sent to fight civil wars in Angola and then-Zaire (now the Congo) from 1972 to 1977. Proponents of this theory say the virus could have been brought to the United States when Castro sent many undesirables to this country in 1977 and 1978.

The Peace Corps’ involvement could come from the large number of volunteers sent to Africa in the decade preceding the AIDS epidemic’s emergence. Grmek says all three scenarios have strong advocates and the debate is still going on. Grmek also looks at the origins of AIDS and mentions two of the most fanciful suggestions. An American physicist Ernest Stirnglass maintains that the AIDS form of a previously harmless virus came about through a mutation caused by fallout from atomic bomb testing.

The Soviet Union had a more sinister scenario, hinting in 1985 that AIDS resulted when the HIV virus escaped from a U.S. biological weapons lab. While these theories were dismissed out of hand, a third, and more plausible, AIDS origin theory has only recently been shown to be wrong.

The generally accepted theory for the origin and spread of AIDS is given by Jon Cohen in the Sept. 15, 2000, issue of Science. Called the “natural transfer” theory, it proposes that native hunters became infected with the SIVcpz virus, a virus closely related to the human HIV virus, through the hunting and handling of its chimpanzee hosts. Species jumping by viruses has been documented as have mutations similar to that converting the SIVcpz primate virus into the human HIV virus. There would be an extended period of time when only a few people would be HIV-positive, but then effects of urbanization, such as dirty needle use and increased population mobility in Africa and beyond, caused the AIDS epidemic to explode on the scene.

This “out of Africa” theory was quickly challenged by one implicating the oral polio vaccination (OPV) program carried out in Africa during the late 1950s. The OPV-AIDS hypothesis was first proposed by Tom Curtis in the March 19, 1992, issue of Rolling Stone magazine and then by Ed Hooper in a massive 1999 book entitled “The River: A Journey to the Source of HIV and AIDS.” The basic premise is that between 320,000 and one million Congolese children were given oral polio vaccine between 1957 and 1959. Hooper says that Hilary Koprowski of Philadelphia’s Wistar Institute, where the vaccine was produced, used chimpanzee serum contaminated with SIVcpz that then mutated into the human HIV virus. Koprowski maintained that only monkey tissue, which does not carry the SIVcpz virus, was used.

In an effort to resolve the issue, Britain’s Royal Society held a conference last year at which several labs were chosen to examine the vaccine to see if it bore traces of SIVcpz or chimpanzee DNA. Recently published results strongly discount the OPV-AIDS hypothesis.

Hendrik Poinar et al, in the April 27 issue of Science, reporting on their search for primate DNA in 40-year-old samples of the vaccine, found monkey, but not chimpanzee, DNA, which supports Koprowski’s claim. Three other papers, all published in the April 26 issue of Nature, had similar results. Two groups tested the vaccine for both chimpanzee DNA and the presence of HIV precursor viruses, ie SIVcpz, and found no evidence of either. The third group did a lineage study that showed HIV was present in humans well before the late 1950s. This agrees with the findings published by Bette Korber et al in the June 9, 2000, issue of Science estimating that HIV appeared in humans as early as 1931.

All in all, at least one controversy surrounding the origin of AIDS has finally been laid to rest.

Clair Wood taught physics and chemistry for more than a decade at Eastern Maine Technical College in Bangor.