Another possibility is that HIV doesn't have anything to do with AIDS. This is what Peter Duesberg of UC Berkeley has been saying for five years: that HIV doesn't attack the immune system, doesn't cause AIDS, and is in fact harmless. A professor of molecular biology, Duesberg is one of the world's leading experts on retroviruses. I called him at his Berkeley lab and asked what he thought of the news from Amsterdam, and the possibility that we may now have one more lethal virus to worry about.

"How many different viruses are we going to have that all evolved in the last ten years and all cause the same disease?" Duesberg asked. "Viruses have been around for billions of years and now they're coming out for the latest AIDS conference."

Duesberg is a member of the National Academy of Sciences and was the first to map the genetic structure of retroviruses. He is not popular with the National Institutes of Health, the government agency that has been funding and policing AIDS research for the last decade. For years he was supported by an NIH "outstanding investigator" grant, but after he attacked the HIV theory of AIDS, his grant was cut off.

Down the hall from Duesberg at Berkeley's Stanley Hall is the lab of Professor Harry Rubin, another skeptic. He also believes that HIV has not been shown to be the cause of AIDS. I spoke to Bryan Ellison, a doctoral candidate with Rubin. Retroviruses have never been observed to kill cells, he told me. If you microscopically examine healthy cells in a dish, and a virus such as polio is added to them, the virus multiplies inside the cells and bursts them open in a matter of hours. Soon you can see nothing but "debris and garbage and dead cells," he said. But if you put HIV, or any other retrovirus, into the same dish with healthy cells-an environment where the body's immune system cannot interfere-the cells just sit there and continue healthy growth.

Knowing this, Duesberg and Rubin were suspicious when HHS Secretary Margaret Heckler announced in 1984 that a retrovirus, HIV, was the cause of AIDS. What was the evidence for this? Correlation. Where there was AIDS, there was HIV. "There is no AIDS without HIV," James Curran, AIDS chief of the Centers for Disease Control, has said.

Duesberg responds: AIDS is defined as any of 25 existing diseases in the presence of HIV. Therefore the correlation between HIV and AIDS is 100 per cent by definition. At an "alternative" AIDS conference in May, Duesberg illustrated the point this way: TB+HIV=AIDS. But TB - HIV=TB. "It was a great triumph" for the AIDS establishment to take these different diseases "and put them all in the same uniform labeled AIDS," Duesberg said.

Until the latest flurry of reports from Amsterdam, patients with AIDS-indicator diseases but without HIV were not counted as AIDS cases. For reasons that are not clear, a decision has now been made to play up the "discovery" of such cases. There may have been thousands of them already. Robert Root Bernstein, a professor of physiology at Michigan State University, says that such cases were reported in the medical literature in the mid 1980s. And according to Duesberg, in about half the AIDS cases enumerated so far, patients were never actually tested for HIV. They were presumed to be positive but may not have been.

I phoned the Centers for Disease Control in Atlanta and asked what they thought of Duesberg's ideas.

"Up to now we have said-and we still say-that HIV causes a majority of AIDS cases," said Chuck Fallis, a press officer. "The jury is still out on the new virus-whether it actually causes the other AIDS cases."

"Nothing specifically on Duesberg?" "No."

What was once "all" has now become "a majority."

"You don't ever have polio without polio virus," Duesberg says. "A hundred cases can support a theory, but it only takes one to destroy it."

Something has been attacking the immune system, he agrees. The T-cells of AIDS patients do dwindle away, and there has been an increase in such opportunistic diseases as pneumocystis in the past decade. But HIV has never been shown physically to attack T-cells. The virus in fact is very difficult to find, even in patients dying of AIDS. Usually only antibodies can be detected-which is why an antibody test is used for HIV. Indications are that HIV is swiftly neutralized by the body's defenses. Yet it is said to kill after a ten-year (average) latency period. This has been lengthened to account for the failure of AIDS cases to keep pace with projections. Another oddity: researchers still have no "animal model" for AIDS. Over one hundred chimps have been infected with HIV since 1985 -- and the virus does "take," or replicate within them-but none has yet come down with AIDS.

Routine testing of army recruits shows the HIV-positive percentage of the population has remained constant since 1985, and AIDS remains largely confined to risk groups-homosexuals and drug-users. Neither finding is consistent with a new virus spreading in the population.

Duesberg goes further and claims that drugs are the real cause of AIDS. If he's right, the emaciated patient in the AIDS ward corresponds to the emaciated junkie in the opium den. One-third of AIDS patients are admittedly intravenous drug users-covering about 75 per cent of heterosexual AIDS cases. The real figure is probably higher: drug use is illegal, and no doubt underreported. Duesberg adds that homosexuals from the "bathhouse culture" are (or were) heavy drug users (including non-injection drugs such as "poppers"). In the course of their encounters they tend to pick up whatever is going around, including HIV and other germs. But he says that HIV itself is a harmless "hitchhiker"-a marker for risk behavior, as the scientists say.

It's the same with needle-sharers. They pick up HIV, but, says Duesberg, it's the drugs that are killing them, not the bugs. This would explain why over 80 per cent of AIDS patients are male (males consume over 80 per cent of psychoactive drugs); and why the sexually active general population that is not addicted to drugs does not get AIDS (at a time when venereal disease is spreading). On Duesberg's theory, needle-exchange programs are worse than useless. Many homosexuals, incidentally, are enamored of the viral theory of AIDS. ACT-UP member Robert Rafsky, who "confronted" Bill Clinton in the New York primary, thinks that HIV "cloaks AIDS activists in nobility." Duesberg's position is politically unpopular. As he says, if drugs cause AIDS "you are responsible for your health."

Duesberg also makes the following claims: there are no cases in the medical literature of health-care workers contracting AIDS through accidental needle-stick. In a footnote to its latest AIDS report, the CDC says there have been four such cases, but they have not been identified or described. There are a few disputed cases in the courts "and they want their money," Duesberg says. By contrast, about 15,000 cases of needle-stick hepatitis infection are reported every year.

About 75 per cent of the 20,000 U.S. hemophiliacs are HIV-positive, but there has still not been a properly controlled study of them. Do those with HIV come down with more AIDS diseases, or die sooner, than those without? It has been found that hemophiliacs in general are living longer than ever, even though three-fourths are now infected with the "deadly virus" and virtually all of these have been infected for eight years or more. Since the relevant data are already in place and await only statisticians, perhaps NIH could spend some of its research billions on a hemophiliac study.

"There is not a single controlled epidemiological study to confirm the postulated viral etiology of AIDS," Duesberg wrote in 1990. True? San Francisco's Project Inform recently put out a discussion paper, very critical of Duesberg, referring to "studies" comparing HIV-infected homosexuals with uninfected controls with "similar patterns of drug use and frequency of sexual contacts." None of the latter came down with AIDS, apparently. These studies were not identified or footnoted, so I phoned Martin Delaney, the executive director of Project Inform, and asked for the reference.

His "source," it turned out, was a person, not a paper. He gave me the name of a doctor who is identified in Randy Shilts's book, And the Band Played On, as having helped persuade CDC a decade ago that AIDS was caused by a virus. I phoned him but so far haven't heard back.

Delaney seemed dismayed that journalists were interested in Duesberg. I mentioned the series of articles that came out recently in the (London) Sunday Times about Duesberg and his critics. "When the Sunday Times publicizes what Duesberg says," Delaney replied, paradoxically, "it has an obligation to ask, 'What is your source for this?' They don't apply skepticism."

I spoke to Neville Hodgkinson, the Sunday Times's science correspondent and author of the series. He said he had never checked anything so carefully before publication. He was concerned that there might be a study he didn't know about. "What was the response?" I asked.

"Anger and indignation, but no factual rebuttal," he said. "I've never seen anything like it." He was solemnly told that there is a "consensus" that HIV causes AIDS, and it shouldn't be challenged.

"HIV Causes AIDS: A Controlled Study," was the unsubtle title of a paper released at the Amsterdam conference. Here was the "long-awaited rebuttal to controversial UC Berkeley Professor Peter H. Duesberg," wrote the San Francisco Examiner. Like the New York Times, however, it has ignored the controversial professor. The study was of homosexuals in Vancouver, some of whom were HIV positive, some not. "Every case of AIDS occurred in people infected with HIV," according to Martin Schecter, the principal investigator. But according to Duesberg, the two cohorts "were not controlled for extent and duration of drug use." The "positives" had been doing drugs for years, apparently; the negatives either not at all or for a much shorter period.

Maybe, then, we don't have a study refuting Duesberg yet. If we don' t have one soon, we may have a major scientific scandal on our hands.*

Mr. Bethell is Washington editor of The American Spectator and a Media Fellow at the Hoover Institution.