A Virus as a Rosetta Stone

By Claudia Wallis

AIDS cases increase, but new research shows some signs of hope

When the disease first appeared five years ago, it seemed an impenetrable mystery. The best minds in medicine could not explain the cause of acquired immune deficiency syndrome (AIDS) or why it mainly struck homosexual men, intravenous drug users, Haitians and hemophiliacs. Nor could they begin to cure it. Six months ago came news of a breakthrough: scientists at the National Cancer Institute (NCI) in Bethesda, Md., and the Pasteur Institute in Paris had discovered a virus that seemed to be closely related to, if not the cause of, the epidemic. The finding was hailed by Secretary of Health and Human Services Margaret Heckler as "the triumph of science over a dread disease."

It was not quite that. But in recent months, the virus has served as something of a Rosetta stone in the efforts to decipher the enigmas of AIDS. It has also made possible the development of a test that will detect evidence of the infection in donated blood, an important step toward preventing the spread of AIDS by transfusions. Last week, at the annual meeting of the American Association of Blood Banks in San Antonio, and at gatherings of AIDS-related groups in New York City and San Francisco, the new developments were the major topic of discussion. Finally, it appears, a few facts are emerging from the morass of fear and confusion.

The good news is that aside from 86 transfusion-linked cases, the epidemic has not struck the general population. But the bad news continues relentlessly for the four major risk groups. So far, 6,517 cases of AIDS have been reported to the Centers for Disease Control in Atlanta; 72% were in male homosexuals. The number of new cases this year is twice that of 1983 and probably will continue to double. Nearly half the victims have died, although the ultimate mortality rate may be 90% or higher.

The one ray of hope in this grim picture is the rapid pace of research with the newly identified AIDS virus. There is now little doubt that the viruses isolated by the Pasteur group and by the NCI team under Dr. Robert Gallo are the same microbe. They are, however, slightly different strains, "like two brothers," explains Jean-Claude Chermann of Pasteur. Though a few questions remain, most researchers are now convinced that the virus is indeed the primary cause of AIDS. The evidence is compelling:

> Virtually all AIDS patients have identifiable antibodies to the virus in their blood. These antibodies are almost unknown in the general population.

> Researchers have produced antibodies and even early symptoms of AIDS in chimpanzees by injecting them with the virus or with blood plasma from AIDS patients.

> The virus has been found in the blood, semen and saliva* of AIDS patients and patients with early signs of the disease; the finding is significant, since doctors have long suspected that the disease is spread by the exchange of body fluids, especially through anal intercourse and shared hypodermic needles.

Not everyone infected by the virus will develop AIDS. "There is clearly a spectrum of outcomes," says Jerome Groopman of Harvard Medical School. While some individuals will develop the full-blown syndrome, others will simply manifest the flulike symptoms of AIDS-related complex (ARC), a condition marked by swollen glands, weight loss and weakness. While no patient has been known to recover from AIDS, there is new evidence, according to Dr. Jeffrey Laurence of Cornell Medical College, that some ARC patients do get better.

Perhaps the most provocative new finding is that the vast majority of people infected with the AIDS virus have no symptoms at all, but may still be spreading the disease. Researchers have found antibodies to the virus or the virus itself in large numbers of gay men who appear to be healthy. Says Laurence: "There must be some mechanism for immunity that we don't yet understand." Curiously, the antibodies do not appear to ensure protection against the ailment.

By some estimates, at least 50% of gay men in San Francisco and New York harbor AIDS antibodies. As a result, they will register positive on the new screening tests, though probably less than 10% will develop AIDS. "We don't know what to tell people who are positive," admits San Francisco Public Health Director Mervyn Silverman. "It might lead people to conclude wrongly that they are doomed."

Gay activists also fear that information about the test results will fall into the wrong hands. Some are recommending a boycott of the test unless confidentiality can be legally guaranteed. "Besides being clinically useless, this test is identifying," says Dr. Stephen Caiazza, president of New York Physicians for Human Rights. "It tells your employer, your insurance company or landlord that you are gay or a drug abuser."

--By Claudia Wallis

* Though the saliva finding has created something of a scare, experts say there is little chance of spreading the disease by kissing or sneezing.