"Not an Easy Disease to Come By"

By George J. Church.

The public anxiety, even hysteria, touched off by AIDS is understandable, if lamentable. The disease was identified just over four years ago, and much about the ways in which it spreads remains obscure. No one knows, for example, why it strikes women and men in about equal numbers in Central Africa, where the disease appears to have originated, while in the U.S. only about 7% of the 13,000 victims identified so far have been women. There are theories but no proof. Nonetheless, a review of the facts establishes that public fears are vastly overblown. The ways in which AIDS is known to have been transmitted in the U.S. are few.

The AIDS virus, designated HTLV-III/LAV, has been detected in four bodily fluids: semen, blood, saliva and tears. But it has been found in saliva and tears only in small amounts, and not a single case of transmission by those fluids has been documented. Doctors cannot prove that this will never happen, but nearly all known cases involve contact with the semen or blood of an AIDS victim. Quite direct contact too: the virus can live only a very short time outside the human body. It does not linger on doorknobs, clothing, food, dishes, glasses, utensils or toilet seats.

Thus there has been no known case of infection by so-called casual contact: being in the same room with an AIDS victim, sharing a meal or a bathroom, being sneezed on, even hugging and social kissing. Members of families who have lived in intimate non-sexual contact with AIDS victims for many years have yet to produce a single documented case of the disease. No doctor, nurse, dental technician or other "health-care provider," to use the medical jargon, in the U.S. is known to have picked up AIDS from a patient. (A nurse in Britain who contracted the disease was accidentally pricked with a contaminated needle.) In fact, there are only four ways in which the disease is known to be transmitted:

1) By transfusions of blood or blood products. Only 1% of American men and 10% of women with AIDS were infected in this way, and the numbers are likely + to dwindle. All blood donated for transfusions is now being subjected to a test to detect exposure to the virus.

2) By sharing of needles among people who inject drugs into their bodies intravenously. An AIDS victim passes a needle to another drug abuser who uses it immediately; blood on the needle enters the second narcotics user's vein. Some 14% of the men and 53% of the much smaller number of women who have contracted AIDS in the U.S. got it this way.

3) By childbirth. A baby can be infected with AIDS in the womb or during birth, probably from the mother's blood. The number of cases so far is very small, about 130 (some 180 children in the U.S. have the disease), but unhappily it is likely to increase. More parents are sure to be exposed to the virus, and a possibly large percentage, who for some unknown reason never develop symptoms, can unwittingly pass the virus to their children. (Both women and men who are not victims of AIDS can be carriers.)

4) By sexual intercourse. This is far and away the leading method of transmission, and to explain why requires being explicit; too often the mechanisms have been obscured by ambiguous phrases like "exchange of bodily fluids" that may frighten more people than they inform.

The disease can be spread by heterosexual intercourse. The primary agent of infection is semen. Women get AIDS from infected men. They do not get AIDS from other women so far as is known. Men get AIDS from women far less frequently; indeed there is some debate as to whether they do so at all. The virus can be carried by a woman's blood, but whether it is present in vaginal secretions is still subject to investigation. Blood or vaginal secretions might enter a man's body through sores or other lesions. It is not certain whether open-mouth kissing can transmit AIDS; given the small concentrations of the virus so far found in saliva, it would seem to be what scientists call an inefficient method of spreading the disease.

A heavy majority, as much as 73% of all AIDS cases in the U.S., result from homosexual intercourse between men. The most prevalent method of transmission from man to man (and possibly from man to woman) is thought to be anal intercourse, which frequently results in ruptures of the rectum, through which the semen of an infected man can enter the blood of a male or female sexual partner. The swallowing of semen, by either women or men, is suspected but not proved to be a method of transmission.

None of this means that AIDS is not a serious menace to the general population. It surely is, if only because not enough is yet known about precisely how the syndrome is transmitted. Many ways in which AIDS might be transmitted can be hypothesized and not disproved. For example, suppose a child who had AIDS got into a schoolyard fight with one who did not, and they cut each other enough to bleed profusely. The uninfected child might get AIDS only if blood from the AIDS victim entered his body through a cut, which is unlikely but not impossible. As an extra precaution, some health authorities recommend that AIDS children who might bite or are incontinent be kept out of school, though urine, like saliva, has not been known to spread AIDS. Even the obvious injunction to avoid intercourse with an AIDS victim is not easy to follow. Up to a million Americans are thought to have been exposed to the virus, and the vast majority do not themselves know who they are; many may not develop symptoms for six years or so. Indeed, it is widely believed that people who harbor the AIDS virus are most likely to infect others before, not after, they exhibit obvious symptoms.

Even so, the known facts, while hardly comforting, provide no basis for hysteria. AIDS is not wildly contagious: a large portion, possibly even a majority, of the people who have been exposed to the disease will never get it. At highest risk are the most sexually active homosexual men. For people who do not come into close sexual contact with them, Stephen Schultz, assistant commissioner of the New York City health department, offers this moderately comforting summation: "AIDS is not an easy disease to come by. It is hard to get."

With reporting by Patricia Delaney/Washington and Joyce Leviton/Atlanta