AIDS Only Caught From Sex, Blood and Birth, Study Finds

Government researchers who have studied every case of AIDS reported since the epidemic began concluded Thursday that there are only three ways the disease is transmitted in the United States: through blood contamination, sexual contact and birth to an infected mother.

Despite theoretical concerns and anecdotal reports, there is no documentary evidence to suggest that the AIDS virus has been transmitted by saliva, tears, urine, eating utensils, vaccines, casual contact or insects, the U.S. Centers for Disease Control reported in the weekly Journal of the American Medical Assn.

The possibility that the virus can be transmitted through breast-feeding is still being evaluated, the center said.

“We have studied this for six years now, and if there were other ways HIV (the AIDS virus) was transmitted, we would have seen it,” said Dr. Kenneth Castro, a center epidemiologist. “Adults are getting this through sex or through sharing needles, and that’s about it.”

Castro said the 1,700 AIDS patients currently classified as having “no known risk factors” are not examples of mysterious AIDS transmission but of inadequately investigated cases. “If we take the time to look (for primary risk factors), we find them,” Castro said.

As of Feb. 29, 54,723 cases of acquired immune deficiency syndrome had been reported to the Atlanta-based center, and 30,715 people afflicted with the disease had died.

Of these cases, 34,687 were classified as having been acquired through homosexual contact, 9,473 through sharing of needles and 4,016 through one or both. In addition, 1,182 women and 987 men contracted AIDS through heterosexual sex with an infected partner, and 663 children were infected by their mothers, either in the womb or during birth.

Although 600 hemophiliacs and 1,415 others have contracted AIDS through contaminated blood products or transfusions, screening procedures have made the risk of more of these infections extremely low in the United States.

Inadequate Information

Noting concern over the high number of undetermined cases, Castro and his colleagues investigated 2,059 AIDS patients who were classified as having no recognized risk factors as of Sept. 30, 1987. No information could be obtained on 921 cases (due to death or refusal to be interviewed), and 32 of the AIDS patients turned out to be wrongly classified.

However, 825 of the remaining 1,138 patients acknowledged high-risk behavior in interviews and were reclassified. Of 281 patients who could not be reclassified, 178 were extensively interviewed and many admitted to either a history of sexually transmitted diseases (38%) or sex with a prostitute (34% of the men). These are not yet considered high-risk categories by the center, but they suggest that the patients may have engaged in other high-risk behavior, Castro said.

“We’re never going to be able to identify every case, because some people are going to deny engaging in some high-risk behaviors as long as there is a stigma attached to them,” he said. “But the fact that we were able to reclassify 72% strongly suggests that it is a lack of information, and not an unidentified mode of transmission, that is behind these cases.”

In a separate article, Dr. Alan Lifson, a former center researcher now with the San Francisco Department of Public Health, reviewed 11 separate studies and concluded none had found a link between AIDS transmission and saliva, tears or urine, despite the fact that the AIDS virus can be found there. Further, there was no evidence to suggest that the virus had been transmitted by vaccines, eating utensils, insects or any sort of non-sexual familial contact.

In another AIDS report in the AMA journal, researchers found that the risk of suicide among American men with AIDS is 66 times higher than among the general population.

The study, based on an investigation of all suicides in New York City in 1985, found that of 668 suicides, 12 were committed by men who had been found to have AIDS. The study said the likelihood of suicide among AIDS patients far exceeded that of people suffering other major illnesses, including cancer.

All of the AIDS patients had been diagnosed less than nine months before their deaths, and the findings should prompt physicians treating AIDS patients to “evaluate suicide risk . . . carefully,” the researchers said.

HOW AIDS VIRUS INVADES THE CELL

These two series of photographs, taken by the microbiology laboratory of Osaka Medical College in Japan, shows how the AIDS virus penetrates human cells. In Series A, an AIDS virus (1) sticks to the cells. In (2), the invasion begins, and in (3), the virus has broken through the cell wall. In Series B, the AIDS virus (1) , now inside the cell creates a hole (2), firmly establishing it deep within the cell (3).