In just a few years, heterosexuals will outnumber homosexuals as victims of the fatal acquired immune deficiency syndrome. This is only one of several conclusions reached in a recent internal Central Intelligence Agency medical report that we have obtained.

The CIA report predicts that in the 1990s, the growing numbers of heterosexual AIDS victims will surpass the declining incidence of AIDS in the homosexual population. The reason? Homosexuals will change their high-risk sexual patterns.

The CIA experts explain why the numbers of homosexual AIDS cases will decline as safe sex practices become more prevalent: Many who are already infected will die.

Interestingly, the CIA says that "AIDS probably originated as a heterosexual disease, and it was only by chance that the homosexual community bore the brunt of the initial impact."

Today, AIDS victims are spread through the population in a statistical pattern that has not changed much since the disease first surfaced: 73 percent are homosexual and bisexual men, 17 percent are heterosexual intravenous drug users, 4 percent are Haitians living in the United States and about 1 percent are hemophiliacs.

The CIA report also lists the "disturbing but constant percentage of heterosexuals that cannot be classified as belonging to any high-risk group, (1 to 3 percent)."

Recent reports that mosquitoes might be carrying AIDS were dismissed by the CIA. It would take 2,800 bites by a mosquito infected by the AIDS human immunodeficiency virus (HIV) "to deliver a sufficient virus load to pose even a theoretical threat," the report says. "In fact, there is no evidence that mosquitoes are able to transmit living virus."

The CIA passed on to its employes information from the Centers for Disease Control in Atlanta that other insects, especially African bedbugs, cannot transmit AIDS to humans, either.

Mosquitoes and other bugs were rejected as an AIDS threat in part because "there are virtually no unexplained cases of AIDS in the 10- to 14-year-old age group, a group commonly exposed to mosquitoes and bugs. Of 26 cases of AIDS in this age group, all contracted their disease from blood or blood-product transfusions or were assaulted by an AIDS carrier," according to the CIA report. In another study of 62 children, ages 5 to 15, 61 fit into "established risk categories" and the remaining one case was still being investigated.

The CIA predicted, in effect, that AIDS will inevitably drive up insurance rates as the medical costs of caring for its victims goes through the ceiling.

"By 1991 the cost of AIDS care will surpass the medical costs of either breast cancer or lung cancer, and the time lost and money spent will exceed the present Medicaid budget by 100 percent, over $66 billion," the CIA observed.

In its eight-page report to its employes, the CIA attempted to dispel some fears. "AIDS does not appear to be spread through the air. You will not contract it in a crowded subway, though you may catch tuberculosis there."