RICHMOND, JAN. 4 -- Gov. Gerald L. Baliles, responding to an urgent appeal from public health officials, signed an emergency order today giving Virginia physicians the right to report to state medical authorities the names of patients who test positive for exposure to the AIDS virus.

Medical experts said the regulation, which coincides with the release of a study outlining the impact AIDS will have on Virginia, marks an important advance over a 1983 rule allowing doctors to report only known cases of the deadly disease to local health departments.

"The time is now ripe for this next step," said Dr. A. Martin Cader, the director of state Division of Communicable Disease Control, one of several agencies in the state health department that have made the fight against AIDS their "number one public health priority."

Under the order signed by the governor, a doctor may report the identities of persons infected with the human immunodeficiency virus (HIV), which causes acquired immune deficiency syndrome, or AIDS, when the physician needs a health department's assistance in counseling the patient or tracking down the person's previous sex partners.

AIDS is generally transmitted by sexual contact or intravenous drug abuse; a patient whose blood tests positive for antibodies to AIDS does not necessarily have the disease, but was exposed to the virus and could pass it on to others, experts say.

Virginia, which was the first state in the nation to offer testing and counseling services for AIDS victims at its 119 clinics for the treatment of sexually transmitted disease, joins only a handful of other states -- Missouri and Colorado among them -- in giving doctors the discretion to report cases of exposure to the AIDS virus.

Cader and other public health spokesmen stressed that the confidentiality of the test results would be guaranteed by the state health department.

They also said the governor's order would save them several valuable months by effectively bypassing the General Assembly, which opens its 60-day session of lawmaking next week.

"It is absolutely important that we intervene as quickly as possible to help curb the spread of this disease," Cader and other state health officials said in a new report on AIDS in Virginia. "The sooner we can give physicians the regulatory authority to report {positive} HIV antibody test results, the better we can accomplish this."

The report also said that of the 568 Virginians who were reported to have AIDS between January 1982 and last November, 316, or 56 percent, have died. If that rate continues, the cumulative number of persons to have contracted AIDS by 1995 will be 3,343. The AIDS infection rate will continue to be greatest in Northern Virginia, where new cases are increasing at twice the rate of those in central and eastern Virginia, the report said.

In addition to the toll in human life, the cost in dollars will be staggering, the report added. The cumulative costs of providing care for all persons with AIDS diagnosed between 1982 and 1995 will exceed $210 million.

"This disease will continue to have a huge impact on Virginia," the report said.