A D.C. student exposed to the deadly AIDS virus has been barred by city public school officials from attending classes with other students but is receiving separate instruction at an undisclosed school, officials reported yesterday.

The child does not have acquired immune deficiency syndrome, but has an illness caused by contact with the AIDS virus through "blood products treatment," said city school and health officials. They refused to give the age or sex of the child or further details of the student's illness.

The child's parent reported to school officials that the student had contracted AIDS-Related Complex, which may develop into AIDS, D.C. Commissioner of Public Health Andrew McBride said in an interview. AIDS-Related Complex is caused by the AIDS virus.

"The child's blood test was positive for AIDS-Related Complex," McBride said. "This does not necessarily mean that the child has the virus, only that the child has been exposed to it." About 20 percent of all people with ARC "will go on to contract AIDS," he said.

Like the AIDS virus, the ARC virus is not transmitted through casual contact, he said. Officials said they are sure that there are no students in D.C. schools who have AIDS, but they don't know whether there are other students who have the ARC virus, McBride said.

At a news conference held in response to media reports about the student, School Board President R. David Hall said the student will be kept separate from other students until school and city health officials conduct further tests to determine if the child is likely to transmit the ARC virus to classmates through body tissues or fluids, by biting them, or exposing them to skin lesions.

"It is the right of every student to receive instruction," Hall said. "The student has been receiving instruction in school, but not in class with other students at this time."

AIDS, a fatal disease, destroys its victims' immune system, leaving patients vulnerable to other serious diseases, such as cancer.

Some school districts in the country have prohibited children with AIDS from attending classes. There is no D.C. school policy for handling children who have AIDS or who have been exposed to the virus, so officials are following many of the guidelines released last month by the federal Centers for Disease Control.

School officials expect to adopt a policy on AIDS children in the next few weeks, Hall said. A school board committee chaired by board member Eugene Kinlow (At Large) is scheduled to take action on a proposed set of rules at a Sept. 18 meeting, Hall said.

The CDC has recommended that school-aged children be allowed to attend school because there is no evidence that they can spread the disease through casual contact. But the center also suggested that cases be examined on an individual basis.

According to the CDC data, nationwide 183 youths under 18 have contracted AIDS. That number is expected to double within a year.

There are no statistics on the number of people who have ARC, CDC reported, but among the reported 12,932 AIDS cases, most victims contracted the disease through sexual intercourse, blood transfusions or by using intravenous drugs.

Hall said officials are sure that "no students attending classes in D.C. schools have AIDS" because doctors who treat AIDS victims are required by law to report such cases to public health officials. When a parent is reported to have AIDS and their children attend public schools, the children are examined and tested by city health officials, McBride said.

The CDC has reported that one child in the District has AIDS. The child is 13 or younger, but does not attend public school, officials said.

Doctors are not required to report ARC cases, McBride said.

"There will be other youngsters who will be identified as having" ARC, however the risk of them spreading it to others is "negligible," McBride said.