The mother of a 2-year-old child infected with the AIDS virus has herself become infected after repeated contact with the boy's blood and body fluids while caring for him at home, the federal Centers for Disease Control reports in a bulletin to be published today.

The case is the first report of a parent acquiring the virus from a child, and the first case in the United States in which an individual apparently was infected through external contact with blood or contaminated fluids, rather than by injection of blood or sexual contact. The CDC reported that a similar case apparently has occurred in England.

The CDC's experts on acquired immune deficiency syndrome said that because details of the case were highly unusual, it does not signify a heightened risk of contracting the virus for family members or health workers caring for AIDS patients, provided they follow recommended precautions.

"In no way do we think this represents some kind of casual contact transmission. It is an unusual case," said Dr. Harold Jaffe, chief of the epidemiology branch of the CDC's AIDS program.

According to the report published in the CDC's weekly bulletin, the child spent 17 of his first 24 months of life in hospitals because he was born with a serious intestinal abnormality. He was fed through a permanent intravenous tube and through a feeding tube passing from his nose to his stomach. Because of his intestinal disorder, he also had to wear a plastic bag on his abdomen to collect stool.

While caring for him at home, the boy's 32-year-old mother performed tasks that included drawing blood from his intravenous catheter, removing intravenous lines and changing stool collection bags and nasal feeding tubes. She did not wear gloves or routinely wash her hands after these activities, the report said.

Last May, a blood test on the child showed evidence of exposure to the HTLV3 virus, which causes AIDS, and the exposure was traced to a transfusion a year earlier with blood later found to be contaminated by the virus. The blood had been transfused before widespread screening of donated blood for the AIDS virus became available.

A test of the mother's blood last October indicated that she, too, had become infected with the virus. She could recall no incidents of needle-pricking while caring for the boy, and had no other risk factors for acquiring the infection. Neither she nor the child has developed symptoms of AIDS, the report said.

Jaffe said the case does not invalidate recent studies showing no risk of infection among family members of AIDS patients during routine household contact.

"Though it does involve an infant and mother, it really is much more a case that occurred while delivering health care," he said. He added that the mother "really did not take any precautions at all."

He said the CDC recommends that all health workers wear gloves while handling blood or secretions that might contain blood, and when touching mucous membranes, such as the inside of the mouth. He said the same recommendation applies to those caring for sick individuals at home, and should be followed whether or not a patient is known to be infected with the HTLV3 virus.

As of Feb. 3, 17,001 AIDS cases have been documented in the United States, with 8,801 deaths, the CDC reported.