Atlanta ? A transplant patient contracted AIDS from the kidney of a living donor, in the first documented case of its kind in the U.S. since screening for HIV began in the mid-1980s.

It turns out the donor had unprotected gay sex in the 11 weeks between the time he tested negative and the time the surgery took place in 2009.

In a report Thursday on the New York City case, the Centers for Disease Control and Prevention recommended that organ donors have repeat HIV tests a week before surgery.

“The most sensitive test needs to be done as close as possible to the time of transplant,” said Dr. Colin Shepard, who oversees tracking of HIV cases for the New York City Health Department.

The CDC also said would-be organ donors should be told to avoid behavior that can increase their chances of infection.

Living organ donors in the U.S. are routinely tested for infectious diseases such as hepatitis and HIV. But the organization that oversees organ transplants in the U.S. does not have an explicit policy on when such screening should be done. That’s left up to transplant centers.

Because of patient confidentiality, health officials released few details about the donor, recipient, their relationship or the hospital where the transplant took place, except to say that it is in New York.

Neither the donor nor the recipient knew he or she had HIV until about a year after the transplant, according to the CDC report.

The recipient developed AIDS, perhaps because he or she was on drugs that suppress the immune system to prevent organ rejection, while the donor did not, health officials said. Both are receiving HIV treatment. Their conditions were not disclosed in the report.

“We don’t know how frequently this is happening and we need better surveillance,” said Dr. Matthew Kuehnert, a CDC official who co-wrote the report.

HIV infections in a donor or recipient may not be discovered until long after a transplant, and even then, patients and their doctors may not make the connection and report it, health officials said.

In this case, once health authorities were notified late last year, they spent months investigating whether the transplanted kidney was the source of the patient’s AIDS infection. Genetic analysis of the virus confirmed investigators’ suspicions.

For many years, transplant organizations focused heavily on screening organs taken from the dead, which accounted for the large majority of transplants. But kidneys from live donors are becoming increasingly common. In 1988, about 32 percent of kidney transplants came from live donors. By last year, it was more than 46 percent, according to federal data. Donors generally are relatives or friends.

About 88,000 people are on the kidney waiting list right now, according the United Network for Organ Sharing, a nonprofit organization that manages the nation’s organ transplant system for the federal government.