The three other organ recipients are getting rabies shots and haven't displayed any symptoms. Doctors at the Centers for Disease Control and Prevention declined to speculate on their chances for survival.
"This case is so unique and atypical that we cannot make predictions," said Richard Franka, acting leader of the CDC's rabies team.
Dr. Matthew Kuehnert, director of the agency's Office of Blood, Organ, and Other Tissue Safety, said investigators don't know why doctors in Florida didn't test the donor for rabies before offering his kidneys, heart and liver to people in Florida, Georgia, Illinois and Maryland.
The man in Maryland who received the transplant died. The Defense Department said he was an Army veteran who had transplant surgery at Walter Reed National Military Medical Center.
A rabies test after a death can take four hours once the tissue reaches a lab in Atlanta, New York and California, Franka said. That's precious time, considering a donated kidney remains viable for less than 24 hours; other organs last for less than six.
The donor had seizures and encephalitis - a brain inflammation that can be caused by rabies - but those symptoms can also be caused by a variety of bacterial, viral and other more common conditions.
"Rabies is very unusual and it can look like a lot of different things," Kuehnert said. "I personally can't say I would have been able to make the correct diagnosis had I been there, without knowing what I know now."
Federal rules require organ banks to disclose "any known or suspected" infectious conditions that might be transmitted by the donor organs.
"We don't know exactly what was communicated, but from what I understand of the patient workup, they did not find any evidence of an infection," Kuehnert said.
The donor died in September 2011 at a Florida medical facility. His cause of death was listed as encephalitis of unknown origin, Florida Department of Health epidemiologist Dr. Carina Blackmore said.
He was a North Carolina resident who was training to become an aviation mechanic in Pensacola, Fla., when he got sick, Defense Department spokeswoman Cynthia O. Smith said.
A rabies expert unconnected to the case, Dr. Rodney Willoughby of Milwaukee, said the three other recipients have a strong chance of surviving since they haven't shown any symptoms.
Public and military health officials said they're trying to identify people in all five states who had close contact with the donor or the recipients, whose identities haven't been publicly disclosed. Those people might also need treatment.
In North Carolina, state health officials recommended vaccine for at least one of the donor's relatives, said Carl Williams, the state's top public health veterinarian. He said fewer than five family members from North Carolina visited the man while he was hospitalized in Florida.
"What generally happens in human rabies patients that are hospitalized is that there is a lot of close contact, not only from health care workers but from close family because the patient is going to die," Williams said. The disease can be transmitted by saliva from a kiss or tears wiped away, he said.
The CDC hasn't determined how the donor got the raccoon rabies virus that killed him and the Maryland man. Investigators found the virus in their brain tissue.
The Illinois transplant was performed at Northwestern Memorial Hospital in Chicago.
The CDC said there has been just one other reported instance of rabies transmission by transplanted solid organs, a 2004 case in which all four recipients died after receiving tissue from an infected donor. There have been at least eight instances of rabies transmission through transplanted corneas, CDC spokeswoman Barbara Reynolds said.
"Human rabies is very rare in the United States, and so, of course, when we're talking about organ transplantation, very, very rare," she said. Rabies is diagnosed as the cause of just one to three deaths per year in the United States, she said.
The Maryland death was announced Tuesday by state health officials. State Public Health Veterinarian Katherine Feldman said doctors suspected before he died that he had rabies, and they knew about his kidney transplant, but considered a rabies-infected kidney to be a remote possibility.
The raccoon rabies virus has a typical incubation period of one to three months, although there have been other cases of longer incubation periods, the CDC said. In the United States, only one other person is reported to have died from a raccoon-type rabies virus.
After the four deaths in 2004, the U.S. Department of Health and Human Services created a committee within the federal Organ Procurement and Transplantation Network to look specifically at disease transmission. Last year, the government published guidelines for evaluating organ donors with central nervous system infections, such as encephalitis. If evidence suggested such an infection, "caution should be considered," the guidelines said.
The Health Resources and Service Administration, which oversees the transplantation network, said Friday that there is no government-approved test to screen organ donors for rabies. Therefore, donation professionals must review the person's medical and social history to assess potential risks.