Atlanta ? Government health officials confirmed Tuesday that the West Nile virus had killed one transplant patient and infected at least two others, raising concern it can spread through transfusions and other medical procedures. Federal officials said they were speeding development of a West Nile blood test.

Until now, the virus had been thought to be transmitted to people only through the bite of an infected mosquito.

Officials at the Centers for Disease Control and Prevention said the victim died in Atlanta after receiving an organ from a Georgia woman who was killed last month in a car accident.

Three other people also received organs from the woman. The CDC said two of them have the virus and have developed encephalitis, an inflammation of the brain. West Nile has not been confirmed in the third person, who is recovering from a milder infection.

Health officials said the organ recipients could have contracted the virus from mosquitoes, but it is unlikely. The cases are believed to be the first West Nile infections from a medical procedure.

No blood test exists to detect the virus, even in people who show symptoms. Instead, patients are diagnosed based on their immune response to the virus within about 15 days.

Coming up with a quick blood test is a priority, said Dr. Lester Crawford, acting commissioner of the Food and Drug Administration, which regulates the nation’s blood supply.

“We are discussing with the secretary possible strategies to stimulate the development of these tests,” Crawford said before meeting with Health and Human Services Secretary Tommy Thompson.

Even if a test is developed, health officials said they were skeptical that all blood would be tested for such a rare disease.

“On the list of things I’d be worried about going wrong in a blood transfusion, West Nile’s way down at the bottom,” said Dr. Louis Katz, president-elect of America’s Blood Centers, an association of independent community blood centers.

Many health officials say a practical screening test is months, maybe years, away, and the risk of catching West Nile through a blood transfusion is remote.