Donated Blood: West Nile Source?

Health officials have identified a new possible target in their fight against West Nile virus as it spreads across the country.

They say a woman may have gotten the virus through blood transfusions, and four people possibly became infected after receiving her organs following her death.

One of the organ recipients has died, and three were hospitalized with symptoms associated with West Nile, although tests to determine if they were infected with West Nile through the transplants are still being conducted.

"We've known for some time that there is a theoretical possibility that people can get this through blood or organ transplants," said Tom Skinner, a spokesman for the Centers for Disease Control and Prevention. "It's highly unusual but it's certainly possible."

So far this year, there have been over 600 confirmed cases of West Nile disease in the U.S., including 31 deaths. CBS News Reporter Paul Moniz quotes epidemiologists as saying that for each confirmed case, there could be as many as 200 people who are infected and show no symptoms. That means that theoretically, there could be thousands of people carrying the active virus.

American Red Cross spokeswoman Trudy Sullivan says points out that while no fast test exists to screen blood for West Nile, anyone showing symptoms of the virus would be turned away.

"Yes, the screening process doesn't cover everything, but if you've even got flu-like symptoms, you will be turned away," Sullivan said. "We have a number of different layers of safety."

Four people, who haven't been identified, may have been infected with West Nile after receiving the kidneys, heart and liver of a woman who died in Georgia in early August after a car accident, the CDC said.

Officials say the woman may have already been infected or may have gotten West Nile through blood transfusions in the emergency room.

The Atlanta-based CDC is trying to trace donors who contributed the transfused blood, the blood products made from the donations, and any other patients who may have received blood or blood products from the donations.

The Food and Drug Administration issued an alert to blood banks two weeks ago to exercise extra caution when screening donors, said Dr. Jesse Goodman of the FDA.

"We have been very active and tried to anticipate the possibility of something like this," Goodman said.

Three of the four patients developed symptoms of encephalitis, the inflammation of the brain and central nervous system, which is the most serious consequence of West Nile virus.

One of the four has died in Atlanta, said Dr. James Hughes, director of the CDC's National Center for Infectious Disease. Standard pathology tests from an autopsy confirmed the recipient had encephalitis. Tests are ongoing to see if the recipient was infected with West Nile, which causes encephalitis.

Another recipient from Jacksonville, Fla., showed symptoms of encephalitis Sunday, said Dr. John Agwunobi, the Florida Secretary of Health.

The 63-year-old man who may have gotten West Nile from a heart transplant was upgraded from critical to serious condition Sunday, said Evelyn Lichterman, an administrator at Jackson Memorial Hospital.

CDC officials say they're sure the man didn't contract the disease from a mosquito, said Mary Jo Trepka, epidemiology director with the county health department.

Samples from the four transplant recipients were sent to the CDC's lab in Fort Collins, Colo., Hughes said. Tests results are expected within the week.

There is no test yet that can quickly or accurately identify the presence of the West Nile virus. Patients are diagnosed based on their immune response to the virus.

However, researchers at the CDC are trying to find a way that will cut down the time from when infection occurs and when a response to the virus can be measured, the CDC said. It now takes about 15 days.

Officials say they remain optimistic that there is a low chance West Nile can spread through blood because there have been no confirmed cases to date.

There are also no known cases of person-to-person transmission of other diseases in the same family as West Nile called the arboviral encephalitides: St. Louis encephalitis, La Crosse encephalitis and Eastern and Western equine encephalitis.

However, there have been cases of other mosquito-borne diseases being passed by blood transfusion or transplant. Last year, a CDC review of blood-donation problems turned up 93 patients who contracted malaria after blood transfusions.

Cases have also been reported in which dengue, another mosquito-borne disease, was transmitted to a health care worker by a needle-stick and between siblings after a bone-marrow transplant.

Sullivan said the blood supply is safer than it's ever been, and that her organization is "focused on allaying any fears or concerns about the safety of the blood supply for both donors and recipients."

Every unit of blood donated goes through up to 12 tests to ensure patient safety, including tests for HIV and hepatitis C, Sullivan said.