NATION'S BLOOD SUPPLY INFECTED WITH WEST NILE VIRUS

[ The Atlanta Journal-Constitution: 9/13/02 ]

West Nile blood worries deepen

By M.A.J. McKENNA
Atlanta Journal-Constitution Staff Writer

Three more people may have contracted West Nile virus through blood transfusions, deepening concerns about the safety of the nation's blood supply, the Centers for Disease Control and Prevention said Thursday.

The discoveries bring the potential total to five cases in four states across 1,200 miles.

The patients live in areas where mosquitoes are spreading the virus, and there is no test that might distinguish how they were infected. But the CDC and the Food and Drug Administration have begun discussing actions the federal agencies might take to limit the risk of further spread, including temporary blood donation bans on certain geographic areas or groups.

"In none of these cases, at this time, is it considered proven that transfusion transmitted the virus," said Dr. Jesse Goodman, deputy director of the FDA's Center for Biologics Evaluation and Research. "At the FDA, we are very concerned about this. So is the CDC. We're preparing as if this could turn out to be a real problem and hoping that it will not be."

The CDC said Thursday that three patients in Mississippi, Louisiana and North Dakota who have been diagnosed with West Nile received transfusions in the weeks before they developed symptoms. The three are in addition to two other patients who may have acquired the virus via transfusion: a Mississippi woman who received 18 units of blood after obstetric surgery and a Georgia auto accident victim who received about 40 units of blood before dying Aug. 1.

Two people in Georgia and two in Florida received organs from the accident victim. All four were diagnosed with West Nile; one of the Georgia patients died, and the other three are recovering. Health authorities have concluded that the four organ recipients acquired the virus through their transplants but have been unable so far to say whether a mosquito bite or a transfusion infected the organ donor.

"A large number of West Nile virus infections as a result of mosquito bite are occurring in the United States," said Dr. Lyle Petersen, deputy director for medical science at the CDC's insect-borne disease lab in Colorado. "Recent receipt of a blood transfusion by a person with West Nile virus infection does not necessarily implicate the transfusion as the source."

The number of human cases of the virus has risen to 1,295, including 54 deaths, in 30 states and the District of Columbia.

Late Thursday, the Fulton County Department of Health and Wellness in Atlanta announced two more probable cases, a 50-year-old man who was hospitalized and released and a 75-year-old woman who remains in the hospital.

The CDC also confirmed a California woman who has not traveled outside that state has West Nile virus. The agency left open the possibility that the woman -- who lives near Los Angeles International Airport and works for an air-courier company -- might have been infected by a mosquito that flew onto an airplane in another state and flew off in California. Mosquitoes hitchhiking from Africa in airplanes are known to have caused scattered cases of malaria, known as "airport malaria," in the United States and Europe.

More cases of West Nile virus can be expected in coming weeks, the CDC said. Though the mosquito season has peaked in the South, the end is several weeks away in the Midwest. Mosquito-borne diseases are a danger until cold weather kills mosquito populations.

The three cases disclosed Thursday came to light as investigators followed up samples from donors whose blood was given to the Georgia organ donor and the Mississippi surgical patient. Health authorities would not disclose their location, age or gender, though they did note underlying health problems that would have made the patients more vulnerable to the virus.

Petersen said the accident victim received blood from 63 donors from several states, while the surgical patient received blood from 17. Suspect blood that remained on blood bank shelves has been impounded, he said.

CDC researchers including Petersen had put the risk of transmitting West Nile through transfusion at one to two infections per 10,000 transfusions. In the Mississippi investigation, however, the CDC obtained blood from 15 of the 17 donors and found viral material in three of them, a proportion the FDA's Goodman called "surprising."

The possibility of a stronger association between West Nile infection and transfusion is clearly troubling to health authorities, even though the link has not been proved.

"There is no single laboratory test that's going to tell you whether the person got it from a mosquito bite or from a transfusion," Petersen said. "It's not going to be a black and white situation. It's going to be like a court of law where the preponderance of evidence suggests that this is occurring."

Until last month, the spread of West Nile had never been linked to organ donation or blood transfusion. The virus has circulated in Europe and the Middle East for decades and has been known to be in the United States since August 1999.

Health authorities have emphasized that people who need transfusions or organs should still get them, because the risk of contracting the disease remains low.

That position is reasonable, said Dr. Harvey Klein, director of the department of transfusion medicine at the National Institutes of Health and past president of the American Association of Blood Banks.

"While it is biologically possible that West Nile virus can be transmitted by blood transfusion, there has not been a single case confirmed, and the likelihood must be very rare," he said. "The big risk to the American public in terms of West Nile remains mosquitoes."

The CDC, the FDA and blood-collection groups such as the American Red Cross are collaborating on studies that may clarify the risk from transfusion, Petersen and Goodman said.

If the link between West Nile infection and transfusion is strengthened by additional evidence, Goodman said, the FDA might consider measures such as temporarily refusing blood from areas where West Nile activity is high or from donors who shared characteristics that might make them high-risk,.

The risk, Klein said, is that such measures might further reduce a national blood supply that is already low.

"You have to look at the potential benefit balanced against any potential risk, and the risk is blood shortages," he said. "We have had intermittent shortages over the past year, and they have been increasing over the past month."

A U.S. senator suggested Thursday the rapid rise in West Nile cases might be traced to bioterrorism. Sen. Patrick Leahy, a Vermont Democrat who received an anthrax-laden letter in last year's bioterrorist attacks, said: "We have to ask ourselves: Is it coincidence that we're seeing such an increase in West Nile virus, or is that something that's being tested as a biological weapon against us?"

West Nile was once rumored to be part of Iraqi leader Saddam Hussein's biological weapons arsenal. The possibility of the virus being deployed against the United States was explored in a July 2000 report by the Senate Government Affairs Committee and judged "very unlikely."



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