FRIDAY, Sept. 6, 2002 (HealthDayNews) -- Concerns about the unprecedented spread of West Nile virus across the nation continue to escalate as health officials investigate two possible cases of transmission of the virus through donated blood.
But without a West Nile screening test, and possibly years before one is available, blood banks say it's business as usual, and for most, that means following the same guidelines that apply to all viruses.
"With any viral infection that's running around, we check for symptoms and don't allow donations from people who are sick, appear sick, or don't pass the FDA screening guidelines, and we haven't changed that with the new West Nile cases," says Dr. Tim Peterson, medical director of The Blood Centers, which provide blood to more than 40 hospitals in the heart of mosquito country, New Orleans and the Gulf Coast.
Peterson says despite the heightened spotlight on West Nile, the disease has yet to prompt more alarm at blood banks than the occasionally severe outbreaks of influenza that strike.
"Whenever we have one of the influenza epidemics we get every couple of years, we have more deaths from those than we have from West Nile," he says. "And they impact the same groups of people -- the elderly, those with weakened immune systems, and the very young."
"The [West Nile] alert seems heightened by the spread by mosquitoes," says Peterson. "But the spread of the influenzas occur through even easier means -- close contact with someone, even shaking hands or someone coughing in your vicinity, and that affects a lot more people."
Still, suspicion of transmission of West Nile through blood transfusions has prompted a flurry of activity among public health officials. The concern was sparked earlier this week when the Centers for Disease Control and Prevention announced that four patients who received donated organs from a Georgia car crash victim with the West Nile virus themselves each came down with the disease.
One of the organ recipients has died from encephalitis, a serious complication of West Nile; two others have West Nile encephalitis, and the fourth organ recipient has the milder West Nile fever.
While the car crash victim may have contracted West Nile through the typical means of transmission -- a mosquito bite -- officials are concerned that the virus may have been transmitted through the donated blood from 63 donors she received in the two days before her death.
In investigating to see if other West Nile cases were linked to recent blood transfusions, officials say they are now looking into the case of a Mississippi woman who developed West Nile encephalitis following an obstetric surgery in July.
While the woman lives in a part of Mississippi heavily infested with mosquitoes and says she had received numerous mosquito bites prior to the operation, officials are also investigating the possibility that she contracted the disease through one -- or more -- of the 18 units of blood transfusions she received during her surgery.
As a precaution, remaining blood products from the donors in both the Mississippi woman's case and the Georgia car crash victim's case have been withdrawn and the donors are being contacted in order to be tested for West Nile.
The CDC is downplaying the risk of contracting West Nile through donated blood, saying the need for blood far exceeds the risk, and that so far, no risk has even been discovered.
"There is absolutely no proof at this point that West Nile virus transmitted by blood transfusions has occurred," says Dr. Lyle Petersen, deputy director of the CDC's vector-borne disease division. "This still remains a theoretical possibility."
The CDC stresses that while it's likely some people with West Nile will have received blood transfusions, recent receipt of a transfusion does not necessarily implicate the transfusion as the means of West Nile transmission.
While blood banks already screen donors for any kind of viral symptoms, West Nile, like most other viruses, has an incubation period in which the infection is present before symptoms.
"There's almost always that window between infection and detection of symptoms and actually, West Nile's window is believed to be relatively small -- between about three and 10 days," says Peterson of the blood bank center.
With current confirmed deaths from West Nile at 43 and another 854 people sickened by the disease, this year's outbreak is by far the worst in the since West Nile was first detected in the United States in 1999.
The disease has spread well into northern and western parts of the country that have previously never seen West Nile, and officials in California today reported a suspected case in a young woman that would be the state's first-ever human case of West Nile virus.
Cases have been largely concentrated in the south, but Illinois has surpassed Louisiana as the state with the highest number of West Nile deaths, with nine. Louisiana has eight, according to the CDC.
What To Do
Visit the CDC for much more information on West Nile Virus. You can also try the Illinois Department of Public Health.
