(MADISON, August 13, 2004)—State health officials today announced that routine screening of blood donations has yielded a positive result for West Nile virus. Test results from the Blood Center of Southeastern Wisconsin indicate that blood donated by a Waukesha county resident has tested positive for the genetic material of West Nile virus. All of the blood and blood products from this donation were destroyed and did not enter the blood supply.

"This positive test result indicates that the screening in Wisconsin is successfully preventing the entry of West Nile virus infected blood into the blood supply," said Mark Wegner, M.D., M.P.H., Chief of the Communicable Disease Epidemiology Section of the Wisconsin Division of Public Health. "The benefits of receiving needed transplants and transfusions far outweigh the risk of West Nile virus infection." In addition, Dr. Wegner stressed that "there is absolutely no danger of contracting West Nile virus by donating blood."

The individual has not reported any symptoms, as is the case with most people infected by West Nile virus. Only symptomatic infections meeting a case definition are classified by the Centers for Disease Control and Prevention (CDC), as having West Nile fever or West Nile encephalitis. Therefore, this is not considered a human case of West Nile virus related illness. To date there have been no confirmed human cases of West Nile virus illness in Wisconsin in 2004.

Blood banks have been screening blood donations for West Nile Virus since July 2003. In addition, blood banks will not take donations from people who have recently had a fever and headache. Once a blood donation is identified as positive for West Nile virus, the blood products are destroyed and the donor is notified and followed by health-care workers to determine if he or she becomes ill. Although it is possible to become infected with West Nile virus through blood transfusions and organ donations, in general these are very rare occurrences.