West Nile Virus

Issue
West Nile Virus is one of a group of disease-causing viruses called flaviviruses, which are spread by insects, usually mosquitoes. Most people infected with West Nile Virus do not exhibit symptoms, and some exhibit mild symptoms such as fever and headache. Those with severe symptoms of the virus can develop West Nile encephalitis, West Nile meningitis or West Nile meningoencephalitis. In 2002, evidence indicated that West Nile Virus could be spread through blood transfusion if a patient received blood from a donor infected with the virus.

Facts
The risk of contracting West Nile Virus through blood transfusion remains extremely low. The Red Cross and other public health officials reiterate that the benefits of blood transfusion outweigh the risks of contracting West Nile Virus.

There is currently no blood donor screening test for West Nile Virus, but the CDC, FDA and industry are working together to develop an appropriate test.

The many safety layers used to protect our nation's blood supply include carefully screening blood donors who may be experiencing symptoms of West Nile Virus. If a potential donor displays symptoms, such as fever and chills, they would be deferred from donating that day.

Currently, the Red Cross defers donors with West Nile Virus infection until 14 days after the condition is considered to be resolved and at least 28 days from onset of symptoms or diagnosis, whichever is the later date.

The spread of West Nile Virus is seasonal within the New York-Penn region, as mosquitoes do not typically survive during frost-producing temperatures.

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