The Bay Area’s first human West Nile virus infection this season was discovered by Blood Centers of the Pacific (BCP), as part of its now-routine screening of blood donors.

BCP – which provides blood to 42 hospitals throughout the region – began testing its blood donors for West Nile virus in 2003. This case marks the first known human case this summer for the nine-county Bay Area region.

Most people infected with the virus are asymptomatic and do not become ill from it. However, the virus can be transmitted by blood transfusion to a vulnerable patient – such as a transplant recipient or elderly person – and prove fatal. Detecting the virus is critical in protecting patients’ health and also serves as vital information for county public health departments charged with monitoring and combating the virus.

So far this year, there have been approximately 12 other known cases of human infection in California, including most recently, in Los Angeles County. That infection was also discovered during routine screening of donated blood.

The West Nile screening was added in 2003 to the battery of tests conducted on donated blood and has been extremely successful in protecting the blood supply. Donated blood is also screened for HIV, hepatitis B and C, and syphilis, and a parasite infection called Chagas disease.

The test uses the latest testing technology called nucleic acid amplification technology or “NAT,” which looks for the genetic material of the virus, a method that’s much more sensitive than older antibody tests.

Blood Centers of the Pacific, the nation’s first community-based blood bank, is a nonprofit organization that serves hospitals throughout Northern California.

To donate blood, call 888-393-GIVE or visit www.bloodcenters.org.

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