West Nile virus transmission via organ transplantation and blood transfusion - Louisiana, 2008

Three years after the introduction and spread of West Nile virus (WNV) in the United States, transmission through blood transfusion and solid organ transplantation was documented in 2002. Within a year, these findings led to nationwide screening of blood donors for WNV. Although screening is extremely sensitive, current methods still do not detect all WNV-infected blood donations, and organ donors are not screened routinely. In October 2008, the Louisiana Department of Health (LDH) was notified of a heart transplant recipient with suspected West Nile neuroinvasive disease (WNND). LDH launched an investigation to confirm the diagnosis and determine whether the organ recipient's infection was derived from the organ donor or blood products the donor received before organ donation. The investigation concluded that two cases of probable transfusion-transmitted WNV resulted from a common blood donor; one infection resulted in WNND via an organ donor, and the other resulted in asymptomatic WNV infection via blood transfusion directly. This investigation also found that criteria used by the blood-screening laboratory to screen the implicated blood donation for WNV were less stringent than criteria used by other blood collection centers in the area. Use of the more stringent screening criteria might have detected the WNV and prevented the blood donation from being used. To increase the likelihood of detecting WNV-positive donations, blood centers should use the most sensitive screening criteria feasible and communicate frequently with nearby blood centers on screening results during times of high WNV activity in their geographic area. In addition, health-care providers should consider WNND as a possible cause of neurologic complications in patients after blood transfusion or organ transplantation.