Probable transfusion transmission of West Nile virus from an apheresis platelet that screened non-reactive by individual donor-nucleic acid testing.

A probable case of fatal neuroinvasive TT-WNV was linked to an infectious apheresis platelet unit undetected by WNV ID-NAT. It is hypothesized that the suspect unit was collected early in the viremic period when viral RNA was below the limit-of-detection of the ID-NAT assay. Implementation of ID-NAT screening of blood donors has not entirely eliminated the risk of TT-WNV infections, which may best be addressed by pathogen inactivation technologies.