How many of the human WNV cases are being confirmed by the CDC laboratories?
A. When WNV was first found in the United States in 1999, the CDC reference laboratory confirmed all human cases of WNV. Through a comprehensive, CDC-sponsored laboratory training program, most states are now able to perform the initial blood tests to identify IgM-antibody in the blood or CSF of suspect human WNV infections, and many state laboratories are also able to perform the more involved PRNT. The CDC reference lab is called upon for confirmatory testing by fewer and fewer states; although the increased activity of WNV still requires that many tests be performed at the CDC reference laboratory.
