Test: West Nile Virus (WNV) Antibody, IgM
West Nile Virus (WNV) is spread by mosquitoes. Clinical symptoms for WNV are non-specific and infections can only be diagnosed by means of laboratory testing. Laboratory diagnosis is generally accomplished by detecting WNV-specific IgM antibodies in the serum or cerebrospinal fluid (CSF). IgM antibodies are usually detectable from 3 to 8 days after onset of illness and persist for 30 to 90 days, (longer persistence has been documented.)
The enzyme immunoassay (EIA) test provides a sensitive and specific, semi-quantitative assay for the detection of IgM antibodies to WNV. Highly specific viral protein is used to detect the antibodies to WNV and limit cross-reaction with other similar viruses.