Detection of West Nile Virus Infection in Birds in the United States by Blocking ELISA and Immunohistochemistry

Abstract

A blocking ELISA targeting an immunodominant West Nile epitope on the West Nile Virus NSI protein was assessed for the detection of West Nile-specific antibodies in blood samples collected from 584 sentinel chickens and 238 wild birds collected in New Jersey from May-December 2000. Ten mallard ducks (Aftus plat!lrlry~fchos) experimentally infected with West Nile virus and six uninfected controls were also tested. The ELISA proved specific in detecting WNV antibodies in 9/10 chickens and 414 wild birds previously confirmed as positive by Plaque Reduction Neutralization test (PRNT) at the Center for Disease Control, Division of Vector Borne Diseases, Fort Collins, CO, USA (CDC). Nine out of the ten experimentally infected mallard ducks also tested positive for WN antibodies in the blocking ELISA, while 616 uninfected controls did not. Additionally, 1705 wild birds, collected in New Jersey from December 2000-November 2001 and Long Island, New York between November 1999 and August 2001 were also tested for WN antibodies by the blocking ELISA. These tests identified 30 positive specimens, 12 of which had formalin-fixed tissues available to allow detection of WN specific viral antigen in various tissues by WNV-specific immunohistochemistry. Our results indicate that rapid and specific detection of antibodies to WN virus in sera from a range of avian species by blocking ELISA is an effective strategy for WN Virus surveillance in avian hosts. In combination with detection of WN-specific antigens in tissues by immunohistochemistry (IHC) the blocking ELISA will also be useful for confirming WN infection in diseased birds.

West Nile virus infection of horses

“…Polyclonal and monoclonal antibodies to the NS1 protein have identified type-, complex-, and flavivirus-specific epitopes [34], which are mainly conformation dependant but are not virus neutralising. The NS1 protein of WNV has also been demonstrated to be antigenic and has been used as a diagnostic reagent in antibody capture ELISA procedures [44].…”

Vector-Host Interactions Governing Epidemiology of West Nile Virus in Southern California

“…Blood for antibody testing (0.2 mL) was dispensed immediately into individually labeled tubes containing 1.8 mL phosphate-buffered saline diluent with 0.75% bovine serum albumin, 28 kept on ice packs, and processed at the Orange County laboratory using a blocking enzyme-linked immunosorbent assay (ELISA) with a baculovirus-Kunjin epitope NS1 recombinant antigen and specific anti-West Nile NS1 monoclonal antibody 3.1112G, 29,30 on heat-inactivated sera. In addition, from August through October 2008, blood (~0.05 mL) from 84 free-ranging birds was added to individually labeled vials containing 1-mL Eagle's Minimum Essential Medium, frozen in the field on dry ice, and evaluated for the presence of active WNV in free-ranging birds by RT-PCR and inoculated Vero and porcine stable equine kidney (PSEK) cell cultures .…”

Pathology Associated With West Nile Virus Infections in the Yellow-Billed Magpie (Pica Nuttalli): A California Endemic Bird

“…Gibbs et al (2005) observed mononuclear leukocytosis and epicarditis/myocarditis most consistently in WNV-positive blue jays. Two other pathology studies found differing results with significant histologic lesions in freeranging crows in many organs except mild lesions in the brain (Steele et al, 2000) and more severe brain lesions in Purkinje cells and their dendrites as well as in neurons and glial cells (Jozan et al, 2003). Raptors exhibit WNV lesions in common with corvids, including myocardial inflammation and necrosis, lymphoplasmacytic encephalitis, and hepatitis (Ellis et al, 2007).…”