title: Evaluation and optimization of a commercial blocking ELISA for detecting antibodies to influenza A virus for research and surveillance of mallards.
abstract: The availability of a validated commercial assay is an asset for any wildlife investigation. However, commercial products are often developed for use in livestock and are not optimized for wildlife. Consequently, it is incumbent upon researchers and managers to apply commercial products appropriately to optimize program outcomes. We tested more than 800 serum samples from mallards for antibodies to influenza A virus with the IDEXX AI MultiS-Screen Ab test to evaluate assay performance. Applying the test per manufacturer's recommendations resulted in good performance with 84% sensitivity and 100% specificity. However, performance was improved to 98% sensitivity and 98% specificity by increasing the recommended cut-off. Using this alternative threshold for identifying positive and negative samples would greatly improve sample classification, especially for field samples collected months after infection when antibody titers have waned from the initial primary immune response. Furthermore, a threshold that balances sensitivity and specificity reduces estimation bias in seroprevalence estimates.
authors.affiliation: National Wildlife Research Center, Wildlife Services, Animal and Plant Health Inspection Service, United States Department of Agriculture, 4101 LaPorte Avenue, Fort Collins, CO 80521, USA. Electronic address: susan.a.shriner@aphis.usda.gov.
authors.forename: Susan A
authors.initials: SA
authors.lastname: Shriner
authors.affiliation: National Wildlife Research Center, Wildlife Services, Animal and Plant Health Inspection Service, United States Department of Agriculture, 4101 LaPorte Avenue, Fort Collins, CO 80521, USA.
authors.forename: Kaci K
authors.initials: KK
authors.lastname: VanDalen
authors.affiliation: National Wildlife Research Center, Wildlife Services, Animal and Plant Health Inspection Service, United States Department of Agriculture, 4101 LaPorte Avenue, Fort Collins, CO 80521, USA.
authors.forename: J Jeffrey
authors.initials: JJ
authors.lastname: Root
authors.affiliation: National Wildlife Research Center, Wildlife Services, Animal and Plant Health Inspection Service, United States Department of Agriculture, 4101 LaPorte Avenue, Fort Collins, CO 80521, USA.
authors.forename: Heather J
authors.initials: HJ
authors.lastname: Sullivan
mesh_terms: D000818:Animals; D000835:Animals, Wild / Q000821:virology; D000914:Antibodies, Viral / Q000097:blood*; D004372:Ducks / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D062665:Epidemiological Monitoring / Q000662:veterinary*; D009980:Influenza A virus / Q000276:immunology* / Q000302:isolation & purification; D005585:Influenza in Birds / Q000453:epidemiology* / Q000821:virology*; D012680:Sensitivity and Specificity; D016036:Seroepidemiologic Studies
chemical_list: D000914:Antibodies, Viral
keywords: ELISA; Influenza; Surveillance; Wild birds