title: Development and evaluation of an N9-specific enzyme-linked immunosorbent assay to detect antibodies in duck and chicken sera.
abstract: A serological test for detecting N9-specific antibodies may be useful as a DIVA strategy to differentiate vaccinated from infected animals or simply for direct serological detection of infection with N9-subtype virus. The method currently recommended for the detection of antibodies against neuraminidase is neuraminidase inhibition (NI), which is a laborious method using toxic chemicals and has low sensitivity. The present study describes the development and validation of an N9-specific ELISA. Data obtained with this N9 ELISA were compared to those obtained with nucleoprotein-based ELISA, haemagglutination inhibition test using homologous antigen and NI assay. 785 sera from ducks and chickens were used, from flocks previously determined to be AI negative or from experimentally infected or immunized flocks. Sensitivity and specificity were evaluated, and a ROC curve and kappa values, which provide a comparison between methods, were calculated. The results obtained in this study indicate that the N9 based-ELISA is effective in detecting N9-specific antibodies with high specificity and with better sensitivity than the recommended NI method; using data from 177 common sera tested with N9 ELISA and NI assay both compared to NP-based ELISA, their specificity were evaluated at 93.6% and 91.5% respectively, and sensitivity at 90.8% and 39.2% respectively.
authors.affiliation: French Agency for Food, Environmental and Occupational Health & Safety, Ploufragan/Plouzané Laboratory, Avian and Rabbit Virology, Immunology and Parasitology Unit, VIPAC, French National Reference Laboratory for Avian Influenza and Newcastle disease, B.P.53, 22440 Ploufragan, France. Electronic address: audrey.schmitz@anses.fr.
authors.forename: Audrey
authors.initials: A
authors.lastname: Schmitz
authors.affiliation: French Agency for Food, Environmental and Occupational Health & Safety, Ploufragan/Plouzané Laboratory, Avian and Rabbit Virology, Immunology and Parasitology Unit, VIPAC, French National Reference Laboratory for Avian Influenza and Newcastle disease, B.P.53, 22440 Ploufragan, France.
authors.forename: Marie-Odile
authors.initials: MO
authors.lastname: Le Bras
authors.affiliation: French Agency for Food, Environmental and Occupational Health & Safety, Ploufragan/Plouzané Laboratory, Avian and Rabbit Virology, Immunology and Parasitology Unit, VIPAC, French National Reference Laboratory for Avian Influenza and Newcastle disease, B.P.53, 22440 Ploufragan, France.
authors.forename: Katell
authors.initials: K
authors.lastname: Louboutin
authors.affiliation: French Agency for Food, Environmental and Occupational Health & Safety, Ploufragan/Plouzané Laboratory, Avian and Rabbit Virology, Immunology and Parasitology Unit, VIPAC, French National Reference Laboratory for Avian Influenza and Newcastle disease, B.P.53, 22440 Ploufragan, France.
authors.forename: Véronique
authors.initials: V
authors.lastname: Jestin
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood*; D002645:Chickens; D019411:Clinical Laboratory Techniques / Q000379:methods*; D004372:Ducks; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D009980:Influenza A virus / Q000276:immunology*; D005585:Influenza in Birds / Q000175:diagnosis*; D009439:Neuraminidase / Q000276:immunology*; D012372:ROC Curve; D012680:Sensitivity and Specificity; D014730:Veterinary Medicine / Q000379:methods*; D014764:Viral Proteins / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral; D014764:Viral Proteins; C487630:NA protein, influenza A virus; D009439:Neuraminidase
keywords: Chicken; Duck; ELISA; Influenza; N9 antibodies