title: Development and validation of an anti-N3 indirect immunofluorescent antibody test to be used as a companion diagnostic test in the framework of a "DIVA" vaccination strategy for avian influenza infections in poultry.
abstract: Avian influenza (AI) infections have become of growing importance both for animal and human health. Vaccination has become a recommended tool to support eradication efforts and limit the economic losses caused by this disease. The "DIVA" system, using a vaccine containing a heterologous neuraminidase to the field virus, has been shown to be an effective tool in increasing the resistance of birds to field challenge, preventing clinical signs and reducing viral shedding in the environment. The companion diagnostic test to the vaccine, however, has been only partially validated in the field against one subtype of neuraminidase (N1). The present paper presents the results of a full laboratory and field validation of the diagnostic test developed to detect antibodies to the N3 subtype of AI in vaccinated and unvaccinated chickens and turkeys. Antibody kinetic studies conducted in the laboratory have shown that antibodies to the N protein may be detected earlier than antibodies to the haemagglutinin. The data derived from this extensive validation trial indicate the excellent capability of this assay in detecting the presence of active AI infection at an early stage in both unvaccinated and vaccinated birds and the lack of interference with vaccine-induced antibodies.
authors.affiliation: OIE, FAO and National Reference Laboratory for Newcastle Disease and Avian Influenza, Istituto Zooprofilattico Sperimentale delle Venezie, Laboratorio di Virologia, Padova, Italy. gcattoli@izsvenezie.it
authors.forename: Giovanni
authors.initials: G
authors.lastname: Cattoli
authors.forename: Adelaide
authors.initials: A
authors.lastname: Milani
authors.forename: Francesca
authors.initials: F
authors.lastname: Bettini
authors.forename: Maria
authors.initials: M
authors.lastname: Serena Beato
authors.forename: Marzia
authors.initials: M
authors.lastname: Mancin
authors.forename: Calogero
authors.initials: C
authors.lastname: Terregino
authors.forename: Ilaria
authors.initials: I
authors.lastname: Capua
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D002645:Chickens; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect / Q000379:methods / Q000662:veterinary*; D007252:Influenza Vaccines / Q000276:immunology*; D005585:Influenza in Birds / Q000175:diagnosis* / Q000517:prevention & control; D009439:Neuraminidase / Q000276:immunology; D015203:Reproducibility of Results; D014422:Turkeys; D014611:Vaccination / Q000379:methods*
chemical_list: D000914:Antibodies, Viral; D007252:Influenza Vaccines; D009439:Neuraminidase