title: Surveillance of Infectious Bovine Rhinotracheitis in marker-vaccinated dairy herds: Application of a recombinant gE ELISA on bulk milk samples.
abstract: Infectious Bovine Rhinotracheitis (IBR) occurs worldwide, requiring significant resources for eradication programs or surveillance purposes. The status of infection is usually detected by serological methods using the virus neutralization test (VNT) or enzyme-linked immunosorbent assay (ELISA) on individual sera. The gE DIVA (Differentiating Infected from Vaccinated Animals) vaccines approach, adopted in order to reduce the virus circulation and prevent clinical signs, have tightened the range of available methods for the serological diagnosis. Different gE blocking ELISA could be performed to detect specific antibodies in sera of infected or whole virus-vaccinated animals but with less sensitivity if applied to bulk milk samples, especially in marker-vaccinated herds. A new rec-gE ELISA was recently developed in Italy and applied with good performances on blood serum samples. The present paper focuses on the application of a rapid protocol for purification/concentration of immunoglobulin G (IgG) from bulk milk and on the use of the new rec-gE indirect ELISA. The study involved three different partners and 225 herds (12,800 lactating cows) with different official IBR diagnostic statuses. The diagnostic specificity of the method was demonstrated closed to 100% while the diagnostic sensitivity was strictly related to the herd-seroprevalence. Considering 2.5% as the limit of detection of within-herd seropositivity prevalence, the diagnostic sensitivity showed by the proposed method was equal to 100%. A single reactivation of a whole strain vaccine in an old cow was detected inside a group of 67 lactating cows, showing the field applicability of the method.
authors.affiliation: Department of Veterinary Science, University of Torino, Italy. Electronic address: elvira.muratore@unito.it.
authors.forename: Elvira
authors.initials: E
authors.lastname: Muratore
authors.affiliation: Department of Veterinary Science, University of Torino, Italy. Electronic address: luigi.bertolotti@unito.it.
authors.forename: Luigi
authors.initials: L
authors.lastname: Bertolotti
authors.affiliation: Department of Veterinary Science, University of Torino, Italy. Electronic address: chiara.nogarol@unito.it.
authors.forename: Chiara
authors.initials: C
authors.lastname: Nogarol
authors.affiliation: Istituto Zooprofilattico Sperimentale di Piemonte Liguria e Valle d'Aosta, Torino, Italy. Electronic address: claudio.caruso@izsto.it.
authors.forename: Claudio
authors.initials: C
authors.lastname: Caruso
authors.affiliation: Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro, Italy. Electronic address: llucchese@izsvenezie.it.
authors.forename: Laura
authors.initials: L
authors.lastname: Lucchese
authors.affiliation: Department of Veterinary Science, University of Torino, Italy. Electronic address: bryan.iotti@unito.it.
authors.forename: Bryan
authors.initials: B
authors.lastname: Iotti
authors.affiliation: Azienda Sanitaria Locale TO3, Torino, Italy. Electronic address: dariello@aslto3.piemonte.it.
authors.forename: Dario
authors.initials: D
authors.lastname: Ariello
authors.affiliation: Azienda Provinciale Servizi sanitari, Trento, Italy. Electronic address: angela.moresco@apss.tn.it.
authors.forename: Angela
authors.initials: A
authors.lastname: Moresco
authors.affiliation: Istituto Zooprofilattico Sperimentale di Piemonte Liguria e Valle d'Aosta, Torino, Italy. Electronic address: loretta.masoero@izsto.it.
authors.forename: Loretta
authors.initials: L
authors.lastname: Masoero
authors.affiliation: Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro, Italy. Electronic address: snardelli@izsvenezie.it.
authors.forename: Stefano
authors.initials: S
authors.lastname: Nardelli
authors.affiliation: Department of Veterinary Science, University of Torino, Italy. Electronic address: sergio.rosati@unito.it.
authors.forename: Sergio
authors.initials: S
authors.lastname: Rosati
mesh_terms: D000818:Animals; D002417:Cattle; D003612:Dairying; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods / Q000662:veterinary*; D005260:Female; D007242:Herpesvirus 1, Bovine / Q000276:immunology*; D007074:Immunoglobulin G / Q000276:immunology; D007241:Infectious Bovine Rhinotracheitis / Q000175:diagnosis* / Q000276:immunology / Q000517:prevention & control; D008892:Milk / Q000276:immunology; D012680:Sensitivity and Specificity; D014764:Viral Proteins / Q000276:immunology; D014765:Viral Vaccines / Q000276:immunology*
chemical_list: D007074:Immunoglobulin G; D014764:Viral Proteins; D014765:Viral Vaccines; C046998:bovine herpesvirus type-1 glycoproteins
keywords: Bulk milk; IBR; Marker vaccination; gE ELISA