title: Efficacy of Suvaxyn CSF Marker (CP7_E2alf) in the presence of pre-existing antibodies against Bovine viral diarrhea virus type 1.
abstract: Classical swine fever (CSF) is still one of the most important viral diseases of pigs worldwide and outbreaks are notifiable to the OIE. The different control options also include (emergency) vaccination, preferably with a vaccine that allows differentiation of infected from vaccinated animals (DIVA principle). Recently, the chimeric pestivirus "CP7_E2alf" (Suvaxyn® CSF Marker, Zoetis) was licensed as live attenuated marker vaccine by the European Medicines Agency (EMA). In the context of risk assessments for an emergency vaccination scenario, the question has been raised whether pre-existing anti-pestivirus antibodies, especially against the vaccine backbone Bovine viral diarrhea virus type 1 (BVDV-1), would interfere with "CP7_E2alf" vaccination and the accompanying DIVA diagnostics. To answer this question, a vaccination-challenge-trial was conducted with Suvaxyn® CSF Marker and the "gold-standard" of live-modified CSF vaccines C-strain (RIEMSER® Schweinepestvakzine) as comparator. Pre-existing antibodies against BVDV-1 were provoked in a subset of animals through intramuscular inoculation of a recent field isolate from Germany (two injections with an interval of 2weeks). Twenty-seven days after the first injection, intramuscular vaccination of pre-exposed and naïve animals with either "CP7_E2alf" or C-strain "Riems" was performed. Seven days later, all vaccinated animals and two additional controls were oro-nasally challenged with highly virulent CSF virus (CSFV) strain Koslov. It was demonstrated that pre-existing BVDV-1 antibodies do not impact on the efficacy of live attenuated vaccines against CSF. Both C-strain "Riems" and marker vaccine "CP7_E2alf" were able to confer full protection against highly virulent challenge seven days after vaccination. However, slight interference was seen with serological DIVA diagnostics accompanying the vaccination with CP7_E2alf. Amended sample preparation and combination of test systems was able to resolve most cases of false positive reactions. However, in such a co-infection scenario, optimization and embedding in a well-defined surveillance strategy is clearly needed.
authors: Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Südufer 10, 17493 Greifswald-Insel Riems, Germany.
authors: Carolin
authors: C
authors: Dräger
authors: Department of Experimental Animal Facilities and Biorisk Management, Friedrich-Loeffler-Institut, Suedufer 10, 17493 Greifswald-Insel Riems, Germany.
authors: Charlotte
authors: C
authors: Schröder
authors: Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Südufer 10, 17493 Greifswald-Insel Riems, Germany.
authors: Patricia
authors: P
authors: König
authors: Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Südufer 10, 17493 Greifswald-Insel Riems, Germany.
authors: Birthe
authors: B
authors: Tegtmeyer
authors: Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Südufer 10, 17493 Greifswald-Insel Riems, Germany.
authors: Martin
authors: M
authors: Beer
authors: Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Südufer 10, 17493 Greifswald-Insel Riems, Germany. Electronic address: sandra.blome@fli.bund.de.
authors: Sandra
authors: S
authors: Blome
mesh_terms: D000818:Animals; D057134:Antibodies, Neutralizing / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood / Q000276:immunology*; D001428:Bacterial Vaccines / Q000276:immunology*; D006691:Classical Swine Fever / Q000517:prevention & control*; D060085:Coinfection / Q000276:immunology; D030241:Diarrhea Virus 1, Bovine Viral; D034421:Sus scrofa; D013552:Swine; D014613:Vaccines, Attenuated / Q000276:immunology
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D001428:Bacterial Vaccines; C584845:Suvaxyn M.hyo; D014613:Vaccines, Attenuated
keywords: BVDV antibodies; CP7_E2alf; Classical swine fever; DIVA diagnostics; Efficacy; Marker vaccine