title: Estimation of the probability of freedom from bovine virus diarrhoea virus in Norway using scenario tree modelling.
abstract: Disease caused by Bovine virus diarrhoea virus (BVDV) is notifiable in Norway. An eradication programme started in 1992. The number of herds with restrictions decreased from 2950 in 1994 to zero at the end of 2006. From 2007, the aim of the programme has been surveillance in order to document freedom from the infection. To estimate the probability of freedom from BVDV infection in the Norwegian cattle population by the end of 2011, a scenario tree model of the surveillance program during the years 2007-2011 was used. Three surveillance system components (SSCs) were included in the model: dairy, beef suckler sampled at farms (2007-2010) and beef suckler sampled at slaughterhouses (2011). The design prevalence was set to 0.2% at herd level and to 30% at within-herd level for the whole cattle population. The median probability of freedom from BVDV in Norway at the end of 2011 was 0.996; (0.995-0.997, credibility interval). The results from the scenario tree model support that the Norwegian cattle population is free from BVDV. The highest estimate of the annual sensitivity for the beef suckling SSCs originated from the surveillance at the slaughterhouses in 2011. The change to sampling at the slaughterhouse level further increased the sensitivity of the surveillance.
authors.affiliation: Norwegian Veterinary Institute, P.O. Box 750 Sentrum, NO-0106 Oslo, Norway. Electronic address: madelaine.norstrom@hotmail.com.
authors.forename: Madelaine
authors.initials: M
authors.lastname: Norström
authors.affiliation: Norwegian Veterinary Institute, P.O. Box 750 Sentrum, NO-0106 Oslo, Norway. Electronic address: malin.jonsson@vetinst.no.
authors.forename: Malin E
authors.initials: ME
authors.lastname: Jonsson
authors.affiliation: Norwegian Veterinary Institute, P.O. Box 295, NO-4303 Sandnes, Norway. Electronic address: johan.akerstedt@vetinst.no.
authors.forename: Johan
authors.initials: J
authors.lastname: Åkerstedt
authors.affiliation: Norwegian School of Veterinary Sciences, Department of Production Animal Clinical Sciences, P.O. Box 8146 Dep. , NO-0033 Oslo, Norway. Electronic address: anne.c.whist@nvh.no.
authors.forename: Anne Cathrine
authors.initials: AC
authors.lastname: Whist
authors.affiliation: Norwegian Veterinary Institute, P.O. Box 750 Sentrum, NO-0106 Oslo, Norway. Electronic address: anja.kristoffersen@vetinst.no.
authors.forename: Anja Bråthen
authors.initials: AB
authors.lastname: Kristoffersen
authors.affiliation: Norwegian Veterinary Institute, P.O. Box 750 Sentrum, NO-0106 Oslo, Norway. Electronic address: stale.sviland@vetinst.no.
authors.forename: Ståle
authors.initials: S
authors.lastname: Sviland
authors.affiliation: Norwegian Veterinary Institute, P.O. Box 750 Sentrum, NO-0106 Oslo, Norway. Electronic address: petter.hopp@vetinst.no.
authors.forename: Petter
authors.initials: P
authors.lastname: Hopp
authors.affiliation: National Veterinary Institute, Department for Disease Control and Epidemiology, Zoonosis Center, SE-751 89 Uppsala, Sweden. Electronic address: helene.wahlstrom@sva.se.
authors.forename: Helene
authors.initials: H
authors.lastname: Wahlström
mesh_terms: D000822:Animal Husbandry; D000818:Animals; D001912:Bovine Virus Diarrhea-Mucosal Disease / Q000453:epidemiology* / Q000821:virology; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology* / Q000821:virology; D001908:Diarrhea Viruses, Bovine Viral / Q000502:physiology*; D005260:Female; D008297:Male; D008962:Models, Theoretical; D009664:Norway / Q000453:epidemiology; D015995:Prevalence; D011338:Probability Theory
keywords: Bovine virus diarrhoea; Cattle; Freedom from disease; Norway; Scenario tree model; Surveillance