title: Probability of introducing porcine epidemic diarrhea virus into Danish pig herds by imported spray-dried porcine plasma.
abstract: BACKGROUND
  Porcine epidemic diarrhea virus (PEDV) has never been reported in Denmark, but it has been found in Europe, Asia and North America. Ultimately, PEDV has been associated with devastating outbreaks in pig farms. We developed a stochastic simulation model to carry out a quantitative risk assessment and to estimate the annual probability (PPlasma) of introducing PEDV into the Danish pig population, by imported spray-dried porcine plasma (SDPP). The model was based on information from literature and Danish feed companies. Moreover testing the batch of raw blood (before the spray-drying) was considered as potential risk mitigation measure in the future.
  
  
  RESULTS
  The medianPPlasmawas 0.2 % (90 % P.I.: 0.003 %; 2.6 %). Hence, the annual probability of introducing PEDV into the Danish pig population by imported SDPP appeared very low, and on average at least one introduction each 500 years - corresponding to 1/0.002 - could be expected. However, if PEDV survived the spray-drying process and storage was insufficient to completely remove the remaining viable virus (e.g. due to storage at low environmental temperatures during a short time period) thePPlasmawas 4.7 % (0.06 %; 57.4 %). In that case, on average, at least one PEDV introduction each 21 years could be expected. This probability could be reduced to 0.3 % (0.004 %; 6.0 %) if the raw batch of blood could be tested before drying (corresponding to at least one introduction each 333 years on average).
  
  
  CONCLUSIONS
  This study provides preliminary and important information on the probability of introducing PEDV into the Danish pig population by use of SDPP. Currently PED is not a notifiable disease in the EU and uncertainty was present in our estimates due to possible underreporting in EU Member States, from which SDPP is imported into Denmark. In the future, PED might become a notifiable disease, and in such a case, new knowledge could become available on its epidemiology. Moreover, SDPP could be imported more safely if: producers find a way to substantiate freedom from disease (at least) in herds delivering blood for SDPP, the batch of blood tests negative for PEDV and conditions for processing/storage required by the international laws are respected.
authors.affiliation: Risk Analysis Group, Department of Food Safety and Veterinary Issues, Danish Agriculture & Food Council, Axeltorv 3, DK-1609 Copenhagen V, Denmark.|Section of Epidemiology, Technical University of Denmark, National Veterinary Institute, Bülowsvej 27, DK-1870 Frederiksberg C, Denmark.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Foddai
authors.affiliation: Risk Analysis Group, Department of Food Safety and Veterinary Issues, Danish Agriculture & Food Council, Axeltorv 3, DK-1609 Copenhagen V, Denmark.
authors.forename: Lisbeth Harm
authors.initials: LH
authors.lastname: Nielsen
authors.affiliation: Risk Analysis Group, Department of Food Safety and Veterinary Issues, Danish Agriculture & Food Council, Axeltorv 3, DK-1609 Copenhagen V, Denmark.
authors.forename: Vibeke
authors.initials: V
authors.lastname: Møgelmose
authors.affiliation: Risk Analysis Group, Department of Food Safety and Veterinary Issues, Danish Agriculture & Food Council, Axeltorv 3, DK-1609 Copenhagen V, Denmark.
authors.forename: Lis
authors.initials: L
authors.lastname: Alban
keywords: Import; Risk assessment; Spray-dried porcine plasma; Stochastic simulation model