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Porcine Epidemic Diarrhea Virus (PEDV) background and current Situation in the USA

Porcine Epidemic Diarrhea Virus (PEDV) background and current Situation in the USA. Tanja Opriessnig The Roslin Institute, University of Edinburgh, UK Veterinary Diagnostic and Production Animal Medicine Iowa State University, USA. Background. Discovered in 1971 in the UK

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Porcine Epidemic Diarrhea Virus (PEDV) background and current Situation in the USA

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  1. Porcine Epidemic Diarrhea Virus (PEDV)background and current Situation in the USA TanjaOpriessnig The Roslin Institute, University of Edinburgh, UK Veterinary Diagnostic and Production Animal Medicine Iowa State University, USA

  2. Background • Discovered in 1971 in the UK • Acute outbreaks of diarrhea in feeder pigs and fattening pigs • Suckling pigs did not become sick • Oldham et al., 1972 • Family Coronaviridae • Enveloped, positive stranded RNA viruses • Subfamilies: Coronavirinae & Torovirinae • Important for pigs: • Genus Alphacoronavirus • PEDV, TGEV: Diarrhea • PRCV: Respiratory disease • Genus Betacoronavirus • Porcine haemaggluinationencrophalomyelitis virus (HEV): Encephalomyelitis • Genus Deltacoronavirus • Porcine deltacoronavirus (PDCV): Diarrhea (?)

  3. Background http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3397359 Spike • Structure: • Nucleocapsid (N) protein • Highly conserved: Best for testing • Spike (S) protein • Integral membrane (M) protein • Small envelope (E) protein Nucleocapsid Envelope protein E Membrane protein M

  4. PEDV Shedding • Possible contribution factors: • Age dependency • Differences in virulence between isolates? • Cross-protection between strains? • Interaction with other pathogens? • Fecal shedding: • Up to at least 28-35 + days post infection (neonatal and nursery pigs) • Large amounts • Viremia: • Short (days) • Low amounts

  5. Global Importance • Europe: • Epidemics until the • late 80ies; Reports • after 2000 are rare • Only infectious for pigs • No role in public health USA: PEDV still spreading 1971 2013 1982 1993 China: Severe epidemics in recent years

  6. USA Discovery Timeline Source: ISU-VDL 2013

  7. U.S. Pig Inventory 2007 Density Level http://www.factoryfarmmap.org/#animal:hogs;location:US;year:2007

  8. April 2013 IA OH IN Introduction of PEDV into the USA TIMELINE

  9. May 2013 MN SD MI IA PA IL OH IN CO MO OK Introduction of PEDV into the USA TIMELINE

  10. June 2013 MN SD MI NY IA PA OH IL IN CO KS MO OK NC Introduction of PEDV into the USA TIMELINE

  11. July 2013 MN WI SD MI NY IA PA OH IL IN CO MO KS NC TN OK TX Introduction of PEDV into the USA TIMELINE

  12. October 2013 MN WI SD MI NY IA PA OH IL IN MD CO MO KS KY TN OK NC TX Introduction of PEDV into the USA TIMELINE

  13. December 2013 MN WI SD MI WY NY IA NE PA OH IL IN MD CO MO KS CA KY TN OK NC TX Introduction of PEDV into the USA TIMELINE

  14. January 2014 MN WI SD WY MI NY IA NE PA OH IL IN MD CO MO KS KY CA TN OK NC AZ SC TX Introduction of PEDV into the USA TIMELINE

  15. February 2014 ND MT MN SD WI ID WY MI NY IA NE PA OH IL IN MD CO MO KS KY CA TN OK NC SC AZ TX Introduction of PEDV into the USA TIMELINE

  16. March 2013 ND MT MN VT ID WI SD WY MI NY NE IA PA OH IL IN MD CO MO KS KY CA TN OK NC SC AZ MS TX Introduction of PEDV into the USA TIMELINE

  17. Distribution of PEDV in the U.S Source: AASV

  18. Total Number of Positive Pig Samples 15-Jun-13 to 8-May-14: 29 (30) States are affected to date Image Source: ISU-VDL 2013

  19. 2013 Genotyping Emerging PEDVs in Asia and the US Historical PEDVs in Europe and Asia Source: Huang Y et al. mBio 2013; doi 10.1128/mBio.00737-13

  20. Origin of the U.S. PEDV strains Source: Huang Y et al. mBio 2013; doi 10.1128/mBio.00737-13

  21. Evidence of 2nd PEDV Introduction2014 Whole genome sequencing Spike protein sequencing Source: Wang et al. Emerging Infectious Disease 2014; No. 5, May 2014

  22. Diagnostics • Diagnostic Specimens • Intestines (Fresh) • Feces • Oral fluids • Intestines (Fixed) • Serum Virus isolation Real-time RT-PCR Electron microscopy Sequencing Immunohistochemistry Indirect Fluorescent Antibody, ELISA

  23. Total Number of Positive Pig Samples Weekly Basis Source: AASV

  24. Cumulative Number of Positive Samples 6,421 Source: AASV

  25. PEDV Economic Impact • Approximately 5 million pigs have died in the U.S. • About 4.5% of the animals sent to processing plants last year in the U.S • Source: AgriTrends • It is estimated 12.5 million fewer pigs will be slaughtered in 2014, which will result in an overall U.S. pork production decline of 6-7% • Largest estimated decrease in 30 years • Source: Rabobank

  26. Economic Impact of PEDV • Estimated shortfall in market hogs from PEDV to North American slaughters • ((Source: Rabobank) 0% -5% -10% -15% -20% -25% Canada US Mexico Dec 13 Mar 14 Jun 14 Sep 14 Dec 14 Mar 15 Jun 15 Sep 15 Dec 15

  27. Porcine Deltacoronavirus (PDCV) PDCV • Initially discovered in Hong Kong in 2009 (Woo et al., 2012) • Described in the U.S. in 2014 • Associated with diarrhea in sows and their litters • No experimental data to date • Precise pathogenesis and role of PDCV is currently unknown

  28. Distribution of PDCV in the U.S. PDCV Source: AASV

  29. PEDV versus PDCV Cumulative US results

  30. PEDV TransmissionWhat is known so far • Rapidly spread across U.S. • Transport vehicles • PEDV negative trucks returning from abattoirs positive (Lowe et al., 2014) • Animal movement • Aerosol transmission? Source: Dr. Darin Madson

  31. PEDV TransmissionRole of Feed • Detection of PEDV RNA in feed • Confirmation of PEDV RNA in porcine plasma derived products • Relationship with PEDV outbreaks in Canada? • Recall of pelleted nursery feeds containing plasma ingredients in Ontario • CFIA (18-Feb-14); Feedstuffs (20-Feb-14) • 4-Mar-14: CFIA could not confirm live virus in feed pellets containing blood plasma • Ban of spray-dried porcine plasma products in the UK (Vet Rec, May 2014) • Centre de développement due pork du Québec Inc (CDPQ) risk analysis • Feed is medium risk for PEDV transmission • Study by Scott Dee, Pipestone Applied Research

  32. 2014 ISU Experiment Viremia only in PEDV-CONTROL group Seroconversion only in PEDV-CONTROL group Conclusion: No evidence of infectivity of the PEDV present in the investigated plasma lot

  33. Summary • PEDV is now prevalent in the majority of swine producing states in the USA • Epidemic situation Endemic situation? • Lesion learned: Constant awareness • Globalization increases the risk of pathogen introductions • Need to invest in rapid epidemiological studies to document how PEDV was introduced to the US and learn from this situation • Need much more work on advancing understanding of transmission routes • Pigs, people, trucks, fomites, feed, air, water etc… STOP PEDV

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