An epidemiological investigation of the early phase of the porcine epidemic diarrhea (PED) outbreak in Canadian swine herds in 2011

Project 14-007 - Terri O’Sullivan, University of Guelph

Project 14-007
Researcher: Dr. Terri O’Sullivan, Population Medicine, University of Guelph
Graduate student: Amanda Perri, PhD, Population Medicine, University of Guelph

Project start: May 2015  Project finish: May 2019

FINAL REPORT
RESEARCH SNAPSHOT
ABSTRACT in Preventive Veterinary Medicine

In January 2014, the first case of porcine epidemic diarrhea virus (PEDV) was reported in an Ontario swine herd; which was soon followed by a series of other cases.  Feed from a single feed company was implicated as a source of the virus during the early phase of the outbreak.  The overall objective of this study was to conduct an evaluation of the role of feed and other possible factors in the early phase of the PED outbreak in Ontario swine herds that occurred in 2014.  
The time period studied was from Jan 22nd to Mar 1st, 2014. A questionnaire was administered to herd managers of participating swine herds with questions focused on herd demographics, biosecurity protocols, live animal movements onto and off sites, deadstock movements, feed and people movements during the period-of-interest.  Three hypotheses were evaluated: 1) whether farms associated with a feed supplier, semen supplier and/or animal transportation company networks contained a higher proportion of case (PED) herds, 2) whether the proportion of case herds differed from controls, and 3) whether external herd biosecurity, was different between case and control herds.  
 
Statistical analyses demonstrated that PEDV occurrence was 38.1 (95% CI: 2.7–531.3) times greater for herds receiving feed from feed companies that provided contaminated feed (P=0.007) than herds that did not. The studies also supported that the neither the frequency of animal or human movements, nor the transport company or semen supplier was associated with the odds of contracting PEDV in the period-of-interest (the early phase of PEDV outbreak in Ontario).  
 
Conclusions:  
 
• Feed containing contaminated Spray Dried Plasma protein was a risk factor for PED during the initial phase of the outbreak 
• A specific feed supplier (supplying contaminated feed ingredient) was identified as a risk for PEDV transmission 
• Non-feed service suppliers did not have an impact on PEDV spread even though connections among swine herds and service suppliers were identified during the initial PED outbreak 
• Animal and human movement on and off of farms did not have an impact on PEDV spread during the initial phase 

Additional Resources:

• Page 65 of Better Pork June 2018 issue
• Perri, A.M., Poljak, Z., Dewey, C., Harding, J.C.S., O’Sullivan, T.L. 2018. An epidemiological investigation of the early phase of the porcine epidemic diarrhea (PED) outbreak in Canadian swine herds in 2014: A case-control study. Prev. Vet. Med. 150(1):101-109. 
• Perri, A.M., Poljak, Z., Dewey, C., Harding, J.C.S., O’Sullivan, T.L. 2019. Network analyses using case-control data to describe and characterize the initial 2014 incursion of porcine epidemic diarrhea (PED) in Canadian swine herds. Prev. Vet. Med. 162(1): 18–28.