Date Full Report Received02/06/2015
Date Abstract Report Received02/06/2015
InvestigationInstitution: Carthage Innovative Swine Solutions, LLC
Primary Investigator: Laura Greiner
Funded ByNational Pork Board
Twenty-four feed mills from various regions (Eastern, Midwest, Western, and Northern Midwest) in the US were evaluated in this study to assess the risk of different areas within a mill to test positive for either porcine epidemic diarrhea virus (PEDv) or swine delta coronavirus (PDCov). Samples were collected at each feed mill for multiple days. Sample areas included: both foot pedals of feed delivery truck, bulk ingredient unloading pit, inside mixer/pellet cooler, mill office floor, inside feed compartment on feed truck, and incoming bagged ingredient truck (inside of truck near site of off-loading). Samples were collected using a technique similar to the Swiffer® technique described by Dee et al. using gauze instead of Swiffers®. Samples were tested for the presence of PEDv and PDCov. Data were analyzed as odds-on-ratios and risk assessments for each area within the mill being tested. Raw percentages demonstrated that no samples tested positive for PEDv. However, 5% of the truck foot pedals and 1% of the bulk ingredient pit tested suspect for PEDv. Porcine delta coronavirus particles were found on 3.4% of the foot pedals of the trucks and 2.2% of the office floors tested suspect. Mills feeding herds that were either PEDv or PDCov positive had a greater probability of having either a suspect or positive test. In addition, for each day a negative test against PEDv or PDCov on the foot pedal was found the chance of a PEDv positive/suspect result declined from 73.6% to 67.7% and PDCov declined from 28% to 17.7%.
Although this study did not determine if positive/suspect samples were in fact capable of producing an infection in an animal, the presence of the virus indicates a risk factor. One mill that was not servicing PDCov positive pigs did have a suspect PDCov PCR, which indicates that herd health status is not the only potential cause for a positive/suspect finding. Furthermore, based on these data, the presence of either PEDv or PDCov particles demonstrates that feed mills and farm owners should review their current biosecurity practices to minimize the potential risk of transferring the virus.