Evaluation of the likelihood of detection of porcine epidemic diarrhea virus or porcine delta coronavirus ribonucleic acid in areas within feed mills

Abstract

Objective: To compare areas within feed mills to determine the likelihood of presence of either porcine epidemic diarrhea virus (PEDV) or porcine delta coronavirus (PDCoV). Materials and methods: Twenty-four feed mills from various regions in the United States were evaluated. Swab samples (foot pedals of feed delivery trucks, bulk ingredient unloading pits, inside the mixer or pellet coolers, mill office floors, inside feed compartments on feed trucks and incoming bagged-ingredient trucks) were collected daily at each feed mill for up to 5 days. The samples were submitted for polymerase chain reaction testing for PEDV and PDCoV. Results: Of the feed mills tested, 75% were supplying feed to known PEDV-positive herds, and 21% were supplying feed to known PDCoV-positive herds. No samples at any mill tested positive for PEDV ribonucleic acid (RNA), although 5% of the truck foot pedals and 1% of the bulk-ingredient pits tested suspect. Porcine delta coronavirus RNA was found on 3.4% of the foot pedals of the trucks, and 2.2% of the office floors tested suspect. Implications: Porcine delta coronavirus RNA can be detected at different locations around feed mills. Feed mill biosecurity protocols need to be evaluated and maintained to minimize the probability of PEDV and PDCoV RNA presence.