The Ontario Pork Industry Council is alerting farmers to be extra cautious about where their trucker has been, now that many are hauling hogs from Quebec to the United States.
Olymel, the dominant Quebec packer, is on strike.
Those returning trailers could infect unloading chutes at Ontario packing plants.
As a result, the council says Ontario farmers should insist that their truckers have thoroughly cleaned, washed and disinfected their trailers before coming to their barns.
Porcine Epidemic Diarrhea virus is widespread in the United States, so any Canadian hog shipments to American packers could become infected and bring the highly-contagious virus back to Canada.
The virus is particularly resilient in the kind of cold weather being experienced this week.