Threat of infectious hog disease will only increase, says vet

Porcine epidemic diarrhea virus Cooler temperatures will give the disease a better chance at surviving trips across the border on trucks

As he walked out of a southwestern Ontario hog barn, Dr. Greg Wideman was happy he hadn’t seen any signs of porcine epidemic diarrhea virus.

It wasn’t a surprise: no cases of the super-infectious disease have appeared in Canada, even though proven cases in the United States are approaching 400 and it has spread across all significant hog production zones in the U.S.

However, it didn’t help Wideman relax about the disease because recent research and the season make him worry about the coming months.

“About one in five trucks that goes to a U.S. hog slaughter facility comes out of it with the disease on it,” said Wideman, president of the Canadian Association of Swine Veterinarians.

“It’s still pretty early days with this disease, so we still have a lot to learn.”

Research conducted by swine veterinary specialist James Lowe of the University of Illinois found that 17 percent of the almost 700 trailers sampled at seven Midwest slaughter plants in mid-June carried the disease, and 11 percent of uninfected trailers that arrived left carrying the virus.

Lowe said this demonstrates that trucking can be a vector for the disease and that what arrives on the truck and goes into the plant can spread to clean trucks.

Hog truck traffic between Canada and the U.S. is heavy. There used to be much more before country-of-origin labelling slowed trade, but millions of Canadian pigs still travel to American slaughter plants and feeder barns and then return to Canadian farms.

The disease keeps appearing in new places in the U.S., with Tennessee and Texas being newly added to the list.

Wideman said the challenge of keeping PEDV out of Canada will become tougher after the summer, when cooler temperatures give the disease a better chance of surviving the trip from the U.S. to Canada on an infected truck. Trucks are easier to clean and dry in the summer, and many diseases are more resilient in cold temperatures.

Canadian veterinarians are looking for the disease, and all swine practitioners know about it. The Canadian Swine Health Board provides information and links about PEDV, and the Canadian Swine Intelligence Network is helping connect people within the industry.

No place that has been infected has yet been able to eradicate the disease. North American veterinarians and hog experts had hoped it could be eliminated entirely, but its spread across all of the Midwest to North Carolina and into the South make it unlikely.

Experts say the disease also appears to be tougher than originally thought, surviving transportation better than expected.

Europe has been unable to eradicate the disease, and it is believed to be endemic in China.

PEDV can be brutally lethal for piglets, killing up to 100 percent of infected animals. However, in older pigs it is just a temporary growth-halting affliction.

Pigs are believed to develop the disease after consuming feces-tainted materials.

Wideman said rigorous biosecurity at the barn and ensuring trucks are clean before entering the yard are essential steps for controlling the disease.