Ready or not, winter is here. And with winter’s colder temperatures comes the threat of Porcine Epidemic Diarrhea virus’s (PEDv) return. Even though pork producers today are more prepared for the disease than in previous years, the dissipating natural immunity puts more farms at a higher risk of PEDv returning this winter.

Dr. Paul Sundberg, executive director of the Swine Health Information Center, explained to Farmscape that no one really knows what the winter is going to hold.

“We do know from our research that we can expect that the immunity from natural infection is not long-lasting, so a sow herd or even a finisher or any farm that's gone through an infection recently very well may have susceptible animals that show up as early as 4 to 6 months after a natural infection,” he said.

According to the USDA, there were 24 premises with confirmed positive tests for PEDv as of Dec. 2. Considering PEDv remains active, Sundberg expects that the nation has “an increased number of susceptible animal out in the countryside right now.”

Steve Meyer and Len Steiner agree.

“Producers and their veterinarians know that [immunity levels] will be lower due to both the natural tendency for antibody levels to decline after exposure to a virus and the fact that a good number of the sows that went through the large number of 2013-2014 breaks have now been culled,” Meyer and Steiner pointed in a recent Daily Livestock Report update. 

Though many systems continue to expose replacement gilts to PEDv prior to entering the sow herd, it likely won’t be enough to duplicate the PEDv-combatting abilities seen in the national sow herd after the first winter of PEDv.

Read, “Winter is coming – what about PEDv?”

In anticipation of a possible increase in confirmed PEDv cases, there is still plenty to do for producers and veterinarians alike.

“What we've been trying to do is communicate to producers and veterinarians the need to be vigilant,” Sundberg stressed. “The need to keep those biosecurity practices in place because we can't assume that PED went through the wave of the countryside and is going to be gone.”

Click here for more from Sundberg’s interview with Farmscape