Since the introduction of the porcine epidemic diarrhea virus (PEDV) in 2013 to the US swine industry, this disease has established itself and remains in the swine population, noted Paul Yeske, Swine Vet Center, during the 2023 Leman Swine Conference.

The success rate for elimination at the herd level is high, with many successes in the industry. The principle of herd closure and homogenize followed by strict cleanup and good hygiene has worked well, he said.

There is a definite seasonal pattern to the disease with activity being the highest in winter months, Yeske said. Every year there is a limited number of sow farms becoming positive with PEDV. Usually, less than 9% of the sow herd is positive, he added.

Once PEDV starts circulating it does not take long for it to move, Yeske emphasized. One key factor is transportation, which was demonstrated early in the outbreak in 2013, as the packing plants were contaminated quickly, and trucks had a higher likelihood of becoming positive after being at the plants. This in turn results in market channels, including cull sows, becoming contaminated quickly and can potentially be sources of infection, he added.

With herd closures, the elimination time for PEDV has been reduced to as low as 90 days in some cases, depending on the specifics of the herd and diagnostic testing. Timing the herd elimination process to be completed by the middle of summer means the virus load will be smaller, which allows for doing a better job of cleanup, he noted.

An elimination program for a farm requires: cooperation between staff, strong communication and good surveillance to be successful, Yeske said.

There is still a significant impact on the sow herds that are affected, and there are added costs associated with cleanup, stabilizing the herd and going on to elimination. Herds that have chosen to live with the disease still have significant costs with ongoing monitoring and the effect on gilts that are exposed in new outbreaks that occur in the system because there is still active virus present, he said.

“My bias has always been to eliminate any disease that we can as an industry. I believe that long term this only makes the industry more sustainable. Although there are more severe economic diseases that impact herds every year, there is still a significant impact on the sow herds that are affected by PEDV,” Yeske concluded.