Building Immunity to PEDv Is Critical

Develop a comprehensive action plan to help protect your farm

Pork producers know lower temperatures can mean a heightened risk for porcine epidemic diarrhea virus (PEDv). Fortunately, the industry is now more knowledgeable, more prepared and better equipped to help minimize the spread of PEDv this winter.  

Despite increased preparedness, variation in immunity remains within the U.S. pig herd. Some farms have exposed replacement gilts to PEDv to help build immunity, while others have introduced naïve gilts and sows into their farms. Given this challenge, Matt Ackerman, DVM, Swine Veterinary Services, recommends producers start collecting oral fluid samples from gilts for testing prior to introducing them into the sow herd. This action will help prevent producers from inadvertently introducing the virus to a farm.

“Diagnostic labs have developed tests to quickly confirm what we are facing with PEDv,” Dr. Ackerman said. “Previous exposure to PEDv does not ensure your animals have immunity.”

Ackerman was among the first veterinarians in the U.S. to diagnose PEDv in 2013, and he was one of the first to experience a rebreak with a client in 2014. Noting the rebreak took twice as long to eliminate, he encourages producers and veterinarians to be prepared and consider effective ways to manage immunity, such as oral live viral exposure and vaccination.

Oral live viral exposure

“If a farm is exposed, efforts need to focus on homogenizing that sow and gilt population with oral live virus exposure. The process of administering oral live viral exposure to acclimating gilts should continue for as long as virus shedding is occurring in the farrowing house, Dr. Ackerman recommends.
Then, producers need to look at a vaccination program to make sure they can stabilize that virus and knock down the amount of shedding that is going on at the sow farm,” he said.


To boost immunity, vaccination is recommended for gilts after oral live virus exposure and for sows and gilts prior to farrowing. When vaccinating, be sure to follow all label directions for proper use, dosing, handling and timing to ensure all animals are vaccinated consistently.

“By not vaccinating, there’s a concern for continued shedding or various levels of immunity in the sow population,” Dr. Ackerman said. “We need to boost immunity to reduce the amount of maternal antibody differences in piglets to help maximize protection in the farrowing house, which is most vulnerable.”

After vaccination, it’s crucial for piglets to get adequate colostrum.

“The sow can have adequate immunity, but if she doesn’t pass it on in colostrum, you aren’t going to get the effect you need for added immunity,” said Rick Swalla, senior veterinarian, Pork Technical Services, Zoetis. 

Vaccination is a tool to work in conjunction with good biosecurity and sanitation. In addition to building immunity, work with your farm veterinarian to design and update biosecurity practices and audit existing protocols.

“Your farm veterinarian is going to do the best job of creating comprehensive protocols that will work best for your farm,” Dr. Swalla said. “That’s key — this is part of many tools to help prevent PEDv as well as expedite the process of restoring farms’ health.”

For more information on staying prepared for PEDv this winter, contact your local Zoetis representative, visit or subscribe to Pork Perspectives from Zoetis.

About Zoetis

Zoetis (zō-EH-tis) is the leading animal health company, dedicated to supporting its customers and their businesses. Building on more than 60 years of experience in animal health, Zoetis discovers, develops, manufactures and markets veterinary vaccines and medicines, complemented by diagnostic products and genetic tests and supported by a range of services. In 2014, the company generated annual revenue of $4.8 billion. With approximately 10,000 employees worldwide at the beginning of 2015, Zoetis serves veterinarians, livestock producers and people who raise and care for farm and companion animals with sales of its products in 120 countries. For more information, visit

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