Minn. veterinarians discuss PEDv

WORTHINGTON, Minn. -- An epidemic sweeping through the U.S. swine industry, causing 100 percent mortality in suckling pigs and minimal death loss in feeder pigs and sow herds, was the topic of conversation Thursday afternoon at the 10th annual Worthington (Minn.) Bio Conference.

Keith Wilson, director of the swine business unit at Newport Laboratories and a veterinarian, referred to the Porcine Epidemic Diarrhea virus (PEDv) as a viral storm.

"It really did roll through the country -- it just kind of sprung up in many different areas," Wilson told approximately 30 session attendees on the first day of the two-day bioscience conference.

PEDv was first discovered in the U.S. on April 15, 2013, on an Ohio farm. Within a week, a case had shown up on a hog farm in Indiana. Within two weeks, it had spread to farms in Iowa.

"We know it came from China, we don't know how," said Steve Dudley, a veterinarian and CEO of the Veterinary Medical Center in Worthington.

Wilson said the virus discovered in China in 2012 is 99.4 percent similar to PEDv.

As of Thursday, the virus had been reported in swine operations in 26 states across the U.S., with more than 830 cases in Minnesota alone.

"It has been a real challenge -- a real frustration to our industry," Dudley told attendees. "(It is) a real economic impact to our industry."

Dudley said with pigs valued at $80 per head, and a running average of 1,688 pigs lost per 1,000 sows, the impact to producers can be as high as $135,000 for each 1,000-sow farm. A recent Rabobank estimate is that 12.5 to 15 million pigs will die -- that's 6 percent to 7 percent of the nation's hog production.

The virus has led to the biggest drop in pork production in 30 years. As the supply of pigs going to market drops, it will likely mean added costs for consumers.

Dudley said the virus is deadly for pigs less than 15 pounds. The newborns don't have the antibodies to fight off the symptoms of the virus -- vomiting and watery diarrhea that lead to severe dehydration.

"They have such a severe diarrhea they can't function," he explained. "They're cold, wet and they tend to lay on the sow. In the old days, anytime the pigs were laying on the sow, it was TGE (Transmissible Gastroenteritis). That's not true anymore -- now it's PED."

TGE and PED are in the same family of coronavirus, and there is no cross-protection between strains, Dudley said. The primary difference is that TGE has respiratory impacts and PED does not.

One of the methods now being used to build up immunity in baby pigs is to take a natural approach. Dudley said intestines can be taken from pigs that have died from PEDv -- or the manure from scouring piglets -- and fed back to the rest of the animals on the farm.

"Everyone has to develop a high immunity for this not to recur," Dudley said. "It's natural vaccination. Although it's not very pleasant to think about, it's very effective."

One of the issues with the natural approach is time. It takes two to three weeks for a sow to develop immunity after being naturally infected with the virus. In addition, the sow has to endure clinical signs of PEDv for three to five days.

Once the sow has immunity, however, she passes that to her nursing piglets through her colostrum milk. Dudley said the antibodies in the colostrum have been shown to protect piglets for up to six weeks. By then, the intestines of the piglets have matured enough to be able to fight off the virus.

Research done thus far has shown older grower and feeder pigs have just a 1 percent to 3 percent mortality from PEDv, while death loss in sows is minimal. Both age groups still suffer from vomiting and diarrhea as the virus works through their system.

Local response

Newport Laboratories, which manufactures autogenous vaccines for the swine industry in its Worthington facilities, has been working -- like many other companies -- to develop a response to the virus.

"The success story is the amount of diagnostic testing and laboratory work that was done," Dudley said.

Wilson said on May 15, 2013, Newport Labs received its first pigs afflicted with the PED virus. At the time, the virus was still unidentified as such.

Today, Newport continues to work on diagnostics and vaccine development.

"We are licensed to produce a vaccine from pathogens isolated from specific farms," Wilson said, adding that Newport has the ability to provide a quick response to an emerging disease.

"This is a very difficult virus to grow," he explained. "We have to creative ways to make this virus grow."

Meanwhile, Wilson said the fact that PEDv showed up in the U.S. highlights the need for better security to keep contagious diseases from impacting livestock herds.

"What's to keep Foot and Mouth Disease from coming in?" Wilson questioned. "The methods in place right now aren't working. You need to shore up the borders. This could be a big deal in years to come."

Foot and Mouth Disease is considered a foreign animal disease (FAD), which requires countries to report its presence and immediately stop exports. If an FAD were to break out in the U.S., it could be devastating to the livestock industry. In the pork sector alone, roughly 30 percent of all pork produced in the U.S. is exported, Wilson said. PEDv is not considered a FAD.

However, with the quick spread of PEDv and its believed origins in China, Wilson said it has proved "that we're all vulnerable."

"We need to be able to respond quickly with a vaccine," he said. "Diseases change and adapt, and science and new technology will lead the way to solutions."

Newport Labs hopes to have a vaccine for PEDv available within 30 days through its process of growing the virus. But it could be a year or two -- or as many as five years -- before a product would be available on a mass scale.

"It takes a long time to get a vaccine to market," Dudley said. "That's why, with foreign animal disease issues, we have to be prepared. To wait for a commercial vaccine is going to be a real challenge to our industry."

That challenge has certainly been brought to light with PEDv.

"Although we've been able to diagnose it quickly, the failure is even though we identified it quite early, we were not able to stop it," Dudley said.

At this point, the best thing producers can do is keep the virus from spreading or reaching their farm.

Dudley's take-home message to producers is to reevaluate their biosecurity, practice rapid recognition and pursue diagnostics.

"It's important to stay up on hygiene and cleanliness," he said. "If an employee breaks biosecurity one time, it can be (disastrous)."

"The PED virus does not pose any food safety concerns and there is no public health issue," Wilson said.