GREENSBURG, Ind. — Uncertainty about a pig’s immunity to porcine epidemic diarrhea virus continues to rise as farms, including an operation in Indiana, experience second outbreaks of the disease.

It was determined the Indiana farm had been re-infected at the end of March when there were deaths of baby piglets.

The farm first had an outbreak of the virus in May 2013, had it cleaned up by September 2013 and had not had any clinical signs of the virus again until March 2014, said Matt Ackerman, veterinarian with Swine Veterinarian Services.

Facts surrounding immunity from the virus still are uncertain.

Originally, veterinarians hoped immunity would last two to three years because pigs previously had a longer-lasting response to Transmissible Gastroenteritis, a disease caused by a coronavirus similar to the virus that causes PEDV, Ackerman said.

“No one thought there would be lifelong immunity, but we certainly hoped there would be two to three years,” he said. “Now, instead of farms breaking once every three years, there could be losses every six months.”

A challenge for producers is that pigs, when born, aren’t protected from the virus.

Milder Outbreak

The second outbreak has differed from the first outbreak of the virus, Ackerman said. The first time around, the Indiana operation lost 3.6 weeks of pigs over eight weeks then went back to regular production.

The second outbreak has came in lighter, but lasted longer, Ackerman said. The operation is experiencing week 10 and has lost about three works worth of pigs.

To combat the virus, producers can do three things, Ackerman said. Producers should consider vaccination, implement biosecurity precautions and, once the virus is identified, the area needs to be sanitized with bleach or some other disinfectant or powder that kills the virus.

Tom Burkgren, executive director of American Association of Swine Veterinarians, said they have not been able to track the number operations experiencing second outbreaks.

At this point, most of the second outbreaks are anecdotal information heard through the swine vine, Burkgren said.

The reason for the recurrence of the virus is unclear because some farms clean up and don’t have recurrence and others clean up, get it back to great production and, like the Indiana farm, come out with the same strain of virus, Burkgren said.

“It’s a tough virus, and one of the problems is we don’t know everything we need to know about immunity,” he said.

As far as combating the virus, Burkgren agreed cleaning up, increasing biosecurity and considering feed risk factors are some answers.

This specific Indiana operation having litters be infected a second time is concerning because it is a well-run herd with an excellent veterinarian, Burkgren said.

“The virus has surprised us in a number of ways. It’s an area we need more knowledge,” he said.

The upcoming summer months should help with slowing down the virus.

Battle Plan

Producers should take advantage of the warmer weather and increase cleanup efforts — washing, disinfecting and drying everything that could transmit the virus back on the farm, Burkgren said.

Although the virus still is a major challenge for producers, it is not a human health concern. Pork remains completely safe to eat, and it poses no risk to other animals, people or food safety.

Ackerman said he appreciated the work being done by the U.S. Department of Agriculture, the AASV, state animal health officials, the National Pork Producers Council and the National Pork Board.

The organizations are continuing to collaborate together to fund research and find the answers needed to combat the virus.

“We’re doing all we can to eliminate the virus and will continue to do so,” Ackerman said.