Hog producers in Minnesota and elsewhere are taking aggressive steps against an epidemic pig virus that devastated herds last winter.
Two new experimental vaccines are available for sows, and pig farmers are ratcheting up biosecurity strategies, including high-tech truck washes that “bake” vehicles at high temperatures to kill the virus and prevent its spread.
“The next six to eight weeks should be pretty telling” as far as how the virus spreads this year, said Justin Roelofs, swine specialist and financial services officer for AgStar Financial.
The highly contagious disease, known as porcine epidemic diarrhea virus (PEDv), killed about 7.5 million newborn pigs in more than 30 states last year, and infected an estimated 50 to 60 percent of swine farms. It kills baby pigs soon after birth, and seems to thrive and persist in colder weather.
The virus almost certainly originated in China, and no one knows how it entered the United States in May 2013. It is infectious only to swine, and is not a food safety concern or a threat to other livestock.
But the stakes are high in Minnesota, the nation’s second-largest pork producer after Iowa, and home to two large pork processing plants: Hormel in Austin and JBS in Worthington.
“Pork is one of the more highly consumed proteins out there,” said Steve Tousignant, associate veterinarian and infectious disease specialist for the St. Peter-based Swine Vet Center. The speed and virulence of last winter’s outbreaks startled everyone, he said, and farmers, university researchers, veterinarians and government regulators have been working together with unprecedented urgency to get the disease under control.
Reports of new infections slowed sharply during the summer, Tousignant said, perhaps in part because the virus does not seem to survive as long in warm weather.
“Everybody is certainly very nervous about what this is going to look like even within the next few weeks and whether we’re going to start seeing an increase in the number of new cases again,” he said. “Everybody’s really, really got their attention tuned into that right now.”
Jose Vera, who manages 6,000 sows on two farms in southwestern Minnesota’s Lyon County, certainly hopes that this winter will not be a repeat of last year. His herds became infected in late January and early March, he said, and the virus has killed more than 50,000 baby pigs.
“The pig mortality is sky high,” Vera said. “You have to superclean, supersanitize, and we set the temperature at 100 degrees for 24 hours. But even doing all that, the pigs still get sick.”
The rate of losses dropped during the summer, Vera said, and he has been testing new vaccines released in the past few months.
Federal officials granted conditional approval for two vaccines that are now being used and evaluated. A third vaccine, by MJ Biologics of Mankato, has been field-tested under supervision of licensed vets at Vera’s operations and elsewhere, and has shown “positive results,” said MJ Biologics chief executive Bill Marks.
“We’re trying to get it conditionally licensed as soon as possible,” Marks said. “We hope it can be available fairly rapidly.”
The vaccines do not destroy the virus and are not a “silver bullet,” he said. They function mainly by giving sows and their piglets immunity to PEDv.
It is the newborns that are mostly vulnerable, and the virus causes them to “scour,” or dehydrate and die within a day or two.
The virus has less effect on older pigs and hogs that may get sick for a few days and stop gaining weight, but usually recover.
Dave Preisler, executive director of the Minnesota Pork Producers Association, said it’s too early to tell how effective the vaccines will be. “None of them would prevent it upfront,” he said. “They would be best used in herds that have already been exposed to the virus.”
Preisler said that the vaccines are a welcome addition, but the industry is also pushing hard to promote stronger biosecurity to stop the virus from spreading to uninfected farms. Because PEDv spreads through manure, producers are adopting stricter controls on anyone who visits a farm, including those who deliver supplies and workers who may inadvertently spread the virus on boots or clothing as they come and go.
Some producers have also built high-tech truck washes for vehicles or equipment used to haul pigs, feed and other products. The washes go beyond the traditional spray-and-suds model and are designed to also disinfect the vehicles and bake them at 160 degrees F. for 10 minutes to kill viruses.
Others, especially those who manage sow operations, are installing more sophisticated air filtering systems, Preisler said.
“It’s the same type of filters that are used in a surgery suite in a hospital, or a clean room in a high-tech manufacturing company where they will actually capture any viruses and bacteria in that filter before the air actually enters into the barn,” he said.
Producers have instituted biosecurity measures in the past, Preisler said, but the urgency has ramped up because PEDv “really got people’s attention and pushed it over the edge.”
Roelofs said the immense number of pigs killed in last year’s outbreak meant fewer hogs and higher prices in supermarkets this summer for bacon, ham and other pork products. Prices have remained strong for several reasons, he said, including demand for exports, but marketers are also watching closely to see what happens with the virus and pig production rates this fall and winter.
“Producers want to save every pig, so they hate this virus — or any virus, for that matter,” Roelofs said. “But at least on the backside you can still make money if you do have to deal with it.”