LANCASTER, Wis. -- Not long ago, Doug Wolf learned all he wanted to about a virus that's killed millions of pigs in the U.S.
Two weeks ago, he discovered porcine epidemic diarrhea in his herd on a farm south of Lancaster. He's working through a long process to clean up the herd.
"We don't know when or where they got it," Wolf said.
Bruce Nieman has seen the devastating effects the virus can have. He is part of a 3,000-sow, breed-to-wean operation in northwest Clayton County -- an operation hit hard by the virus last May. An estimated 6,000 to 7,000 piglets were lost.
"They died by the bucket load," he said. "It had a terrible effect on the people around it. It was so pathetic. You had no heart if it didn't bother you."
Scientists think the virus, which does not infect humans or other animals, came from China, but they don't know how it got into the country or spread to 27 states since last May.
Estimates of how many pigs have died in the past year vary, ranging from at least 2.7 million to more than 6 million. Iowa and Illinois are among the states that have been hit the hardest.
Grant County leads Wisconsin in swine production.
Wolf, along with his wife, Kris, and son Shannon, operates a 1,200-sow farrow-to-finish operation, which markets 20,000 hogs annually.
He first noticed the virus had hit the herd when his nursing pigs started scouring. They were tested immediately, and results came back positive.
"It was one of those things my son and I read and followed," Wolf said of his reaction. "There is a lot of research. I've been at a lot of meetings. It wasn't 'if,' but 'when?' It wasn't an 'Oh my God, what happened?' I was halfway expecting it."
Wolf knows the business. A member of the Wisconsin Department of Agriculture, Trade and Consumer Protection's citizen board, Wolf is a past president of the National Pork Producers Council, served on the Wisconsin Pork Association Board and has been an agricultural industries instructor at the University of Wisconsin-Platteville.
Wolf reported everyone, from ag economists to producers to packers, still is trying to get a handle on the losses.
"Some feel it isn't going to be very bad, while others, including packing plants, have decreased kills because of the hog shortages," he said.
Wolf noted that the problem is that no one knows how to stop it yet.
"The best (way) is to prevent it from getting on the farm," he said. "We couldn't stop it. Some say it will hit every farm before it's done. The good thing is, it is heat-susceptible, so it should decrease this summer."
According to Mark Storlie, an Iowa State University Extension swine field specialist, the downward trend in positive cases in Iowa over the past six weeks, combined with the seasonal warming conditions, might help reduce survival and spread of the virus.
Some operations, like Nieman's, already are rebounding.
"The biggest advantage we had, was the disease wasn't as widespread," Nieman said. "We could find replacements, but we had to cough up a lot of money."
Today, there is no evidence of the disease on the operation.
Jude Becker and Alicia Prill-Adams were lucky.
Becker operates Becker Lane Organic Meats, a free-range, 200-sow, farrow-to-finish operation near Dyersville, Iowa.
"Knock on wood, we've had no misfortunes with this disease and no issues," Becker said. "I'm thankful, and I hope it stays that way."
Prill-Adams serves as assistant farm director at UW-P's Pioneer Farm, where she is responsible for the management of the swine and beef operation.
The farm hasn't been affected. Prill-Adams said management worked with the faculty and students to compromise on maintaining the health status of the facility while also allowing for the opportunity for classes to learn through hands-on experiences.
"We farrowed more than 50 litters this winter and have an outstanding pig crop," she added.
Wolf emphasizes there is absolutely no threat to humans.
"There's no impact on the meat. It's perfectly safe," he said.
While the pork itself is not impacted, its prices already are.
"It's going to have an effect, no two ways around it," he said.
Already, prices have shot up: A pound of bacon averaged $5.46 in February, 13 percent more than a year ago, according to the U.S. Bureau of Labor Statistics.
Experts predict that pork prices likely will be 10 percent higher overall this summer than a year ago.
The Associated Press contributed.