Craig Rowles has become a go-to guy when it comes to the porcine epidemic diarrhea virus (PEDV). That’s because Rowles, partner and general manager of Elite Pork Partnership LLP, an 8,000-head farrow-to-finish operation near Carroll, has been dealing with the virus on several sites the partnership owns.

"This is not what you want to be an expert in, trust me," he said.

PEDV was first de­­tected in herds of pigs in the United States during April 2013. Initial clinical cases were detected in herds in Indiana and Iowa during May 2013. The virus spread rapidly across large geographic...