Last month, Porcine Epidemic Diarrhea virus (PEDv) was confirmed on a farm in Hawaii. Officials are still puzzled as to how the disease crossed over thousands of miles of ocean to the island.

"It was surprising because it was a long distance from your traditional swine channels," Tom Burkgren, executive director of the American Association of Swine Veterinarians, said about the outbreak.

State Veterinarian Isaac Maeda told Reuters in a telephone interview that animal feed from the infected farm is being tested to determine whether it may have transmitted the virus.

"We live out in the ocean," Maeda said. "A lot of things you see on the continental U.S., we don't see out here."

Even with testing, the chances of determining how PEDv arrived in Hawaii are "not looking very promising," he added.

The farm at the center of the outbreak did not use feed containing porcine plasma. Click here to read more from Reuters.

The Hawaii Department of Agriculture initially confirmed the state’s first case of PEDv in mid-November. Hawaii has roughly 230 pig farms statewide. Of those, 70 are located on Oahu. Most are small operations. See, “Hawaii reports first PEDv case”