© AP Photo/Charlie Neibergall, FileDr. Craig Rowles stands with hogs in one of his Carroll, Iowa, hog buildings.
A virus never before seen in the U.S. has killed millions of baby pigs in less than a year, and with little known about how it spreads or how to stop it, it's threatening pork production and pushing up prices by 10 percent or more.
Estimates vary, but one economist believes case data indicate more than 6 million piglets in 27 states have died since porcine epidemic diarrhea showed up in the U.S. last May. A more conservative estimate from the U.S. Department of Agriculture shows the nation's pig herd has shrunk at least 3 percent to about 63 million pigs since the disease appeared.
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. The federal government is looking into how such viruses might spread, while the pork industry, wary of future outbreaks, has committed $1.7 million to research the disease.