USDA: Deadly pig virus likely carried into U.S. from China

In 2013, a virus started spreading rapidly through farms in the U.S., ultimately killing 8 million piglets and sapping the nation's hog supply by 10%. Now the USDA believes it has found the source of the virus, called porcine epidemic diarrhea virus (PEDv). The virus was nearly identical in DNA to a similar illness in China and was likely carried into the United States via tote bags used in international trade, the agency said Wednesday.

In a report, the USDA put the blame on flexible intermediate bulk containers, which are woven plastic bags used to ship up to 3,000 pounds of goods, according to the Associated Press. The bags are reusable, and investigators surmised they could have been contaminated with compost, fertilizer or water from a farm in China that had been affected by the virus.

"The most probable route of dissemination is in the context of recycled food or feed products through distribution companies who generally service a large network of feed mill customers across the Midwest and beyond," says the report, as cited by Reuters.

But the USDA's report was far from conclusive. The investigators named 17 possible scenarios for how PEDv could have entered the U.S., and more than one was deemed plausible, according to Reuters. The agency was not able to come up with definitive proof that a shipping bag had become contaminated.

The report noted that dog treats made in China were also transported to the U.S. using the same tote bags. China-made treats sickened thousands of pets in the same timeframe as the PEDv epidemic, though an investigation by the USDA and FDA found no link, according to the AP.

PEDv has come under control, and Zoetis ($ZTS) has been marketing a vaccine, but the virus is still a concern in the pork industry. Earlier this year, a new strain was found in Minnesota, prompting fears that the virus is mutating. And some in the industry worry that the USDA isn't doing enough to prevent pathogens from crossing international borders.

"The investigation … was inconclusive, so a pathway is still open for the entry of other diseases such as foot-and-mouth disease," National Pork Producers Council spokesman Dave Warner told the AP. "NPPC remains concerned about this gap in our system for protecting animal health."

- read more at Reuters