As the BBC reports, some suspect pig feed of playing a role in spreading the virus. The news agency says efforts to combat it have been complicated by "the use of dried pig blood in feedstuffs that are given to weaned piglets."

Fallout from the virus has sparked outrage and controversy in the U.S. — particularly after a video emerged in February that showed what the Humane Society called a "piglet smoothie" made from infected animals being fed to sows at a farm in Kentucky.

As NPR's The Salt reported, "Hog farmers and veterinarians say that while feeding the guts (or stool) of dead piglets back to sows may sound icky, it's the only option they've got to keep the dreaded PEDV from decimating herds and the whole of the U.S. hog supply."

The PED virus is extremely potent and hard to contain. Here's how Amy Mayer of Harvest Public Media described it in January:

"Since its arrival, PED has been spreading relentlessly, not unlike how a cold can rip through a preschool classroom even if kids are required to wash their hands. PED spreads within barns and from farm to farm, even when strict biosecurity measures — hand-washing for livestock workers — are in place. That's because it can survive in tiny bits of manure that travel on boots or trucks."

According to Reuters, "China, the world's No. 1 pork consumer, and Japan have already imposed 'temporary restrictions' on U.S. pig imports until their ministries reach deals with the United States on testing animals, a trade group said."

Copyright 2014 NPR.

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Deadly Virus Sparks French Ban On Live Pigs From U.S.