The virus that caused an epidemic that swept U.S. hog farms probably entered the country in contaminated Flexible Intermediate Bulk Containers that carry many types of cargo, says the USDA. “They are designed to be reused. It is not a common practice to clean and disinfect these FIBCs between uses in the United States,” said USDA’s Animal and Plant Health Inspection Service in a summary of its investigation. “If a contaminated FIBC was used to transport bulk feed or ingredients to the swine feed mill networks, a small bit of contaminated material could have been mixed into feed destined for many locations and spread the virus onto farms.”
The USDA said its testing supported the theory that the Porcine Epidemic Diarrhea virus, which killed 7 million piglets in 2013 and 2014, could have survived travel to the United States and then infected pigs.