USDA believes swine viruses were carried in undisinfected reusable containers.
USDA believes swine viruses were carried in reusable containers that were not disinfected.

WASHINGTON – A root cause investigation into how swine enteric coronavirus disease spread in the United States revealed reusable bulk containers as the source of the diseases.

The Animal and Plant Health Inspection Service (APHIS) of the US Dept. of Agriculture said the best scenario for virus entry into the US is through the reuse of Flexible Intermediate Bulk Containers (FIBCs). The containers are used to transport a variety of products such as pet treats, sand for flood control or almost any type of bulk material, APHIS explained. However, the containers are not usually cleaned and disinfected between uses.

“Evidence collected as part of the investigation suggests that the FIBCs could be potentially contaminated in their origin country and, upon arrival in the United States, are likely being reused,” the agency said in a news release. “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.”

APHIS said follow-up testing was completed to provide evidence for this scenario. The follow-up tests also supports the hypothesis that Porcine Epidemic Diarrhea virus (PEDv) was spread in this manner in the US. A study published in the peer-reviewed BMC Veterinary Research journal found that livestock feed can be a carrier of PEDv. The virus killed more than 8 million piglets and spread to herds in more than 30 states after the disease was first confirmed in the US in May 2013.