The USDA investigation suggests large bags used for feed and other inputs could have brought the pig virus to the U.S.
Canadian hog producers are being warned of the risk in reusing totes, the large bags used to deliver feed, seed and other inputs.
Totes, also known as flexible intermediate bulk containers, are considered the possible culprit in bringing porcine epidemic diarrhea virus to the United States from China.
The virus has killed millions of piglets in the U.S. and although spread has slowed since it was first identified in North America three years ago, it continues to affect hog production.
The U.S. Department of Agriculture released the results of its investigation into the root cause of its PED infection last week.
Though not conclusive, it suggested totes that contained goods sent from China could have introduced the virus to the U.S.
It is common for farmers to reuse totes and uncommon for them to be cleaned or disinfected.
Dr. Julia Keenliside, a veterinary epidemiologist with Alberta Agriculture, told Alberta pork producers Oct. 9 that reusing totes can present a biosecurity risk.
“If indeed this is the source, prevention could be quite simple as just not reusing these totes or using disinfection procedures such as dry heat and time,” she said.
The USDA examined feed as the initial source of viral spread, but ruled that out because PED occurred in six different states within two weeks and there was no common feed source.
Dried porcine plasma was also ruled out because those products are not imported from China.
The type of PED that entered the U.S., and then Canada, was identified as a strain existing in China, hence the connection to that country.
“The scenario they (the USDA) are reporting as the most logical is that totes originating in China were contaminated in China somehow with feces or something with the viruses in them and then they were re-used to deliver feed or feed ingredients in the U.S.,” said Keenliside.
The full report from the USDA, entitled Swine Enteric Coronavirus Introduction to the United States: Root Cause Investigation Report, is available at http://1.usa.gov/1QeLH32.