USDA thinks it has found the source of the devastating PED virus that killed more than 7 million pigs in 2014: contaminated bulk bags used for animal feed.
In a report released last week, USDA’s Animal and Plant Health Inspection Service explained how these bulk bags could have resulted in a disease epidemic that ended up costing the U.S. between $900 million and $1.8 billion, according to one Purdue agricultural economist.
“After entry in the United States, PED was discovered in six locations within approximately two weeks. The locations were geographically separated and did not have epidemiological links through common age groups, production types, companies, ration formulations, feed mills, feed products, vehicles, veterinarians, or other visitors,” the APHIS report said. “However, one factor is common to most feed mills and represents a potential mechanism for moving (swine enteric coronavirus diseases) across various parts of the country. This is the practice of using recycled feed or food products in the ration formulations. These products are varied and include dairy products such as cheese or whey, dried distiller grains, wheat midds, bakery products, human food products such as breads and pasta, soybean hulls, scrap pet food, and many others.”
Those products are frequently shipped in bulk bags known as “flexible intermediate bulk containers," or FIBCs.
Made of woven polyethylene, they can hold 1,000 pounds to 3,000 pounds of feed, soybeans, pet treats, grains, or other materials. Lightweight and durable, these bags are easily refilled and reused for other products once they are emptied.
And, the bags have typically not been cleaned or disinfected between uses.
According to APHIS, the bags could have picked up the virus in the origin country in a variety of ways, including being carried in a contaminated truck, exposed to “irrigation or flood waters containing organic fertilizer (i.e., pig manure)” and other sources. Then, once the bags arrived in the U.S., so did the virus. “Once a contaminated (bag) or its contents are delivered to a local mill that manufactures pig rations, the (bag) or its contents would contaminate feed or ingredients destined for delivery to the farm,” the report said.
And, as the spread of PED shows, that seems to have happened over and over again.
(While the strains of PED virus that appeared in the U.S. appear to be similar to those in China, the APHIS report also said that “a definitive source of the viruses identified in the United States has not yet been determined.”)
What can hog farmers do to protect their herd from future outbreaks of PED? Stop “recycling, reusing, and reducing” when it comes to bulk bags containing feed.
“If the (object) moving the virus is indeed the FIBC, not reusing or sanitary management prior to reusing the bags could be an effective intervention,” the report said. “Further study is necessary to identify cleaning and disinfection procedures that might be appropriate, but the answer could be as simple as not reusing the bags or yet to be determined disinfection procedures such as dry heat prior to reusing the containers.”
Do you think contaminated bulk bags could have spread the PED virus? What do you think of the recommendation that bags are either discarded or disinfected after uses? Let us know in the comments.