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SHIC-Funded Demonstration Project Confirms Viral Survival in Feed

Working with funding provided by the Swine Health Information Center (SHIC), Dr. Scott Dee and his team at Pipestone Applied Research have been studying the risk of virus movement in feed. Early work was all completed in the laboratory and confirmed the survivability of porcine epic diarrhea virus (PEDV) in feed as the vehicle for transmission and transport. More recently, Dr. Dee developed a demonstration project to reproduce the results found in lab studies under real world conditions. In the report summary, results indicated the presence of viable porcine reproductive and respiratory virus (PRRSV), Senecavirus A (SVA), and PEDV in both soy products, while viable SVA was recovered from all five tested feed ingredients. In contrast, survival was limited in the vitamins and amino acid ingredients.

While all results achieved in the lab setting were valid, Dr. Dee noted a need, particularly from producers and governmental agencies, for more information beyond a lab setting. "We wanted to expose the viruses to as many environments as possible in the continental US," he explained. "This was like an actual commercial journey." The current SHIC-funded project saw feed spiked with viruses loaded in containers on a truck and driven all around the US. The trip lasted 21 days, involved 107 hours of transport, and crossed 14 states, covering approximately 6000 miles. From Minneapolis to Iowa to Colorado to Texas, across the southern coast, up the eastern seaboard, and back to the Midwest, the trip exposed the virus-spiked feed to mountainous, western, gulf coast, eastern, and New England environments as well as Midwestern.

Upon the truck's return to Minnesota, the feed samples were tested. SVA was found in every feed ingredient being evaluated. Dr. Dee noted this reflected what had been seen previously in the lab, that SVA - a surrogate of food-and-mouth disease - survives and is stable in feed ingredients. The results for PEDV and PRRS showed they survived in feed as well. This demonstration also confirmed lab results showing soy-based products being supportive of viruses; both organic and inorganic soybean meal were included and all viruses lived well in each. In the end, results from the lab were reproduced in real world conditions.

It is important to note this demonstration project was conducted with great care for the viruses included in the test ingredients. Samples were very well contained in boxes securely loaded in the trailer without risk for spills. There was no other cargo in the trailer and the only stops made were for fuel and overnight rest. "We wanted to protect the sanctity of agriculture," Dr. Dee stated. "These were not foreign animal diseases. We talked to the Board of Animal Health director and USDA. If we were managing the demonstration as described, they were perfectly fine with it."

The amount of feed in this demonstration was small - just 30 grams per test. This allowed for the entire quantity of feed to be tested at the conclusion of the journey so there were no false negatives. Because this was a proof-of-concept project, a larger scale demonstration is next on Dr. Dee's agenda for this fall.

"We're going to do this whole thing again in November, using one ton totes of organic and inorganic soybean meal," he remarked. "We will get away from the 30 gram amounts and into a representative volume producers are dealing with all the time in tons." When these ingredients return, sample testing will be completed. The same route, viruses, and feed products will be used. "This helps bridge the gap from lab to the real world," Dr. Dee concluded. He anticipates the results helping people gain more confidence with evidence viruses can live in feed under a commercial shipping event.

As the world deals with the COVID-19 pandemic, SHIC continues to focus efforts on prevention, preparedness, and response to novel and emerging swine disease for the benefit of US swine health. As a conduit of information and research, SHIC encourages sharing of its publications and research. Forward, reprint, and quote SHIC material freely. SHIC is funded by America's pork producers to fulfill its mission to protect and enhance the health of the US swine herd. For more information, visit http://www.swinehealth.org or contact Dr. Sundberg at psundberg@swinehealth.org.