A lot has to go right to keep the U.S. swine herd healthy. Some producers claim luck as the reason that they have never experienced porcine epidemic diarrhea virus, but luck cannot be the staple of a farm’s bio-security plan.
Though porcine reproductive and respiratory syndrome still has the largest economic impact on the U.S. swine herd, it was the introduction of PEDV that pushed producers to ramp up their biosecurity plans. When PEDV first reared its ugly head in swine barns, producers, veterinarians, and researchers were left to wonder just how it got there.
Scott Dee, veterinarian with Pipestone Veterinary Services and the director of Pipestone Applied Research, has done tons of work on finding ways to keep swine herds healthy, from the research of filtration of barns to looking at feed as a viral conduit into barns. But Dee does not do this work alone. As is the case with many authored research papers, many may receive bylined credit, but there are still many more putting in hours of research.
Research with proof of the concept that PEDV can be harbored in feed led to see if the same virus could make its way to the U.S. along with feedstuffs from Asian markets, where a variety of feedstuffs originate for the U.S. market. Dee and researchers at the Animal Disease Research and Diagnostic Laboratory at South Dakota State University in Brookings proved that PEDV could indeed survive, suggesting a way the pathogen came to the U.S.
So if PEDV can ride the waves, can other pathogens such as foreign animal diseases also survive as stowaways with Asian-origin feedstuffs? Dee and other researchers work off the Swine Health Information Center’s Swine Disease Matrix, a prioritized list of endemic and foreign swine pathogens. Hog producers do not want any disease adding pressure to their swine herd, but the emergence of a foreign animal disease, such as foot-and-mouth disease, could halt all movement of U.S. pork domestically and internationally.
Twelve swine viruses identified on the Swine Disease Matrix were tested for potential to survive an oceanic voyage from China in 11 food or feed products, in addition to two complete feed samples. Stock virus by itself was also tested for its ability to ride the waves to the U.S. shore.
In addition to involvement with Dee’s employer, and closely working with researchers in the SDSU ADRDL, this research is made possible with funding from SHIC. Dee also credits Paul Sundberg, SHIC executive director, with being a driving force behind the research. “I was going to do three viruses,” Dee says. “But Paul said, ‘We need to do 10.’ It’s his big thinking that got this project to where it’s at today. He [Sundberg] had the vision to say, ‘Let’s do it bigger.’ ”
Even under extremely precise conditions within a research laboratory, special care needs to be taken when working with any virus, but especially so with viruses that could cause great loss to an entire industry. Also since the plan is not to have our swine herd exposed to these FADs, researchers are using surrogate viruses, viruses that are genetically similar to the FAD. In this latest study, six virus surrogates were used for the 12 viruses tested.
FMD has not been in the U.S. swine herd since 1929, and it would be detrimental to the entire livestock industry if it were to resurface. So even though Dee and his fellow researchers want to find out if that pathogen could be transmitted through feedstuffs, they could not work directly with the FMD virus. Only researchers at the Plum Island Animal Disease Center off the coast of Long Island, N.Y., can work directly with the FMD virus. Researchers elsewhere wishing to study FMD need to look at surrogate viruses. Diego Diel, assistant professor at the SDSU ADRDL, says Senecavirus is similar to FMD — not only in the clinical signs it presents in pigs but also in its genetic makeup. “Senecavirus and FMD are both from the same family,” Diel says. “They are closely related and have a small RNA molecule as their genome, are related phylogenetically and share biological and physicochemical properties. These criteria were used to select surrogates for other important livestock pathogens to be tested in our model as well”.
Collaborative efforts and virology work is nothing new for Diel, who prior to coming to SDSU three years ago, did two post-doctoral trainings at the USDA Southeast Poultry Research Laboratory and at the University of Illinois, Champaign-Urbana. During these years Diel worked with foreign animal diseases of importance to the poultry and the swine industry.
At SDSU, Diel and his collaborators performed the work with Biological Safety Levels-2 agents. The Centers for Disease Control and Prevention sets BSL lab levels as a way of exhibiting specific controls for the containment of microbes and biological agents. There are four BSL levels — BSL-1 in which lab personnel work with low-risk microbes, up to BSL-4 labs which are rare and employ the highest level of biological safety as personnel work with highly dangerous and exotic microbes. Each BSL level carries with it a more stringent biosecurity protocol than the level below it.
The SDSU lab is a BSL-2 facility, so Diel and his colleagues conducted the work with pathogens that are endemic in the United States, by not with BSL-3 level pathogens like ASFV. That is where Megan Niederwerder, assistant professor in the Kansas State University College of Veterinary Medicine comes in. “The Biosecurity Research Institute on the KSU Manhattan campus is a BSL-3 facility, allowing researchers there to work with viruses such as ASFV. The Kansas National Bio and Agro-Defense Facility Transition Fund provided additional funding to support K-State’s portion of the project.”
“We learned a tremendous amount from the work that Scott [Dee] and Diego [Diel] had already completed, including developing a transboundary model for BSL-2 pathogens. We have been able to expand this work due to the capabilities we have here at Kansas State University, enabling us to translate the model for investigating BSL-3 pathogens,” she says.
Niederwerder tells how collaboration is nothing new on the campus of KSU. “We had formed a collaborative risk assessment group between the College of Veterinary Medicine and the College of Agriculture to include those individuals with viral disease expertise, as well as those individuals with expertise in feed safety and nutrition. It was a natural progression to team with Scott and Diego and work together to investigate both BSL-2 and BSL-3 pathogens in feed.”
A history of collaboration goes back to when Niederwerder was a doctorate student at KSU, working under the mentorship of Bob Rowland. “And when I started my faculty position [in 2015], we naturally began to work together, and I started collaborating with the swine nutrition group on several projects,” she says.
Varied backgrounds, areas of expertise and stage of careers of the many people involved in these projects within KSU, as well as at SDSU, are a benefit to the success of the research. “I believe the beneficial characteristics of this collaboration include its diversity as well as the opportunities for teaching and learning,” she says. “The people in the early stages of their careers may bring new and interesting ideas, and those who are in the later stages of their careers bring years of experience and knowledge.”
This current research project is being completed, and results should be available in the next month.
Great minds collaborating to do great things also get a boost from the best technology available. Things will get even better in Manhattan, Kan., and even better for the U.S. livestock industry, as the NBAF is being built next to the BRI. The $1.25 billion facility, expected to be operational by 2022, will be a BSL-4 lab set to replace the aging Plum Island center.
Knowing that a virus can survive an oceanic voyage is only the first part of the puzzle. Establishing if it’s possible to prevent pathogens — and if so, how — from getting into the swine herd is the next step. On that note, researchers are testing ten different mitigating products, applied at different stages of the simulated oceanic voyage, to determine the efficacy of killing the pathogen virus in the feedstuffs.
Biosecurity is an ever-turning chain, with researchers, veterinarians, producers and swine technicians each playing a vital role in making sure the chain is well-oiled, and operating smoothly to keep the U.S. swine herd healthy.