In May 2017, the Swine Health Information Center (SHIC) released information from a study it funded showing the potential for viruses to contaminate and survive in feed ingredients. These surprising findings led to on-going research on transmission potential and mitigation. A meeting of stakeholders, including representatives of USDA, FDA, universities, industry organizations, producers, the feed processing industry, and SHIC, was held in June 2018. The objective of the meeting, hosted by SHIC and the National Pork Board, was to review current government policies and regulations and to make recommendations about research to help reduce the risk for pathogen transmission via feed and feed ingredients. A report from the meeting can be read here.
In addition to the prioritization of next steps, the stakeholder representatives heard updates from companies and federal agencies engaged in parallel work. FDA’s Center for Veterinary Medicine and USDA’s Animal Health and Plant Inspection Service both have regulatory authority related to feed safety. And USDA’s Center for Epidemiology and Animal Health will help with a review of the scientific literature and will bring experts together to discuss risk. SHIC is funding university and production company-related research to help define feed risk. And feed processing companies are also contributing to the body of work to help identify feed transmission risk and investigate mitigation. Programs were described and outcomes discussed during the meeting. Details are included in the meeting report.
Mitigation via verifiable controls
The action with the highest priority, mitigation, could include programs for verification of feed component safety prior to shipment from a foreign country. Possible methods discussed and recommended were block chain testing and traceability as well as preventative controls for animal food.
Active foreign animal disease monitoring at ports or importing countries
Active monitoring of imported feed components was ranked second by the stakeholders group. Monitoring for foreign animal disease and other transboundary pathogens at ports of entry, or before shipment from source countries, was discussed. Participants agreed this monitoring should be done at a foreign facility prior to shipment to the US.
Minimum and median infective dose of classical swine fever (CSF), pseudorabies virus (PRV), Senecavirus A(SVA)/foot-and-mouth disease (FMD) during normal feeding behaviors
Determining the minimum and median infective dose of key swine diseases CSF, PRV, and FMD during normal feeding behaviors was named an essential need. Using a National Pork Board grant, this is being done for African swine fever (ASF) at Kansas State University where similar tests for CSF and PRV can take place. Work with FMD must occur at Plum Island Animal Disease Center where SHIC, NPB and USDA-APHIS are co-funding the project. In addition to infective dose, mitigant effectiveness and survivability tests would be completed.
Active domestic monitoring
This monitoring would involve surveys of feed processing mills to measure the incidence of different domestic production pathogens found in these facilities.
Validation of environmental swab tools
Validation for dust sampling sensitivity using different materials, from commercially-available sheets to sponges, swabs, paint rollers, to other tools, would be conducted.
Detectability of other viruses via environmental monitoring
Research is needed to demonstrate the ability to detect viruses using environmental samples at various points in feed processing mills. Previously environmental sampling has been shown to be useful for detection of porcine epidemic diarrhea (PED) virus and SVA and that work would be expanded.
Tote contamination proof-of-concept
Testing for valid ways to sample totes as they carry feed into the country could be to sample the dust of a tote before, during loading, after loading, and after emptying to compare sensitivity of dust sampling to taking feed samples at the same times.
Rotavirus vs. Enterobacteriaceae as an indicator of possible contamination
Enterobacteriaceae are used as an indicator organism for fecal contamination of feed components. This experiment would compare rotavirus, or some other enteric virus, to these bacteria to investigate if it would be a better indicator of viral contamination.
Stakeholders agreed the goal should always be to prevent introduction of a FAD or transboundary pathogen from entering the US. Represented groups agreed about the urgency to investigate, define and mitigate the risk because of its potential as a pathway and the threat it poses to the US swine herd.
Funded by America’s pork producers to protect and enhance the health of the US swine herd, the Swine Health Information Center focuses its efforts on prevention, preparedness, and response. As a conduit of information and research, SHIC encourages sharing of its publications and research for the benefit of swine health. Forward, reprint, and quote SHIC material freely. For more information, visit https://www.swinehealth.org or contact Dr. Paul Sundberg at [email protected].