Dr. Montiel on Risk of African Swine Fever Virus Transmission via Feed

Focus on Feed for Virus Transmission 

I was excited to read the recent review of the risks and mitigations strategies for African Swine Fever Virus in feed by Dr. Niederwerder at Kansas State. It is great to see research emphasize the global impact feed has as a fomite. Feed has long been recognized as a vehicle for pathogens, such as Salmonella. Still, it is essential to note that it has demonstrated capacity as a viral vector in recent years. This latest review of works on virus survival and transmission via feed reinforces the necessity for implementing mitigation strategies in the production of finished feeds. Work done by Dee et al. in 2018 showed that several viruses, including African Swine Fever Virus (ASFV) and Porcine Epidemic Diarrhea Virus (PEDV), can survive in feed ingredients while being exposed to global transport conditions. As industry participants in importing and exporting, we must seek to understand the risks feed ingredients pose to animal health and welfare and the impact they have on our local industry. In times such as now, when we face stress during ingredient acquisition, it is essential to know where our raw materials come from and have a strategy for reducing biosecurity risks that they may present.

Disease Risk From African Swine Fever Virus in Feed

In 2018 work was published determining the infectious dose of ASFV in naturally consumed feed or liquid by Dr. Niederwerder, highlighting the role of feed ingredients and thus, finished feed as a fomite for ASFV. This study showed that a single exposure of ASFV-contaminated feed can cause clinical disease to swine. In feed at the minimum infectious dose, which was four logs high than that of the liquid viral suspension comparison, 40% of the pigs fed contaminated feed tested positive for ASFV. While it is crucial to recognize the transference from artificially spiked feed to an animal does not perfectly illustrate how a natural viral load may contribute to the incidence of disease in livestock, it does prove that feed has merit as a vector for ASFV. In fact, the researchers hypothesized that feed potentially carries a higher risk despite requiring a higher viral load. In most operations, feed production is at the center of everything. Feed is transferred from its production site to multiple farms consistently and frequently, presenting the perfect opportunity for increased exposure events. With every added exposure, the level of feed-bound virus required to cause disease becomes lower. Feed and feed ingredients are constantly moving from centralized production areas to farms, and contaminated feed resulting from unmitigated production carries a high risk and likelihood of being brought to many farms and fed to even more pigs.

Feed Mitigation Preserves Biosecurity 

There has never been a more critical time to consider feed sanitation measures, especially with the awareness of the role feed plays in transmitting viral diseases. As seen from Dr. Dee’s transboundary model work at Pipestone Veterinary Services, feed ingredients, like soybean meal, have been repeatedly shown to sustain viral pathogens and serve as a global transmission risk. Current industry conditions are making the acquisition of feed ingredients more complex, and it is crucial to recognize the risk that all domestic and foreign sourced ingredients have on feed leaving mills, widely spreading to a vast number of livestock. As an industry feed pathogen and animal health professional, I look forward to investigating and understanding viral behaviors in feed and observing how the industry receives developments on the viral transmission front. As someone who respects feed as a fomite, I am proud to work with Anitox to continue making feed sanitizing solutions widely available to control the spread of pathogens and disease via feed and feed ingredients.

• • For more information on how feed sanitizers can protect feed visit our website. 

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