Introducing important work examining the role of contaminated feed as a vector for transmission of foot-and-mouth disease virus (FMDV), a new study, funded by SHIC, the National Pork Board and ARS/USDA, was published in July 2021.* Specifically, the study performed by researchers from ARS/USDA at Plum Island, evaluated the potential risk of incursion of FMDV into naïve pig herds through contamination of feed. Per the study report, the goal of the project was the assessment of the infectiousness (viability) of FMDV in commercial whole pig feed and pig feed ingredients. Additionally, the researchers, led by Drs. Stenfeldt and Arzt, determined the dose required to infect pigs through natural feeding behavior. Finally, the project looked at the ability of select commercially available feed additives to reduce infectivity of contaminated feed. “While comparable research investigating the potential biosecurity risks of imported feed exists for other viral pig pathogens (Dee et al., 2018; Niederwerder et al., 2020; Niederwerder et al., 2019), this is the first comprehensive evaluation of the risk of FMDV infection of pigs through ingestion of contaminated feed under controlled experimental conditions,” wrote the authors.
In discussion of the study, authors noted many conditions must be met for transmission of viral diseases through pig feed to occur. They also acknowledged that understanding these conditions is critical in order to quantitate the associated risk as well as consider preventative measures. Per their report:
• The feed must first become contaminated with the virus.
• The virus in the feed must then remain viable until it is fed, and the quantity of infectious virus must be sufficient to surpass the minimum infectious dose.
• Finally, at least one pig must consume enough virus to become infected over one or multiple feedings.
In this study, these requirements were considered in the context of pathogen incursion occurring before or during transoceanic transport (Dee et al., 2018). The combined output from the current investigation demonstrated that the likelihood of all of these conditions being met will depend on: