Porcine Epidemic Diarrhea Virus (PEDv) has profoundly affected the U.S. swine industry since it emerged May 2013. Since late January 2014, it has been suspected that PEDv outbreaks have been associated with consumption of PEDv positive feed or feed ingredients. However, information is lacking which confirms the ability of feed to be a vector in PEDv transmission and no data is available which describes the minimum infectious dose of PEDv in a feed matrix. Additionally, it is believed that the normal temperature and retention times utilized by commercial pellet mills will be adequate to mitigate PEDv infectivity; however, no research has been conducted to test this hypothesis. Therefore, the purpose of this project was: 1) determine the minimum infectious dose of PEDv in a feed matrix and 2) determine if the retention time and temperatures used in commercial pellet mills will influence PEDv infectivity. Our results confirmed that feed can be a vehicle for PEDv transmission and that the minimum infectious dose of PEDv in a feed matrix is quite low. A PEDv dose that corresponded to a PCR Ct value of 37 was low enough to lead to infectivity. In layman’s terms, this is theoretically equivalent to 1 g of infected pig feces being diluted in approximately 500 tons of feed. Our results also showed that the pelleting process utilized in many commercial mills can act as a point-in-time mitigation step in PEDv-associated risk prevention plans because none of the virus-inoculated and processed feed lead to infectivity in the pig bioassay model, even though the PCR analysis indicated that PEDv RNA was present in the processed feed. In contrast, the non-processed feed did lead to PEDv infectivity.
For more information, please contact Dr. Woodworth at (785) 532-1157 or [email protected]
