USDA describes risk of FMD virus transmission by swine feed
By David Fairfield, Senior Vice President, Feed
The U.S. Department of Agriculture’s (USDA) Foreign Animal Disease Research Unit recently published a journal article to describe the risk and mitigation of foot-and-mouth disease (FMD) virus infection of pigs through consumption of contaminated feed.
The article provides information obtained during USDA’s research to: 1) investigate the ability of FMD virus to remain infectious as a contaminant of complete swine feed and select swine feed ingredients; 2) establish the minimum infectious dose required to cause FMD in pigs; and 3) evaluate the effect of select commercially available feed additives in reducing FMD virus infectivity.
Findings from the research demonstrate that FMD virus may remain infectious in feed ingredients during durations compatible with transoceanic transport, and that importation of soybean meal is a sensible target for enhanced biosecurity measures.
Some findings from the research include:
• FMD virus can remain viable as a contaminant in swine feed ingredients through 37 days.
• Viability of FMD viruses was greatest when soybean meal was the carrier.
• Sal CURB®, a formaldehyde-based feed additive approved in the U.S. to control Salmonella, effectively reduced the infectivity of FMD virus in contaminated whole feed within 24 hours at room temperature.
• GuardianTM, a lactic acid-based feed additive, reduced FMD virus infectivity in feed, despite questionable reduction in viral viability as demonstrated by an in vitro study.
• CaptiSURETM, a medium chain fatty acid mixture feed additive, had little to no anti-FMD virus activity in vitro, and the compound was not further evaluated in vivo (feeding contaminated feed to pigs).
• FMD virus introductions through import of contaminated feed products is plausible, that addition of additives to feed may mitigate this risk, and that the risk of infection varies depending on the contaminated product, the viral strain, and the feeding conditions.