Since the first identification of the porcine epidemic diarrhea virus (PEDV) in the U.S last spring, the disease has posed significant challenges to the nation’s swine industry. PEDV is not a zoonotic disease and does not affect food safety, according to the USDA. However, infection with this highly transmissible virus can cause tremendous financial losses to pork producers, says the National Pork Board, which has spent $1.1 million on research related to PEDV.
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Trucks and trailers hauling pigs to market have been identified as important sources of cross-contamination with PEDV. Now National Pork Board research has identified alternative methods for reducing the risk of PEDV transmission from trailers, short of the “gold standard” of power-washing, disinfecting and heat-assisted drying that is used for only some trailers in the industry.
“We are not suggesting that producers stop power-washing, drying, and disinfecting if they are doing that,” says Derald Holtkamp, DVM, MS, an associate professor at Iowa State University College of Veterinary Medicine in Ames, Iowa. “The industry does not have the resources to wash, disinfect, and dry every trailer, especially the ones that haul the market hogs, so in the field those trailers may never get washed. Our study was looking for alternatives for those trailers.”
Holtkamp and colleagues at Iowa State University found that certain combinations of time and temperature can be sufficient to inactivate PEDV in swine feces on metal surfaces similar to those found in livestock trailers that have been scraped but not washed. Heating trailers to 160 degrees Fahrenheit for 10 minutes or maintaining them at room temperature (68 Fahrenheit) for seven days were found to be effective combinations.
The study is being prepared for peer-reviewed publication, Holtkamp says, but in the meantime its final results and conclusions have been posted on the National Pork Board website.
“These alternatives to full-blown washing, drying, and disinfecting can be practical for pork producers, although we think we can do better,” Holtkamp says. “We’re already looking at other alternative time and temperature combinations that might be more cost-effective.”
He noted that heating to 160 Fahrenheit “takes a lot of propane or gas,” so maintaining that temperature for 10 minutes can be expensive, and there is potential to damage the trailer. The investigators are trying to determine whether some other combination, such as a lower temperature maintained for a longer period of time, might also be effective.
The other effective combination identified could be a good alternative for smaller producers, he says. “For a producer who hauls one load a week, if they currently store the trailer outside or in an unheated shed, the recommendation would be to scrape the trailer and get it into a heated shed for the seven days. That would be a reasonable strategy.”