By Scout Nelson
Swine transportation plays an important role in moving pigs from farms to harvest plants. However, the trailers used to move market hogs can also carry viruses from one location to another. New research from the University of Minnesota is helping the swine industry better understand how this contamination happens and how it may be reduced.
Lucas Ferreira, a PhD student at the University of Minnesota College of Veterinary Medicine, has spent nearly two years studying swine trailer contamination. Working with his advisor, Cesar A. Corzo, Leman Chair in Swine Health & Productivity, Ferreira focuses on swine health and diseases that can affect pigs and the pork industry.
His research looks at several viruses, including porcine reproductive and respiratory syndrome virus (PRRS), porcine epidemic diarrhea virus (PEDV), porcine deltacoronavirus (PDCoV), and Seneca Valley virus, also known as Senecavirus A (SVA).
These viruses can cause serious health problems in pigs. PRRS can lead to respiratory disease and reproductive problems, while PEDV and PDCoV can cause severe diarrhea. SVA can cause disease signs that may include vesicular lesions. These diseases can also create major financial losses for pork producers and the wider swine industry.
“We know those trailers are going to the farms and getting the pigs to bring them to facilities,” Ferreira explains. “But nobody knew if those trailers leaving the facility were contaminated, how often it was happening, or the type of factors that might be related to it. The reality is there was no data —not just in the United States, but internationally.”
Ferreira conducted the study at two swine harvest facilities in the Midwest. The research team visited the facilities every two weeks and collected samples to determine how often trailers became contaminated during unloading.
The team collected three environmental samples. One sample came from the dock area at the harvest facility. Two other samples came from inside a trailer, with one collected before the pigs were unloaded, and another collected after unloading.
Researchers also asked truck drivers about their trailer-washing practices. This information helped the team study possible links between trailer cleaning and virus contamination.
“We found that the trailers are leaving more contaminated than when they arrive,” he says. “Both in number of trailers, but also in number of pathogens. Sometimes the trailer will arrive with just PRRS, and then the trailer will leave with PRRS, SVA and PDCoV.”
According to the research Ferreira led, SVA can be found on market hog trailers throughout the year. The percentage of trailers contaminated after unloading is often similar to the percentage of contaminated loading docks. This finding suggests that contamination may happen mainly during the unloading process.
Contamination rates are higher during the summer and fall than during the winter and spring. Another concern is that some trailers carrying SVA after leaving the harvest plant are not washed before making another trip.
“We were expecting contamination to occur, but the numbers are so high,” he says. “The amount of trailers leaving the plants contaminated was really significant.”
Ferreira says the research can also help the swine industry prepare for diseases that are already present in the United States. Better information about trailer contamination may also help the industry respond to a foreign animal disease if one enters the country.
“At the end of the day, we want to decrease the level of contamination that is currently being observed,” says Ferreira, who adds that more research is needed on cleaning and disinfection protocols for trailers and the plants. “We want to make sure that the pigs are healthy, that the trucks are not getting contaminated at current levels, and that the swine industry is better prepared to deal with different pathogens. Because if something happens and foreign animal diseases get into the country, what happens if those pathogens end up in the harvest plant facilities? We now know contamination is happening at alarming levels, and we want to avoid that.”
The research was funded by the Swine Health Information Center (SHIC), the University of Minnesota Swine Disease Eradication Center (SDEC), and the American Association of Swine Veterinarians (AASV) Foundation.
Photo Credit: istock-srdjan-stepic
Categories: Minnesota, Livestock, Hogs