Pork producers in several states experienced a setback this summer.
A new virus, Porcine Epidemic Diarrhea virus (PEDv), caused illness and mortality in pigs.
Similar to Transmissible Gastroenteritis virus (TGEv), PEDv spreads via feces, but it is not a public health or food safety concern.
Ingesting a microscopic virus particle contained in a small amount of feces is all that is needed to infect a pig.
The most common sources of contaminated feces are pigs, trucks, boots, clothing and other inanimate objects (fomites), according to the Iowa Pork Industry Center, one of many sources for information on PEDv.
Piglets are especially susceptible to PEDv.
In 24-48 hours after exposure to the virus, suckling and early-weaned pigs begin scouring and vomiting.
They soon become dehydrated and die. The mortality rate in suckling and early-weaned pigs in naïve herds can reach 30-100 percent.
About 1-3 percent of older nursery pigs and grower hogs may die from PEDv due to watery scours and dehydration.
In heavier finishing hogs, producers may be unaware that the hogs are clinically ill. These pigs may have loose stools and then spontaneously recover.
After the pig becomes sick, the virus is shed for seven to 10 days. In herds that continue to pass around the disease, loose stools may occur on a long-term basis, hurting feed efficiency.
Currently, there is no approved vaccine in the U.S. to provide protection against PEDv.
According to the American Association of Swine Veterinarians, between May 13 and Aug. 11, 2013 there were 497 U.S. diagnostic cases that tested positive for PEDv in 17 states.
Minnesota had 40 of those cases.
Each case could represent hundreds of piglets at a farrowing operation, but there is no count of how many pigs died this summer from the virus.
Premise ID reporting has not been required, because PEDv is not a human health or food safety concern. It is strictly a production disease. The virus is restricted to the pig intestinal tract.
Since early June, the National Pork Board has committed $800,000 toward research and education of PEDv, as well as for coordination efforts, said Karen Richter, National Pork Board president, Montgomery, Minn.
The Pork Checkoff board plus many agencies are working with volunteer producers to learn more about the disease, discover effective ways to contain it, and eliminate it from specific sites.
“From the time it has shown up and was diagnosed in mid-May, we have been encouraging farmers to step up their biosecurity measures, especially getting those trucks completely cleaned and disinfected – especially coming from the plants,” said Richter.
Minnesota producers are primarily working with their veterinarians, who send tissue samples to the University of Minnesota Veterinary Diagnostic Lab (VDL) for virus detection. The lab developed the first rapid diagnostic test to detect either PEDv or TGEv, providing producers with test results in 24 hours.
“We have no way of estimating the number of pig mortalities, but the reporting system is improving as we speak,” said Dr. Jim Collins, DVM and director of the VDL, professor in the College of Veterinary Medicine, and an expert in food animal diagnostic medicine and infectious diseases.
PEDv was first diagnosed in 1971 in Great Britain. There have been outbreaks in Europe, and it has been found in Asia since 1982, according to information from the Iowa Pork Industry Center.
The USDA has been working with veterinary diagnostic labs, veterinarians, swine producers, animal health officials and swine industries to learn how PEDv got into the United States.
“We do know genetically, that the virus is extremely – at least the one we’ve sequenced so far – is extremely close to a strain in Thailand and China – so the Asian strain,” Collins said. “There is definitely an Asian similarity in the sequence of the virus – like 99.4 percent the same as the virus in Asia.”
The main location to find information about PEDv is online at www.pork.org.
The lower right corner of the home page includes the Pork Checkoff’s collection of PEDv information and resources.
In swine units that have tested positive for the disease, veterinarians have prescribed a sow herd closure and exposing the breeding herd to the virus. The exposed sow can pass on protection to suckling pigs through PEDv neutralizing antibodies in milk.
The swine industry also believes that farms with very stringent biosecurity can keep PEDv out.
It is possible to inactivate PEDv by heating surfaces to 150 degrees F for more than 10 minutes. Sanitizing surfaces with a disinfectant such as bleach and thoroughly drying surfaces can keep the virus from traveling.
Some biosecurity methods include spacing out visits to separate hog barns by at least 12 hours, and limiting visitors.
Showering before entering a hog barn, changing all clothing and boots or shoes, removing jewelry, and wearing hair nets or caps are essential protocols.
Fumigation of supplies and equipment, plus eliminating any contact with transport vehicles are also conducted as biosecurity methods.
“At high levels of the genetic pyramid, they have extremely high levels of biosecurity and have adopted all of these procedures already,” said Collins. “The question is how far down in the production system can we push those levels of biosecurity.
“There is a cost. There is a cost in time, labor and equipment, so it’s a question of how can we push that level of biosecurity down the system, from the high healthy herds to the lowest level, and have it make economic sense.”
Fighting PEDv is sometimes as simple as recognizing biosecurity breaches in plain view.
A recent study by the University of Illinois across six pork processing facilities showed that 17.3 percent of trailers were contaminated with PEDv prior to unloading finishing hogs. Upon leaving the processing plants, an additional 11.4 percent of all trailers were contaminated, potentially taking the virus back to their own herds.
“This data suggests that harvest plants and similar livestock collection points serve as an effective method of contaminating fomites with PEDv and could play an important role in expanding the outbreak of PEDv in the U.S.,” wrote Dr. J.F. Lowe, DVM, MS with the University of Illinois, College of Veterinary Medicine.
The heartache and the economic losses that pork producers have suffered this summer cannot be measured.
Despite the hurdles, producers have worked hard to keep pigs safe from disease by using confinement systems, high quality genetics, good handling techniques and biosecurity.
Now the swine industry is working together find the answers to devastating PEDv.
“Everybody is mobilizing. Resources are being allocated. People are cooperating,” said Collins. “The whole system will get better. The ability to respond will get better. Our ability to manage the data will get better.
“It’s not real comforting to the producers to hear that, but it’s a fact. It’s reality. I’ve never seen such good cooperation as I have between the Universities, USDA, and all of the regulatory agencies.”
Collins encourages pork producers and the pork industry to attend the 2013 Allen D. Leman Swine Conference, Sept. 14-17. To register – http://www.cvm.umn.edu/vetmedce/events/adl/Register/home.html has more information. The conference will focus on Porcine Epidemic Diarrhea Virus.