An emerging pig virus, which has claimed the lives of millions of piglets and raised pork prices nationwide, has spread to Virginia.
Earlier this month, the Virginia Department of Agriculture and Consumer Services confirmed the first case of porcine epidemic diarrhea virus (PEDV) in the state and the U.S. Department of Agriculture announced that U.S. pork producers are now required to report instances of the deadly virus.
PEDV, which has a high mortality rate for piglets, was first recognized in the United States last May and has spread to 30 states.
“The virus affects all pigs, but it has the greatest impact on piglets because they are more likely to suffer from severe diarrhea and dehydration leading to death,” said Dr. Kevin Pelzer, an epidemiologist at the Virginia-Maryland Regional College of Veterinary Medicine at Virginia Tech.
On April 18, USDA announced that it is now requiring pork producers to report cases of the virus and tracking the movement of pigs, vehicles, and equipment leaving affected premises. According to Pelzer, pork producers can help prevent the spread of the virus by following strict biosecurity and good sanitation procedures on their farms. The highly contagious virus spreads through the fecal-oral route when pigs come into contact with other infected pigs or contaminated objects, such as boots or tires, from a farm with infected pigs.
“Pork producers should limit their movement on and off the farm and limit the number of people that come to their farm,” said Pelzer, who is a professor of production management medicine in the Department of Large Animal Clinical Sciences. “Ideally, when visitors come to your farm with a vehicle, you should meet them just outside your property so their possibly contaminated vehicle never enters your farm. If a vehicle such as a feed truck needs to enter the farm, tires should be disinfected prior to entry.”
Although the virus cannot spread from pigs to humans and is not a food safety concern, it has taken a toll on the pork supply and, as a result, consumers are seeing pork prices that are approximately 10 percent higher than before the virus hit the U.S. It takes about five months for a hog to reach market weight.
The national outbreak has reduced the number of pigs being raised over the last several months and, therefore, decreased the number of pigs that will go or are going to market.
“Because the virus is new in this country, the swine population has no immunity to it,” Pelzer said. “Currently, there are no vaccines for PEDV in the United States. Although PEDV vaccines exist in China, we know that there are multiple U.S. strains of the virus and are unsure whether the Chinese vaccines would work against these strains.”
Last fall, a team of researchers led by Dr. X.J. Meng, University Distinguished Professor of Molecular Virology, used strains of the virus isolated from outbreaks in Minnesota and Iowa to trace the likely origin of the virus to a strain from China. The researchers determined that the U.S. strains of the virus likely diverged from the Chinese strains two or three years ago following an outbreak of a particularly virulent strain in China.
Scientists are unsure whether the virus diverged in China before spreading to the United States or was in the country for several years before it became an epidemic. The symptoms — which include vomiting, anorexia, and diarrhea — are similar to another swine disease called transmissible gastroenteritis (TGE) virus. No one knows how or when the virus came to the United States, as swine producers and veterinarians may have originally mistaken the diarrhea outbreak for TGE.
“The only way to tell the difference between the two viruses is laboratory testing,” Pelzer said.
PEDV favors cold environments and thrives during the winter months. It has advanced rapidly from state to state, prompting some researchers to investigate whether it has other transmission routes.
“There is some speculation that the virus may have been in swine feed at some point. Some pigs may have come in contact with contaminated dried plasma, a highly digestible protein fed to baby pigs,” Pelzer said. “This hasn’t been confirmed, but it is a possible explanation for how the virus has spread so quickly.”