A new strain of Porcine Epidemic Diarrhea virus, or PEDv, has been identified in samples taken from Illinois and Missouri, a top veterinarian at Iowa State University said on Monday.
"We found that there is a variant out there that appears to be quite different than the original," Rodger Main, the head veterinarian of Iowa State University's veterinary diagnostic lab, told Reuters on Monday.
More research needs to be completed, however, to determine if the new variant is a mutation or a different introduction of the original virus.
"There hasn't been a tremendous amount of sequencing completed and there will be additional work to determine if we can truly understand where it came from," he said.
PEDv, a highly contagious and potentially fatal pig virus, causes diarrhea, vomiting and severe dehydration. It is transmitted orally and through pig feces.
The virus does not affect humans, however, and U.S. federal officials have determined meat from pigs that survive the virus is safe to eat.
While older pigs have a small chance of survival, the virus kills 80 percent to 100 percent of piglets that contract it. There are no official figures for pigs lost to the PEDv in the United States, but up to 4 million pigs may have died from the virus, according to industry analysts' estimates.
Some U.S. meat processing companies have said the virus, first discovered in the United States in April 2013, is beginning to impact their bottom lines as it contributes to higher priced pork and is trimming U.S. hog supplies.
The Unites States is the world's largest pork exporter. PEDv has been confirmed in 23 of the 50 U.S. states and was confirmed in Canada two weeks ago.
Confirmed cases of PEDv across the U.S. Hog Belt recently jumped by its highest weekly total since it was discovered, according to USDA's National Animal Health Laboratory Network.
(Reporting by Meredith Davis, editing by G Crosse)