CHICAGO (Reuters) — Investigators may never determine how a highly contagious virus that has killed an estimated 10 percent of U.S. pigs entered the country for the first time last year, the U.S. Department of Agriculture’s top veterinarian said Monday.
Porcine epidemic diarrhea virus has wiped out an estimated seven million pigs, infected farms in 30 states, and helped push pork prices to record highs since the first case was found in Ohio in April 2013. A second strain of the virus and a separate disease called swine delta coronavirus also have been discovered.
“That pathway that it came in on, and the same pathway that delta corona came in, is very concerning to us,” USDA’s chief veterinary officer John Clifford told Reuters. “We’re doing all that we can to try to identify that. We may not identify it, though.”
PED is not a threat to humans or food, according to the USDA. But its success in getting past inspectors at U.S. borders and other safeguards has alarmed government officials, private veterinarians, hog producers and meat processors. They fear more serious diseases could enter by similar means.
Clifford said that trying to figure out how PED entered the country is difficult because there are so many potential pathways.
He added that USDA’s ability to track how the virus entered and spread was hampered because veterinarians were not required to report cases. The USDA has said international regulatory standards do not require reporting of PED.
Following the initial outbreak, the hog industry also preferred to have private veterinarians handle cases rather than calling in the USDA, Clifford said.
“Frankly we don’t have good quality data all the time,” he said.
Clifford’s comments came as he and U.S. agriculture secretary Tom Vilsack prepare to travel to Des Moines, Iowa, this week for the annual World Pork Expo, a major industry gathering. They are expected to face questions about the agency’s handling of PED, which was officially identified in May 2013.
“Back in May, there were no rules about who would do what,” said Paul Sundberg, vice president of science and technology for the National Pork Board. Because the virus was not a disease that required USDA reporting, “the obvious thing was for the producers to continue to work with their veterinarians,” he said.
Some producers and veterinarians have criticized USDA for waiting until April 2014 to announce it would require U.S. veterinarians to report new cases. The agency has not laid out guidelines for compliance or started collecting data yet.
PED can be transmitted from pig to pig by contact with pig manure and from farm to farm on trucks. Scientists believe it is also likely spreading through animal feed or feed ingredients, such as plasma from pigs’ blood.
Clifford said USDA believes any PED particles in plasma are inactivated during processing, but feed could potentially be contaminated after it was processed.