Tissue samples from the latest case will be examined to determine if it is a hog or bird virus, says epidemiologist
Ontario confirmed another case of porcine epidemic diarrhea Feb. 20 on a farrow to finish operation in Oxford County.
The deadly viral disease has been contained mainly in Ontario and Quebec, but other provinces continue to collect samples at hog assembly yards, truck washes, processing plants and other high traffic areas, Alberta veterinarian Dr. Egan Brockhoff of Prairie Swine Health Services in Red Deer said during a conference call Feb. 25.
“It is not moving extremely rapidly and that is because of the hard work pork producers and industry have been doing to keep it from widespread movement,” said Brockhoff.
Alberta has collected more than 6,500 samples and found positive samples in pigeon and sparrow feces. These samples have been forwarded to the national microbiology laboratory in Winnipeg, where DNA tests are being run to see if it is a pig or avian virus.
“We are not sure whether we are seeing again a new virus or a bird virus, but we will have to follow this one,” said Dr. Julia Keenliside, a veterinary epidemiologist with Alberta Agriculture.
Saskatchewan found its first positive delta corona virus sample in manure collected at a loading chute that came from out of province, she said.
Manitoba has had five farms in-fected with PED, but investigators do not know how the virus entered the province.
“They have been able to identify there are some biosecurity breeches but again, if you look at any operation very closely you will be able to identify something,” Keenliside said.
“Ninety-five percent of the time the biosecurity on these operations is excellent, and every once in awhile there is a slip up,” she said.
Trucks remain a major focus be-cause pigs are moved across the western provinces and into the United States. Manitoba gets a lot of truck traffic from the U.S., which is a likely source of PED because the disease is endemic there. About 100 cases cropped up in the U.S. every week this winter, but the virus appears to have slowed down because of greater biosecurity awareness and a vaccine program.
As well, a pilot project is auditing truck wash stations in the prairie provinces.
“We have found there is lots of opportunity for improvement and education in the truck wash facilities,” said Brockhoff.
Many are washing trucks correctly, but investigators also noticed that some do only a cursory job and may not use soap or disinfectant.
“We see the odd trailer that just get fire hosed out,” he said.
“That of course increases the risk for everyone else following you.”
As well, producers are still warned to avoid using dried porcine blood plasma in feed. The World Organization for Animal Health has said the risk is negligible, but practitioners are being more cautious.
“Negligible risk is not zero. Negligible risk has cost the Ontario and Quebec pork industries millions in lost production and lost piglets and increased disease challenge,” said Brockhoff.
“Although the risk is low, the outcome is devastating for a lot pork producers.”
Millions of pigs fed on the Prairies received blood plasma and suffered no consequences, but dried bovine plasma from plants that only handle bovine products may be better. The plants should be validated to show they are free of PED and that no cross contamination is occurring at these plants.
“We understand the good science behind blood plasma processing and the safety that it should impart, but there has still been no clear explanation or speculation as to how live corona virus, PED ended up in blood plasma products in a mill in Ontario,” said veterinarian Dr. Frank Marshall.