Biosecurity measures undertaken by all sectors of the hog industry have managed to hold the line against the highly contagious porcine epidemic diarrhea virus, (PEDv).
Manitoba has experienced just one infected premise in Manitoba and two positive swabs at high hog traffic areas, said Karl Kynoch, chair of the Manitoba Pork Council.
“That’s hugely positive and it goes to show that the biosecurity being delivered on Manitoba farms is actually working,” said Kynoch, in a PED town hall conference call March 21.
Dr. Glenn Duizer, Manitoba’s acting chief veterinarian, said that “traceouts” of 60 sites that have had some contact with the infected farm have all tested negative.
Environmental sampling since Feb. 1 on nine high-traffic assembly yards, packing plants and truck wash stations sites for a total of 429 samples has turned up two positives. To date, no farms have been found to be infected after followup surveillance.
“High-traffic sites need to be considered positives because of their level of contact with sites outside of Manitoba,” said Duizer, who added that environmental testing would continue.
Andrew Dickson, MPC general manager, said that trucks returning from deliveries of live hogs to farms in the United States were being sealed at the border and directed to accredited wash stations where they are properly washed by trained staff.
However, trailers coming back from packing plants south of the border represent “a gap” in the program, because Canadian Border Services Agency regulations do not require them to be sealed.
“We’re encouraging them to have their vehicles properly washed and disinfected at stations in Manitoba, and we’ve had excellent co-operation from them so far,” said Dickson, who added that he hopes the federal government will update border regulations.
“If we keep this up, we can hold this disease at bay,” said Dickson.
Dr. Craig Price, Alberta-based regional director for the Canadian Food Inspection Agency, said that confirmation of whether spray-dried porcine plasma and other pig-based products in pelleted feed could serve as a vector for spreading PED infection continues to be elusive, despite initial results that found that one lot of plasma from the U.S contained the virus and was deemed capable of infecting pigs.
“The lab test wasn’t able to demonstrate that feed could transmit PED, and that’s a bit different from saying that the feed did not transmit PED,” said Price.
Lab testing, he added, is a process of exclusion or confirmation, but “in this case we weren’t able to confirm it as a vector.”
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“But that doesn’t mean that we can say it wasn’t a vector,” added Price. “We still have a provincial epidemiologist working on the bigger picture of what the role of feed is in the transmission of this disease.”
The CFIA is still working with its counterparts in the U.S. to try and establish what happened with the particular lot of plasma that has since been recalled.
“Does the ingredient itself have an inherent risk for transmission of the disease, or was there something else going on? That I can’t answer for you today,” said Price.
Dr. Doug MacDougald, a veterinarian with South West Ontario Veterinary Services, said that Canada now has a total of 35 PED-infected sites.
The 24 cases were either sow or nursery production sites, and 17 of the first 18 cases, along with a site in P.E.I., were directly linked to the recalled plasma that was found to contain live PED virus.
The first infected herds are now starting to wean a new crop of piglets, which shows that infected sites are out of commission for about a five-week interval.
Second virus surfaces
After extensive cleanouts, many of the previously infected nurseries are now filled with negative pigs, but testing will continue.
Finishers, from farrow-to-finish herds that were infected, are now at the six-week post-infection stage where viral shedding typically ends.
“We are hoping to find little to no virus,” said MacDougald, adding that once past that stage, the risk of spreading the disease will be much lower.
However, Delta coronavirus, a second virus related to both the PED and TGE coronaviruses has been diagnosed at six sites by Ontario’s Agriculture Ministry. First identified in the U.S. in February, Delta coronavirus is “distinctly different” with milder clinical signs which may make it more difficult to detect at the farm level.
“Very little is known at this point,” he said. “But the take-home for all of us is that we now have had two new swine viruses in Canada in the last two months.”
The national swine industry’s health and biosecurity is being “compromised” by “a portal” that is allowing new viruses into North America, said MacDougald, and that means there is also a risk of more serious foreign animal diseases arriving in the future.
“I see this as an incredibly urgent situation that we need to address before we have another virus here,” he added.