Manitoba’s worst PEDv year on record may be drawing to a close, but the pork sector already has a wary eye on what might be the next big disease threat.
In 2016, veterinarians identified a new, aggressive strain of PRRS (porcine reproductive and respiratory syndrome) in Manitoba. A total 15 sites have been impacted so far, causing both sow and pre-weaning mortality.
The disease is best known for its blue ears, respiratory problems, premature and stillbirths, abortions and mummified piglets, but also causes fever and anorexia, respiratory problems, lower immunity and diarrhea.
“We’re looking at about six months or more before production returns to normal after a PRRS outbreak,” Dr. Egan Brockhoff, veterinary counsellor for the Canadian Pork Council, told Manitoba pork producers in November.
The strain likely came from the United States through livestock transport or biosecurity lapses, Brockhoff said, pointing to genetic similarities to strains in the U.S.
Brockhoff was the main speaker at this year’s Manitoba Pork Council membership meetings.
“PED virus, as devastating and as horrible as it is, is maybe a little more straightforward than PRRS virus,” he said. “PRRS virus is a complex virus that moves and shakes in multiple different ways. It can move from pigs in both vertical and horizontal patterns — so mom to babies, in utero, nose-to-nose contact, aerosol.
“This virus can move through oral contact. It can move through nasal contact. It can move through vaginal contact through the introduction of semen, injection — needles, sharing needles between animals — can spread PRRS virus. Catheters can spread PRRS virus when you’re breeding. Not changing your gloves could spread PRRS virus when you’re doing a vaginal exam.”
Outside of the usual suspects (manure on shoes, trailers, etc.), Brockhoff pointed to PRRS in semen or milk, saliva or urine and through the air up to 9.5 kilometres, depending on how aggressive the strain.
After infection, clinical signs begin to show within two to five days, reaching a peak within 10 days.
Once contracted, animals shed virus for up to 99 days and a boar can infect sows for three months through semen. In a closed sow herd, Brockhoff estimates it takes 200 days until the pathogen washes through the herd.
“This is an expensive disease,” he said. “This disease costs your farm a fortune.”
Research cited by Brockhoff puts the cost of PRRS at $570 per sow in Canada, counting lost piglet cost and sow mortality.
The newly aggressive PRRS is still not as devastating as the highly pathogenic PRRS that ripped through Asia in 2007-08 and continues to be a concern, Brockhoff said.
“This disease can be prevented. It can be controlled and it definitely can be eliminated from farms. The problem is that the devil is always in the details, and Jenelle’s presentation today showed us that the devil is in the details,” he said, referencing MPC swine health programs manager Jenelle Hamblin and her update on PEDv in the province. “Little people making small mistakes in terms of their biosecurity can have a huge cost on introduction and, of course, once that biosecurity cascade is broken, we have welfare issues; we have disease issues; we have mortality issues and, of course, the farms have productivity issues.”
Despite the wealth of ways PRRS may enter a barn, Hamblin says biosecurity principles are largely the same whether protecting against PEDv or PRRS.
“Biosecurity doesn’t really play favourites when it comes to a virus or any type of pathogen,” she said. “I don’t think there’s a lot of difference that you can do between pathogens or threats other than just making sure you’re looking at each aspect of your operation for potential risks and assessing those risks.”
The Manitoba Pork Council plans to fold PRRS into its Manitoba Coordinated Disease Response program, launched this year in reaction to the now 80-case PEDv outbreak.