Canadian officials believe that three swine diseases are working in tandem as postweaning multi-systemic wasting syndrome (PMWS) spreads across Ontario.

PMWS is sweeping into eastern Canadian swine herds, along with increased incidence of porcine reproductive and respiratory syndrome (PRRS) and H3N2 swine influenza virus (SIV).

Robert Friendship, DVM, University of Guelph, says 54% of the herds he tested now have H3N2, compared with none a year ago.

Stratford, Ontario swine veterinarian George Charbonneau reports that 22% of the tested herds infected with circovirus (PMWS) are also infected with H3N2 SIV, and there has been a tripling of PMWS cases.

Gaylen Josephson, DVM, a retired government disease specialist now working for the Ontario Pork Industry Council (OPIC), believes that most of the province's herds are infected with circovirus, but they simply aren't showing signs of disease.

Josephson suggests that the new strain of PRRS being identified came from Europe, because genetic typing at the Animal Health Laboratory at Guelph indicates it's 98% identical to the new strain that has swept the United Kingdom and France, and 99% identical to the strain in Quebec.

Disease Losses

The losses in Ontario due to PRRS have proved devastating to some herds. Martin Misener, DVM, of the Millbank Veterinary Clinic, says abortion rates in sows have reached 65% and death losses of 15-40% are common.

He says 17,000 of the 80,000 sows the clinic oversees are infected. PRRS losses have run as high as 25%.

Misener says it's possible to get rid of the disease, but hog density in parts of Ontario make it difficult.

“Gilt isolation and acclimation are absolute key factors in moving forward,” he says. “We need to make sure we do this right.”

Misener has had good success with vaccinating sows and then injecting them with Pulmotil to reduce the severity of the vaccine response. The result is a high survival rate of protected sows.

PMWS, which strikes Canadian pigs three to five weeks after they enter the finisher, is costing the province $8.8 million a year due to death losses. When treatment costs and culling losses are added in, the total balloons to an estimated $17.6 million.