Manitoba hog producers are making steady progress toward eliminating porcine epidemic diarrhea virus from 80 infected premises.
Dr. Glen Duizer of the province’s chief veterinary office said 24 of those 80 are now presumed to have eliminated the virus and another 24 are in the transitional phase and should be deemed free of the virus shortly.
“We are happy to have progressed that far. We have pretty good expectation that over the next four to five weeks we’ll have a significant number that will move on also from through transition to presumptive negative,” Duizer said Dec. 13 during a conference call organized by Alberta Pork.
Manitoba has not had a new case of PED since Oct. 24, and Duizer said the province is well down the road to becoming PED free.
The virus was concentrated in southeastern Manitoba and involved 25 sow herds, 16 nurseries and 39 finisher operations. It required surveillance of about 77,000 sows and more than one million other pigs.
Though Duizer said the industry is pleased with eradication efforts, producers are concerned about potential outbreaks in April, May and June, the period in which the virus has struck in the past.
“I would say that we have seen significant changes in how farms are approaching the upcoming season. We are seeing them or hearing of producers that are ready to implement high end biosecurity factors,” Duizer said.
As well, the industry has developed dedicated transport lines for shipping cull animals and made changes to the cleaning and disinfection procedure on transport trucks.
Since many hogs are shipped to the United States, where PED is endemic, viral spread via transport truck remains a risk.
Duizer said producers are also being advised to limit the number of staff they share with other operations, which is another possible route of virus transmission.
Of the 80 infected farms, 30 were infected as a direct result of animal movement from one level to the next. In 18 of those cases, movement of pigs occurred before clinical signs of PED were found in the barn where the pigs originated.
“These were farms that because of space requirements and the need to find places for finishing pigs, these were farms that were in the high risk buffer areas but were negative … but were close to other positive farms and they were needed to receive pigs.”
Duizer said it appears that previously infected pigs can become low-level shedders of the virus later on, in some cases four to eight weeks after they have recovered.
“The pigs need to be considered a risk for their entire lives until they finish out, and that’s certainly the approach that we are taking now.”
That indicates immunity does not last as long as previously believed.
There is concern that manure from infected premises is a threat for infection after it is spread on farmland. Duizer said that risk is reduced by dedicating equipment for manure spreading from infected premises. He said areas where this manure has been spread have been mapped and are typically close to infected farms.
“Our current understanding of the virus would suggest strongly that … if (manure) is a risk, it’s likely because it’s tracked on the equipment and less so because it’s tracked from the field after it’s spread.”
Pigs killed by the virus were either deeply buried in landfills or on-site at the infected farms, said Duizer. Efforts were made to keep highly positive animals out of the rendering process to limit risk of crossover contamination from rendering facilities. However, he said the rendering process itself does kill the virus.
Dr. Julia Keenliside, a veterinary epidemiologist with Alberta Agriculture, said Alberta remains free of PED, as is British Columbia and Saskatchewan.
Her department tests more than 280 samples each month from slaughter plants, assembly yards, trucks and truck washes.
Keenliside said Ontario, like Manitoba, is making strides in PED eradication. Ontario has had 105 cases, the most recent of which was confirmed Nov. 23, according to Ontario Pork.
“They are very close to eliminating the virus, which is very good news. It will be quite something to see them successfully eliminate it from the province, and I’m not aware of too many other regions in the world that have been able to do that,” said Keenliside.
PED virus is contagious and is almost always fatal to young piglets. Older animals can survive, but it does affect production. The virus is not a risk to people.