Seasonal flu, or influenza, is a virus that infects the upper respiratory tract of humans and most animals, including swine.
Speaking to Farmscape, Dr Susan Detmer, an Associate Professor in the Department of Veterinary Pathology with the Western College of Veterinary Medicine, says flu samples from pig barns typically start to trickle in in the fall around the end of September but normally they don't start to peak until mid-October.
"That's when we get the colder weather. Every time we get a cold snap, we tend to see more influenza.
"Just this last week we had temperature changes from plus four down to minus 20. When you have that kind of drastic change, that's when the vents are all closed. They turn down the amount of air circulation to keep it warmer in these rooms where the baby pigs are hanging out and, with that lower air flow, they tend to get more influenza that's already there," Dr Detmer explains.
"Also, with the cold snap, it gives them that added stress.
"When the temperature fluctuates in the rooms where the pigs are, that adds stress so it's an environmental stress.
"It was cold, then it was warm, then it was cold and then it was warm again over the last month.
"That's why we saw this huge surge in samples that I was receiving starting around September 23rd and then it slowed back down around the 10th of October.
"I've already received some emails so I'm expecting an uptick in samples that I'll be receiving over the next week."
Dr Detmer says, if you work with pigs, get vaccinated and if you don't get vaccinated, or even if you do, don't go onto a farm if you have a fever because those pigs are highly susceptible.