MONTREAL -- It’s the stuff of nightmares.

Exterminators have seen more calls lately about rat and mice infestations. And while some are for homes, they're getting more calls to office towers as well -- because, with humans home, they're being taken over.

“What we’re seeing is these buildings are more or less vacant or virtually empty, so that’s allowing rodents like mice and rats to have a run of the entire place,” said Bill Dowd, the owner of Skedaddle Humane Wildlife Control.

Business is booming, he said. Calls and revenues have jumped about 30 per cent since the pandemic began. 

Dowd said rats are normally shy critters, but with workers gone from many offices, those spaces can be appealing places to colonize.

That's a problem for a few reasons. Rats can cause a lot of damage such as chewing through electrical wiring and support joists, and even causing fires.

They’re also concerning from a health standpoint. 

“Some of our work has found that Interacting with rats in our homes or in a business can have negative mental health impacts on people,” said Kaylee Byers, a post-doctoral fellow at the University of British Columbia’s School of Population and Public Health.

“Rats also carry a number of bacteria that can make people sick. When we think about rats we often think about the plague, but there are many other things rats can carry.”

Exactly what pathogens the rodents carry varies between cities and even neighbourhoods. Byers said that part of the challenge in keeping down rat populations in urban centres is that they’re incredibly adaptable.

“They’re in cities all over the world, so they can adapt to lots of different environments, they can survive on lots of different types of food sources … which has allowed them to do really well,” she said.

CRAFTY CRITTERS

So how are they getting inside? According to Dowd, it’s actually pretty easy for rodents to gain access to a building.

All a mouse needs is an opening the size of a dime, and he says that a rat can squeeze its body through an opening the size of a quarter. Sometimes they’ll get in through the pipes.

“Rodents do travel our sewer systems,” he said.

“In older commercial properties and even residential for that matter, there may be an old sewer pipe that’s coming in from the street into the building, and over the years people do renovations and modifications and they cut that plumbing pipe, but that opening is still open from the street into the basement or into the structure.”

He says that occasionally, rats come up through the toilet – and not only rats, but even squirrels and snakes.

In commercial buildings that aren’t in use, the water is sometimes drained from the toilets, giving rats easy access from sewers. But Dowd said even when the water is still there, it doesn't deter these agile critters, because they’re excellent swimmers.

National Geographic posted a video in 2015 that showed a rat easily navigating a toilet’s plumbing. 

IT’S NEVER A PARTY OF ONE

While one or two rats or mice in your building might seem like a manageable problem, if you see them, what you’re likely dealing with is a full-on infestation.

“For every one mouse, or one rat you see, typically there’s anywhere from 20 to 30 others,” said Dowd. “Usually when you see one, it’s already too late -- you have an infestation there.”

Both rats and mice are prolific breeders.

“They reproduce every 21 days and then those new babies can reproduce in 21 days, so the numbers go up exponentially, and very quickly," he said.

HOME INVASIONS

Dowd says his company is also getting more calls for rodent infestations in residential properties, likely for the opposite reason -- because people are spending more time at home.

“People are working from home, so they’re more in tune and they’re hearing that rat or mouse, rat, racoon or squirrel in their walls, and they’re acting immediately to save their biggest investment of their life, their home,” he said.

Dowd says property owners should be checking their buildings on a regular basis, and they should contact a pest control professional if they see or hear evidence that rats or other rodents might be inside the building.

When the problem has been ignored for a long time, he said, it's obvious. In the worst experiences, his workers have lifted up ceiling panels and rodent feces have rained down on them.

Dowd may be swamped with calls already, but he believes it’s just the beginning of what he’s going to see in offices, whenever, one day, this is over.

“I’m anticipating when we all get back to our normal life after the pandemic," he said, "that we’re going to get inundated with calls.“