Rat infestations across Northern Ireland have surged to unprecedented levels, as pest controllers report the highest number of callouts for vermin-infested households in a decade.
A combination of heavy rainfall and increased building work have triggered an explosion in rodent numbers, with one pest control company revealing the number of callouts over the past month has been the highest in 10 years.
Trevor Hayden, who runs all-Ireland company Complete Pest Control, said his resources have been stretched to the limit, with rat-related jobs increasing by 150% from the same period last year.
He said: "It's gone crazy out there with rats. This company is now 10 years old, and this has been the busiest start to the winter I've ever known.
"I partly put it down to the weather. The winters are milder, which means they have a higher survival rate over the season. But we've also had a lot of rain lately, which forces rats above ground.
"On top of that, there's definitely more building work going on around the country, which again disturbs rats and leads them to start looking for somewhere else to live. That's why so many seem to be getting into people's houses.
"I'd estimate that we've been getting about 40 calls a day for rat problems since late October, which is more than we've ever had, and a massive amount for a company our size. Most of our jobs are in the cities, like Belfast and Dublin.
"If the weather starts to get colder as we head into December, it could potentially become even more of a problem because there'll be more rats looking for shelter in people's homes."
Although exterminators have mostly had to tackle homes with just one or two rodents, pest controllers have warned that rats can multiply quickly in numbers.
And they have warned families with small children to be on their guard, as they can be vulnerable to potentially-fatal Weils disease, which spreads when vermin-carrying rodents urinate on something which is then accidentally ingested by humans.
"The problem with Weil's disease is that symptoms are very similar to flu, so people are not likely to realise they have it or may be reluctant to visit the doctor," said Mr Hayden.
"But having said that, the chances of catching it are very slim, because as soon as the rat urinates the bacteria starts to break down.
"And someone would have to ingest what they've urinated on almost immediately. But it does mean that toddlers and small children are most at risk if there are rats in a family home."
Whilst rats are accounting for up to four in five jobs for pest control experts, the other major seasonal pest at this time of year has been mice.
"It's very difficult to completely proof a building from mice. They are small and can squeeze through the tiniest of holes. But they can be a problem from a hygiene point of view, and need to be dealt with," said Mr Hayden.
"It's the time of year when people head up to their attics to bring down the Christmas decorations.
"My advice to people would be to take the time to check their attics for droppings.
"If you spot droppings from either rats or mice on top of the insulation, then you have a serious problem."