Alberta’s ‘rat-free’ status is in jeopardy, after a rat colony was discovered in the Medicine Hat landfill last week.

Since the 1950s, Alberta has boasted about being rat-free, as an aggressive rat control program kept the vermin outside of the borders.

Exterminators have killed dozens rats in and around the Medicine Hat city landfill since Wednesday.

Minister of Agriculture Verlyn Olson says the province is taking the sighting seriously and will help local crews with exterminating any other rats.

'Rats don't respect provincial borders. But the key is as soon as we find evidence we act very quickly and very aggressively.'— Verlyn Olson, Minister of Agriculture

“This is certainly not the first time a rat has been spotted in Alberta, and it won't be the last time,” says Olson.

“It would be naive to think that no rat ever set foot in Alberta. Rats don't respect provincial borders. But the key is as soon as we find evidence we act very quickly and very aggressively."

It's estimated one pair of reproducing rats could lead to a colony of 15,000 rats in a year, says Olson.

A man with 30 years in the extermination business says Alberta is right to be aggressive about catching rats.

Steve Nelson has been fighting rats in New York City for decades.

“This should be taken seriously. Rats don't carry rabies but they do carry other types of viruses and disease.”

Nelson says it may be unrealistic to completely get rid out of the rats unless the people in Medicine Hat can figure out where the animals came from.

“You would have a baiting situation going on and that situation would be going on until the problem is alleviated. It's possible that it might not be alleviated. It's possible it might continue for quite some time because there's a source. Why did this start now and it wasn't happening in that facility before.”