KITCHENER -- A family who had to put down their five-month-old puppy because of a health issue is warning others to do research before their purchase.

They bought the dog from a farm in Waterloo Region. His health quickly deteriorated after he came home and he was diagnosed with a rare terminal illness.

"We looked at some breeders, but they were looking at late 2021, and we were kind of hoping to have a Christmas present for the boys," Maria said,

Maria and her family, who asked their last name be kept private, turned to a local farm.

"We felt like it was a nice family farm that was just breeding puppies," she said.

Maria said there were no red flags at the farm, but she quickly noticed changes in their new puppy's behaviour.

"We noticed that he walked a little bit strange," she said. "Some people said it was just because he was a puppy and he hopping, but we noticed that that didn't seem to go away."

After multiple trips to the vet and thousands of dollars, the puppy was diagnosed with muscular dystrophy, which is a terminal illness in dogs.

"Having to tell a six- and 15-year-old that had fallen head-over-heels in love with him that we were going to take him to the vet to put him down was just heartbreaking," Maria said.

She said they're worried there may be more sick puppies out there.

"We were told from the neurologist that every male pup that this one dog has and had will have the disease, because they carry that gene," Maria said.

Kathrin Delutis, the executive director of the Humane Society of Kitchener Waterloo and Stratford Perth, said there are important questions that should be asked before bringing a puppy home.

"How often has the mom been bred? How many litters have you actually had? At what point do you return this pet?" Delutis said.

"It is worth waiting and doing it the right way," Maria said. "Had we done a little bit more research, we could have avoided all of this."

Delutis said puppy sale scams have been on the rise during the pandemic.

"Unfortunately Waterloo Region isn't exempt from the scams that are going on," she said. "We've been made aware of different situations taking place that the police have been investigating."

"I just want everybody to really do their research first," Maria said. "I don't want to see any more puppies or families go through what we did. It's very painful."

The Ministry of the Solicitor General said Animal Welfare Services is investigating the matter, but wasn't able to provide any further details.