YouTube personality Corey Dixon says his service dog, Aspen, has died at the emergency veterinary office after a stay at a Toronto-area PetSmart hotel but PetSmart says Aspen’s illness was due to a pre-existing condition.

Dixon told Global News on Sunday that his vets informed him his dog died of severe pneumonia but that tests were still pending.

In a statement sent Sunday afternoon, PetSmart said they had contacted the treating vet and the cause of death was a pre-existing issue.

“We are deeply saddened to learn of Aspen’s unfortunate passing,” it read.

“The treating veterinarian reported the cause of death as a pre-existing autoimmune disease called Myasthenia Gravis, an illness completely unrelated to Aspen’s stay at PetSmart. We’ll continue to stay in contact with the pet parent during this difficult time.”

However, Dixon said this has not been confirmed by veterinarians yet. He said blood tests have been sent off but results have not been received.

“That was one of the differentials, but the results haven’t come back. I asked them this morning and they said they hadn’t got the blood work back,” said Dixon. “The reason she was put down was her breathing. She literally stopped breathing this morning because of her pneumonia.”

Dixon said that he had left Aspen in the care of Etobicoke’s PetSmart hotel while he went to a cottage with some friends.

But when he came to pick Aspen up after the week was over on Sunday, he found the dog weak, ill and in need of urgent care.

On Sunday morning, after a week in veterinary care, Dixon said he had to put Aspen down.

“We came in [to the vet] this morning after the vet called and said she wasn’t doing too great. Her fever was back up, she was having difficulty breathing,” Dixon said through tears.

“The vet said we had to come in to talk about our options. So we did and had a lovely talk with the ICU doctors and they recommended we put her down. She was really suffering.”

Dixon said all his family and friends were with him at the emergency vet mourning Aspen together. “I’m never going to forget this dog. She’s saved my life,” he said.

He told reporters on Thursday the emergency vet told him the dog had lost nearly 10 pounds and they were concerned Aspen had an intestinal blockage. Dixon discovered the dog bed Aspen had used during the week had been chewed on and Dixon wondered why PetSmart staff hadn’t removed it from where the lab was sleeping.

PetSmart offers a 24-hour on-call vet as part of its boarding package. It’s not known if staff had a vet look at the dog, but Dixon said they should have recognized his dog needed help.

In a statement to Global News on Thursday, a spokesperson with PetSmart said an investigation was underway. But it said early findings show staff followed the company’s policies and procedures. It said it has also asked for medical records to understand the cause of Aspen’s illness.

READ MORE: Service dog in emergency veterinarian care following stay at PetSmart hotel in Etobicoke

PetSmart refunded Dixon the cost of the boarding fees as well as covering $5,000 of the veterinary costs.

Dixon said a GoFundMe was set up to help cover additional costs and the remainder of it will be going towards a memorial for Aspen who was more than just a dog to him. She was a valued family member.

“We’re very thankful and grateful for all the support we’ve had and all the generous donations to help cover her vet bills,” he said.