TORONTO -- As COVID-19 spreads through Canada and infects hundreds of people, the widow of a 51-year-old Ontario man who died of the disease is urging Canadians to listen to health officials to prevent the spread of the virus and whenever possible stay at home.

“I think that people aren’t taking this seriously enough,” Teri Cunnington told CTV News from her home in Milton, Ont.

Sean Cunnington, a salesman, musician and father of three from Milton, Ont., developed flu-like symptoms on March 4 and began experiencing night sweats. Shortly afterward, he developed a cough.

Sean had a form of chronic leukemia, but was otherwise healthy and physically active. He did not rely on any medication.

After two days of struggling at home, Sean was urged by his wife to visit the hospital. He was not tested for COVID-19 because he did not fit the criteria at the time, which specified foreign travel to any country with COVID-19 cases as a risk factor.

“It was basically dismissed because he had not travelled anywhere. He’s not been out of Ontario, he’s not really been out of southern Ontario,” Teri said.

Sean was prescribed antibiotics and sent home, but his condition only got worse. Five days after being sent home, Sean was admitted to hospital in Milton where doctors suspected he might have COVID-19 and tested him.

While doctors awaited the formal results, Sean was moved into an isolated negative pressure room, where he was put on oxygen. Teri says healthcare workers were taking full precautions for COVID-19, wearing gloves and masks.

“He just could not breathe. He could not get a deep breath. Before he was intubated he was taking these very short, little breaths and trying to get a big breath, and that was while being on oxygen,” Teri said.

As he struggled to breathe, he was put on a ventilator, but even a maximum flow of oxygen made little difference.

“They had to keep turning the amount of oxygen that Sean was getting from the ventilator … and then they couldn't turn the machine up anymore,” she said.

In one of their final conversations in the hospital, Sean -- whose lungs were failing due to the disease -- told his wife that he didn’t want to die.

“I think he was really scared and I guess obviously he was scared enough that that’s what he said to me,” she said.

She replied: “Don’t die, our story’s not over yet.”

Sean passed away Wednesday night in hospital. Ten hours after his death, doctors finally received the results of his COVID-19 test. He tested positive.

Officials do not know where he contracted the illness, a sign the illness is spreading within communities.

Sean leaves behind three daughters. He worked in sales and, outside of his job, his passion was music. His band, Elmwood Underground, released their first single in late February.

“He was the most caring, most loving genuine person. He was my everything,” Teri said.

Teri cannot visit the funeral home to plan her husband’s memorial service because she is now in self-isolation until March 25. So far, she said she feels fine. Even if she could plan the arrangements, she said there’s no way she could hold a funeral right now, considering the limits on crowds.

“Sean has an incredible number of people who care about him and love him, and he has touched so many people,” she said.

Teri said Sean’s co-workers have been in touch with public health, and her own workplace has been cleared out as a precaution.

Teri’s final message is a simple one: listen to the experts and stay indoors.

“And everybody just needs to be safe out there. Everybody just needs to be mindful of what they’re doing. Stay home, stay home -- it’s not such a big deal.”

As of Thursday night, 12 Canadians have died of COVID-19 and more than 870 others have been infected.

One of the things she’ll miss the most about her husband, Teri said, is the way he would call “Marco!” when he was trying to find her at home. She would reply, “Polo!”

“So, I won’t have that anymore,” she said. “There are no words. There really are no words. This is something that nobody should ever have to experience.”