BARRIE -- There are now 503 confirmed cases of COVID-19 in Ontario, including a woman in her 60s from New Tecumseth.

"[She] returned from travelling overseas to Israel, Jordan and Egypt over a week ago and then developed symptoms," confirms Simcoe Muskoka District Health Unit Medical Officer of Health Dr. Charles Gardner.

The woman is Simcoe-Muskoka's 10th confirmed case. She was seen at Headwaters Health Care Centre in Orangeville on Saturday and is said to be in self-isolation.

The latest information comes from the province's daily updated list of confirmed cases, which added 78 new cases Monday morning.

This is the largest single-day spike in cases to date in Ontario.

The list also includes eight new cases from York Region. According to the province, seven of those individuals are self-isolating while a woman in her 50s who recently travelled to the U.S. is in the hospital.

Dr. Gardner warns there is evidence of community spread right across the region. "I think it's important that people everywhere in the province assume it's coming," adding, "if you havent' seen it yet, it's coming."

To date, six people have died, and eight cases have been resolved.

Dr. Gardner says everyone should be practicing self-isolation and social distancing or the number of cases will continue to rise.