OTTAWA -- Ottawa’s top doctor is warning of a worst case scenario for COVID-19 cases in Ottawa if residents don’t continue to practice physical distancing, self-isolate if they’re sick and take steps to help flatten the curve.

Medical Officer of Health Dr. Vera Etches says models suggest if nothing is done to stop the spread of novel coronavirus, Ottawa could see “up to 4,000 cases a day at the peak” of the pandemic.

Ottawa Public Health is investigating 25 confirmed cases and 13 indeterminate cases (awaiting final lab test results) of COVID-19.

“We anticipate this number will continue to increase as more people are exposed to the virus in our community and are getting tested,” said Dr. Etches.

Ontario’s Ministry of Health has reported 27 confirmed cases of novel coronavirus in Ottawa.

The worst case scenario of 4,000 new cases a day in Ottawa is based on modelling data from the University of Toronto that describes COVID-19 transmission, based on a model that was used in 2009 for the H1N1 pandemic planning in Canada.

Ottawa Public Health says the model tries to take into account diagnosed cases, cases that go undetected because they have no symptoms or only mild symptoms, coronavirus infection rates and symptomatic and asymptomatic cases.

When asked by CTV News Ottawa how big of an increase in cases Ottawa could see during the pandemic, Dr. Etches said “we’ve seen models … you could see estimates of up to 4,000 cases a day.”

“That’s a long way from where we are right now, and I hope we don’t reach that. But these are the kinds of things that we’re looking at and trying to understand how we avoid that.”

The Medical Officer of Health says the model data is changing daily, and couldn’t say when Ottawa may see peak transmission of the novel coronavirus in the community.

Ottawa Public Health told CTV News Ottawa after Dr. Etches conference call on Tuesday that the unit releases the estimated number of cases “publicly to help raise awareness that COVID-19 is in our community, and to communicate that we all need to do our part to slow down transmission of infection by limiting our contact with others.”

Ottawa Public Health notes measures have been put in place to help “flatten the curve,” including the closure of schools and non-essential businesses, and physical distancing recommendations.

Dr. Etches told reporters on Sunday that there’s an estimated 4,000 cases of COVID-19 in Ottawa. Etches suggested models showed the number of cases could double every three days.

Ottawa Public Health has launched a social media campaign to practice safe physical distancing and social distancing.

The health unit says social distancing means “avoiding crowds and maintaining a distance of two metres from those around you.”

Safe activities include going for a walk or hike, video chat and watch movies or reading a book at home.

Dr. Etches told reporters on Tuesday that “many residents are heeding the advice to stay home and limit non-essential outings. I’m very grateful people are following public advice.”

“The action that you’re taking will affect not only you, but also your loved ones and our most vulnerable.”