Ontario has just announced its biggest one-day increase in the number of 2019 novel coronavirus cases yet.

A total of 17 new cases were confirmed today, one of them in an infant who was in close contact with an existing COVID-19 patient.

The new cases are scattered across the Toronto, Peel, Hamilton, Waterloo, Ottawa, Halton and Simcoe Muskoka regions, and all but four have just returned from international trips to places like Italy, the U.S. and Spain.

The four patients who do not have any recent travel history contracted the communicable disease from close contact with affected individuals.

This is by far the single biggest one-day increase in new #COVID19 cases in Ontario since the #coronavirus arrived in this province in late January.... 17 new cases is a 40% jump in a day. https://t.co/vKu1zn5nKb

— Mike Crawley (@CBCQueensPark) March 12, 2020

The baby was assessed at North York General Hospital, while other patients ranging from their 20s to their 70s were examined at Sunnybrook Health Sciences Centre, St. Michael's Hospital, Trillium Health Partners Mississauga Hospital, and Burlington's Joseph Brant Hospital, among others outside of the GTA.

All are currently in self-isolation at home, and are not presenting with severe enough symptoms to require hospitalization or medical attention.

The provincial total is now at 59 — five of whom have recovered —bringing the Canada-wide tally to 135 at the time of publication: the 59 in Ontario, 46 in B.C., 19 in Alberta, nine in Quebec, one in New Brunswick and one a repatriated Canadian in Trenton, Ontario.

Saskatchewan also just announced its first presumptive positive case this afternoon.