TLDR: A research by Uni Toronto suggests that the coronavirus epidemic started one month earlier than is commonly reported (Nov 2019) and has yet to be brought under control.
David Fisman, one of the model’s creators said: “You can’t get up to that level of cases if the epidemic started in December. even if you pushed the reproduction really high. The plausible start date seems to be mid-November,”
Wikipedia lists[1] start date to be Dec 1, 2019 and with Fever, cough, shortness of breath etc as symptoms[2], I think it's difficult to predict even for doctors exact date of the outbreak.
[1] https://en.wikipedia.org/wiki/2019%E2%80%9320_Wuhan_coronavi...