Canadian Premier Justin Trudeau announced at a press conference yesterday that Canada's borders will immediately be closed to all non-citizens (except Americans "for the moment" because of the "level of integration of our two economies").

Trudeau's wife has tested positive for COVID-19.

More than a million people move through US-Canada borders daily by ground, air and sea.

Any closure of Canada's borders to US citizens would do very serious damage to Canada's tourism industry.

Other exceptions to the closure to be announced later may include air crews, diplomats, and immediate family members of Canadian citizens.