Officials say they've found the source of a measles outbreak in Washington State.
The Patient Zero came from outside the country and came into contact with a large group of unvaccinated children, according to State Epidemiologist Scott Lindquist . Those kids then spread out into public places like a Costco and a Portland Trailblazers game.
There are 50 confirmed cases in Washington State, mostly children and most of them in the Vancouver area. Health officials are closely monitoring another 100 possible cases.