(Vancouver, WA)  --  Officials say they've found the source of a measles outbreak in Washington State.  The so-called 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.