The man, in his 30s, is in stable condition at Providence Regional Medical Center in Everett, Wash. Officials said they are monitoring him there out of an abundance of caution, not because he is seriously ill. The man arrived in the United States last week, before federal health officials began screening travelers from the central Chinese city of Wuhan at Los Angeles, San Francisco and New York’s John F. Kennedy international airports, the first such effort since the 2014 Ebola outbreak.