A security guard looks out from the National Institute of Respiratory Diseases, where people complaining of flu-like symptoms were being isolated, in Mexico City on Monday, April 27, 2009. International fears of a pandemic rose Monday as the number of people killed by the swine flu in Mexico climbed to 149. Signs from top read: "There will be no new appointments until further notice;" "Please keep the door closed;" and "We recommend patience." (Adriana Zehbrauskas/The New York Times)