An image of a man is seen on the display of a thermal camera, set up to screen outgoing passengers as a precaution against the spread of swine flu, at the international airport in Mexico City, Wednesday, June 10, 2009. The World Health Organization is gearing up to declare a swine flu pandemic, a move that could trigger both the large-scale production of vaccines and questions about why the step was delayed for weeks as the virus continued to spread. (AP Photo/Gregory Bull)
Gregory Bull / The Associated Press