2,000 people In Mexico Hospitalized With Serious Pneumonia...

WASHINGTON -- U.S. officials advised Americans against most travel to Mexico on Monday as a swine flu virus that began there spread to the U.S. and beyond. With 40 cases now reported in the U.S., President Barack Obama urged calm, saying there was reason for concern but not yet "a cause for alarm."

Dr. Richard Besser, acting director of the Centers for Disease Control and Prevention, said that so far the disease in the U.S. seems less severe than the outbreak in Mexico, where more than 1,600 cases have been reported and where the suspected death toll has climbed to 149. No deaths have been reported in the U.S, and only one hospitalization.

"I wouldn't be overly reassured by that," Dr. Besser told reporters at CDC's headquarters in Atlanta. He raised the possibility of more severe cases -- and deaths -- in the U.S.

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