U.S. swine flu case numbers rise, more expected

By Andrew Quinn

WASHINGTON (Reuters) - More than 40 people in five states have been sickened by new strain of swine flu that doctors fear may cause a pandemic, U.S. officials said on Monday, promising more cases to come.

Schools were ordered closed in California and Texas, while nervous investors sent U.S. stock prices tumbling on expectations that the flu outbreak could further undermine the economy, which is struggling in recession.

President Barack Obama said he was monitoring the situation while bad news piled up from southern neighbor Mexico, where up to 149 people have died and more than 1,600 have been infected by the never-before-seen virus.

The U.S. government on Sunday declared the flu strain a public health emergency -- a fresh challenge for the Obama administration, which is still mindful of the damage inflicted on his predecessor George W. Bush over his government's inept handling of Hurricane Katrina in 2005.

No American deaths have been reported and most affected by the virus had light symptoms, recovering fast. But it has popped up in New York, Ohio, Kansas, Texas and California as well as Canada and Europe, raising fears of a pandemic.

"This is obviously a cause for concern and requires a heightened state of alert. But it is not a cause for alarm," Obama told a meeting of the National Academy of Sciences.

In New York City, Mayor Michael Bloomberg said more than 100 sick students at a high school in Queens were being tested and that 45 were confirmed or likely cases of swine flu.

"We believe that there are probably more than 100 cases of swine flu at the school and lab tests are confirming what we have suspected," he told a news conference.