40 Swine Flu Cases Now Reported in U.S.

April 28 -- MONDAY, April 27 (HealthDay News) -- The number of confirmed cases of swine flu in the United States has doubled to 40, with all the new cases coming from a New York City high school that had previously reported eight cases of the infectious disease, U.S. health officials said Monday.

The officials also said they were tightening their travel advisory to Mexico -- believed to be the source of the outbreak that continues to reach around the world -- recommending that all nonessential travel to that country be avoided.

And late Monday, the BBC reported that the World Health Organization raised the alert level over swine flu from 3 to 4, two levels shy of declaring a pandemic.

"This situation is evolving very quickly, it is changing quickly," Dr. Richard Besser, acting director of the U.S. Centers for Disease Control and Prevention, said during an afternoon teleconference. "We are officially reporting 40 confirmed cases in the United States. The only change from yesterday is 20 confirmed cases in New York City. These are associated with the same school outbreak and really represent additional testing in that group and not an ongoing spread."

All 40 U.S. patients -- 28 in New York, seven in California, two in Texas, two in Kansas and one in Ohio -- have either recovered or had mild infections, Besser said.

"Later today, we will be releasing a new travel advisory for Mexico," he added. "This is out of an abundance of caution, and we will be recommending that nonessential travel to Mexico be avoided."

Mexico is reporting as many as 1,900 possible swine flu infections and as many as 149 deaths.

Earlier Monday, President Barack Obama said the threat posed by the swine flu outbreak was a cause for concern but "not a cause for alarm."

"The Department of Health and Human Services has declared a public health emergency as a precautionary tool to ensure that we have the resources we need at our disposal to respond quickly and effectively," Obama told a gathering of scientists at the National Academy of Sciences, amid increasing worries worldwide about a possible pandemic, the Associated Press reported.

Besser said that he "expects that we will see [swine flu] cases in other parts of the country, and I would fully expect that we will see a broader range in terms of the severity of infection. Thankfully, so far we have not seen severe disease in this country as has been reported in Mexico."