New flu continues U.S. spread, but people cleaner

By Maggie Fox, Health and Science Editor

WASHINGTON (Reuters) - The new H1N1 influenza virus quickened its spread across the United States, but health officials said on Friday they were encouraged that more people were washing their hands as a result of the outbreak.

States reported 2,500 probable and confirmed cases of the swine flu, acting Centers for Disease Control and Prevention director Dr. Richard Besser told reporters.

"There are 1,639 confirmed cases in 42 states and the District of Columbia," Besser said. About 3.5 percent of cases have been sick enough to be admitted to hospitals and health officials say the rate will continue to fall as more screening is done in the community, as opposed to looking at the sickest cases.

The CDC may begin to re-think its strategy on testing suspected cases as it becomes clear the H1N1 swine flu virus is established in various communities, Besser said.

"At some point we are going to reach a point where there are too many samples for states to test," Besser said. CDC labs, he said, were testing 300 to 400 samples a day from people with the symptoms of swine flu, such as high fever, dry cough and muscle aches and a quick positive test for influenza.

Of 26 people hospitalized, more than half had an underlying condition known to worsen the effects of flu, including seven with asthma, Besser said.

The good news is the publicity surrounding the outbreaks has made people change their behavior, Besser said.

Dr. Robert Blendon and colleagues at the Harvard School of Public Health surveyed 1,000 U.S. adults, including people who only have cellphones -- a first for a major public health survey.