CDC: a third of US flu cases visited Mexico

Health officials say about one-third of the confirmed U.S. cases of swine flu are people who had been to Mexico.

That suggests a substantial portion of the U.S. cases may have picked up the infection in Mexico. But the Centers for Disease Control and Prevention said Saturday that many people are getting the illness here. And the flu virus is probably still spreading.

CDC officials say the agency knows of confirmed cases from 21 states. Connecticut, Florida and Missouri are the latest to join the list.

The CDC official count now stands at 160 confirmed cases. But that total may already be outdated because some states can now do their own tests for the swine flu virus and don't have to send samples to the CDC.