The CDC advises testing hospitalized flu patients for bird flu within 24 hours to prevent delays in identifying human infections. While the public risk remains low, nearly 70 Americans have contracted bird flu.

People hospitalized for flu should be tested for bird flu within 24 hours, the U.S. Centers for Disease Control and Prevention said on Thursday, in an expansion of the agency's efforts to tackle increasing infections in humans.

The agency is advising enhanced safety measures in Minnesota and South Dakota, where turkey flocks with more than 500 birds should be isolated, monitored and tested for bird flu within 72 hours before going to slaughter,