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 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.

Although it says the risk of bird flu contagion to the public remains low, with no evidence of human-to-human transmission, the Centers for Disease Control and Prevention is calling on hospitals to test flu