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.

A group that advocates for animal rights says the US Government needs to do more to stop the spread of bird flu or H5N1. More than 100 million birds have been affected according to the CDC and over 1 million birds have been euthanized in the United States due to bird flu.

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.