The US Centers for Disease Control and Prevention is urging hospitals to accelerate advanced testing of people they suspect may have 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 CDC is calling for expanded testing of bird flu after a child in California tested positive for the virus despite no known contact with animals.

The Centers for Disease Control and Prevention today released an advisory recommending clinicians expedite subtyping of type A influenza samples from hospitalized patients, particularly individuals in an intensive care unit.

Doctors should use infection control measures if a hospitalized patient has suspected, probable, or confirmed H5N1, putting the patient in an airborne infection isolation room with negative pressure, and using standard, contact, and airborne precautions with eye protection such as goggles or a face shield.

CDC officials say they extended the guidance now because they are seeing more H5N1 patients whose illness they cannot track back to an infected bird or cow.

A child ill with fever and conjunctivitis in San Francisco tested positive for bird flu but had no known source of transmission.