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.

The US Centers for Disease Control and Prevention is urging hospitals to accelerate advanced testing of people they suspect may have bird flu.