A Louisiana patient is critically ill with severe respiratory symptoms from H5N1 bird flu, marking the 61st U.S. human case this year. California has declared a state of emergency. CBS News medical contributor Dr.

The U.S. Centers for Disease Control and Prevention says a patient has been hospitalized with a severe case of H5N1 infection in Louisiana, making it the first instance of a severe illness linked to the virus in the United States.

According to the CDC, symptoms of Bird Flu include eye redness, upper respiratory symptoms, pneumonia that requires hospitalization, a fever of 100ºF or higher, a cough, sore throat, runny nose, muscle and/or body aches, headaches, fatigue and/or difficulty breathing. The CDC also notes that having a fever is not always present.