H5N1 usually spreads to people through contact with infected or dead birds, as with the Louisiana patient. Currently, there are no known cases of human-to-human transmission, said the CDC's Dr. Demetre Daskalakis.

There have been reports of bird flu cases throughout the U.S. and one confirmed case in Louisiana. Here's what the CDC says about bird flu infections.

A genetic analysis of viral samples from a patient in Louisiana hospitalized with the first severe case of bird flu showed mutations that may result in the virus becoming more transmissible