The CDC reported more than double the cases of norovirus, commonly known as stomach flu, compared to previous years in early December.

In a positive finding, the CDC emphasized that there is no evidence the virus has spread from the Louisiana patient to others, and the mutations alone are unlikely to spread from person to person. CDC scientists also confirmed, however, that the Louisiana virus samples are closely related to candidate vaccine strains already developed for bird flu.

The CDC previously confirmed the first severe human case of bird flu in Louisiana, but now the CDC has confirmed a virus mutation. Find out more here