With the approach of fall and cooler weather across the United States, officials say the risk posed by the H5N1 bird flu virus could rise — and they’re taking steps to prevent the creation of a hybrid flu virus that could more easily infect humans.

Centers for Disease Control and Prevention officials said the risk to the general public remains low. The Missouri case raised questions about the possibility of human-to-human bird flu transmission,

Epidemiologists have not yet identified exactly how a person in Missouri contracted bird flu last week, said the U.S. Centers for Disease Control and Prevention on Thursday. The human case was the 14th diagnosed in the U.