Bird flu outbreaks among dairy cows in multiple states, and at least one infection in a farmworker in Texas, have incited fears that the virus may be the next infectious threat to people.

The influenza virus, called H5N1, is highly pathogenic, meaning it has the ability to cause severe disease and death. But while its spread among cows was unexpected, people can catch the virus only from close contact with infected animals, not from one another, federal officials said.

"It’s really about folks who are in environments where they may be interacting with cattle that are infected with this virus,” said Dr. Demeter Daskalakis, the director of the National Center for Immunization and Respiratory Diseases at the Centers for Disease Control and Prevention.