Health officials across the globe are closely monitoring the rapid spread of bird flu.
While cases among humans remain rare, the virus is increasingly being found on poultry and cattle farms.
California Gov. Gavin Newsom declared a state of emergency Wednesday over bird flu infection in cattle herds in the state.
Dr. William Schaffner told Scripps News that the bird flu has been around for 20 years and, so far, it has not evolved into the kind of virus that is spread from person to person.
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"I think everyone in infectious diseases and public health around the world is looking at this very, very carefully. Could this bird flu virus develop the genetic capacity to be transmitted readily from person to person? Because that would be the opening door to a new major pandemic," Schaffner.
To date, there have been 61 confirmed human cases of bird flu in the U.S., but no human-to-human transmission.
Most of the cases have resulted in mild symptoms for patients in the U.S. and a full recovery. However, the Centers for Disease Control and Prevention said on Wednesday that a person in Louisiana is the first to be hospitalized with a severe case of bird flu, and also the first to be infected from exposure to sick birds in a residential setting.
