Over the past three years, avian influenza (H5N1) has spread around the U.S. and affected many species of birds and mammals, including humans. Experts at a recent webinar offered answers to common questions about the disease — how it spreads,

Health officials are making a renewed call for vigilance against bird flu, but some experts are puzzling over why reports of new human cases have stopped.

Brazil's Tocantins state said on Wednesday the agriculture ministry has ruled out an outbreak of bird flu on a local commercial farm, citing conclusive test results received from the ministry.

So far, the only people to come down with bird flu got it from animals. Dr. Jon LaPook reports on how research is underway to keep bird flu from mutating into a form that could spread from person to person.

The FDA also approved treprostinil (Yutrepia) inhalation powder for patients with pulmonary arterial hypertension and pulmonary hypertension associated with interstitial lung disease, said Liquidia.

After rebounding in recent decades due to conservation efforts, the number of once-imperiled peregrine falcons in the U.S. has been dropping again in some places due to the bird flu.