Bird flu may be spreading between people and cats more than previously thought, a new federal study said. The findings published Thursday by the Centers for Disease Control and Prevention’s weekly journal add to worries about the spread of highly pathogenic avian influenza from people to cats and vice versa.

The highly contagious H5N1 bird flu virus may be spreading through the air under certain conditions, according to a new study from the Czech Republic. Government veterinarians made the discovery while investigating a mysterious outbreak at a highly secured chicken farm last February.