Amid rising respiratory illnesses, a CDC report reveals undetected bird flu cases in US veterinarians. The spread, shown through antibody tests, indicates infections occurring beyond known zones. Experimental confirmation of H5N1 transmission through cow milk prompts officials to urge all states to join the national milk testing program.

The current human case count of H5N1 influenza in the US could be an underestimate, according to a new study from the Centers for Disease Control and Prevention (CDC). After testing 150 veterinarians,

A CDC study has found H5N1 bird flu antibodies in veterinarians who had no symptoms and no knowledge they had been working with infected livestock.