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.

Bird flu may be spreading undetected in humans, according to a recently released report from the Centers for Disease Control and Prevention Data posted last week in the CDC’s Morbidity and Mortality Weekly Report suggests the spread of bird flu between dairy cattle and humans has gone unchecked,