The bird flu virus hasn't yet spread from person to person, the CDC said Thursday, releasing findings from a monthslong probe into a hospitalized Missouri patient.

Flies buzzed around a pile of about a dozen dead cows on a California dairy farm.  An industry representative and state officials confirmed the scene of dead cattle was filmed outside a farm where there had been an outbreak of the virus.

US health officials didn’t find signs of human-to-human bird flu spread after testing a group of people in Missouri with suspicious symptoms.

Four agricultural workers in Washington state were recently diagnosed with avian influenza A (H5N1). The cases mark the first human infections of the disease under investigation in the state.