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.

Centers for Disease Control and Prevention officials told reporters Thursday that there is no evidence that there has been any case of human-to-human spread of H5N1 bird flu in the mysterious situation reported last month in which several people in Missouri suffered illnesses unrelated to known animal contact.

Federal health officials announced Thursday that a Missouri resident infected with bird flu did not spread the virus to others, alleviating concerns about potential human-to-human transmission during the current nationwide outbreak affecting poultry and dairy farms.