The bird flu virus hasn’t yet spread from person to person, the Centers for Disease Control and Prevention said Thursday, releasing findings from a monthslong probe into a patient in Missouri who was hospitalized with H5N1 . The patient, who tested positive for bird flu in August, had no known contact with dairy cows or poultry. H5N1, or bird flu, has been spreading among farm animals, wild birds and other animals and has infected 31 people, mostly farmworkers, in the U.

S. After the Missouri patient fell ill, several close contacts reported respiratory symptoms and health officials conducted serologic, or blood, tests to determine if the virus had spread among them . Test results on five health care workers who became ill after caring for the patient came back negative for any sign of the virus, Dr.

Demetre Daskalakis, who heads the CDC’s National Center for Immunization and Respiratory Diseases, said during a media briefing. “From the perspective of where we are with this investigation, I think we’ve got the conclusion,” Daskalakis said. One blood test on a household member of the patient who became ill suggested the person did have H5 antibodies.

A second test was unable to confirm the finding. An additional look at the cases gave investigators confidence that the patient did not make the household contact sick. It appears that the two people became sick at the same time from the same source — likely some kind of animal or animal product, the CDC said.

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