(NBC News) – Health officials theorize it could be a “one-off” case, in which the infection wasn’t passed along to anyone else.

The Centers for Disease Control and Prevention said Thursday it has yet to identify “a clear source” of infection in a Missouri patient who tested positive for the bird flu virus despite no known contact with poultry or dairy cows. The CDC disclosed the case last Friday, stating that the patient had been hospitalized on Aug. 22 and has since recovered. (Read More)