Blood tests of several people who were in contact with a patient in Missouri who caught H5N1 bird flu without any known exposure to infected animals reveal at least one of them — a person who lived in the same house and had symptoms at the same time — also had the virus,

A second person in Missouri who wasn't exposed to either poultry or dairy cows has been infected with bird flu, U.S. health officials reported Thursday.

Even as cases of H5N1 virus among animals and people are rising in the U.S., there’s no evidence of human-to-human transmission.

The number of people infected with bird flu in the U.S. has risen to at least 31, federal health officials said Thursday, but there is no evidence of human-to-human spread after blood tests

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.

New test results suggest Missouri did not see a cluster of bird flu cases, a possibility that some experts had feared.

The agency tested blood from health workers who had been exposed to a person with H5N1 bird flu and later developed flu-like symptoms, raising concerns of human transmission.

The number of workers at a Franklin County commercial egg farm who have now tested positive for avian influenza has increased to eight, according to preliminary test results.