Germany reported an outbreak of highly pathogenic H5N1 bird flu on a farm in the eastern region of Saxony near the border with the Czech Republic, the World Organisation for Animal Health (WOAH) said on Monday.

In what could be the first cases of bird flu spreading between humans in the United States, a group of potential H5N1 infections in Missouri has now grown to eight.

Dhillon is an instructor in the Division of Global Health Equity at Brigham and Women’s Hospital and Harvard Medical School. Karan is an infectious disease physician and epidemiologist at Stanford University. Srikrishna is founder of Patient Knowhow.

None of the health care workers or other contact have tested positive for avian flu antibodies so far — but could their illness signal human-to-human transmission?

Seven people in contact with a patient hospitalized with bird flu also developed symptoms, the C.D.C. reported. Some are undergoing further tests.

The CDC said an investigation into a human H5N1 bird flu infection in Missouri has found four additional health care workers who fell ill after caring for the patient.

At least one household member and six healthcare workers who encountered the index case-patient are being investigated after showing symptoms of viral infection.

In what could be the first cases of bird flu spreading between humans in the United States, a group of potential H5N1 infections in Missouri has now grown to eight. However, state health officials are still awaiting antibody tests to confirm whether the H5N1 infection is growing,