What to Know About the Bird Flu Outbreak in Dairy Cows

An unusual bird flu outbreak in dairy cows has now affected at least 13 herds in six states, according to federal and state officials. These infections represent the first time that a highly pathogenic bird flu virus, which is often fatal in birds, has been detected in U.S. cattle.

At least one person in Texas has been diagnosed with bird flu after having contact with dairy cows presumed to be infected, state officials said on Monday. The patient’s primary symptom was conjunctivitis; the individual is being treated with an antiviral drug and is recovering, according to the Centers for Disease Control and Prevention.

The virus has been identified as the same version of H5N1, an influenza subtype, that is circulating in North American birds. Scientists have not found evidence that the virus has acquired the mutations it would need to spread easily between humans, officials have said.

The risk to the general public remains low, experts said. But these developments add a worrying dimension to an avian influenza outbreak that has already affected millions of birds and sea mammals worldwide.