For the first time, a virulent strain of bird flu has been detected in U.S. dairy cows. Fragments of the virus have also been found in commercial milk. Today, health reporter Lena Sun shares the latest on the outbreak and why the risk to humans remains low.

In recent years, H5N1 bird flu has become widespread among wild birds around the world and has spread to mammals like seals and squirrels. It can be fatal and has resulted in the deaths or cullings of tens of millions of chickens in the United States alone.

Then in March, another concerning development caught the attention of scientists around the world: H5N1 was found in a herd of dairy cows for the first time in the United States. The virus has since been identified in cows in at least nine states, and preliminary testing of the virus fragments in commercial milk indicate the outbreak may be more widespread than previously thought.

While the cases in cows appear to be mild so far, a dairy worker also became sick last month with mild symptoms, marking the second known U.S. case of this type of bird flu in a human.

Today, national health reporter Lena Sun joins “Post Reports” to share the latest on what is known and not known about the growing outbreak, and the precautions people can take to stay healthy.

Read more:

As bird flu spreads in cows, fractured U.S. response has echoes of early covid

Bird flu explained: How it spreads, milk and egg safety and more

How prepared the U.S. is for a bird flu pandemic

Today’s show was produced by Elana Gordon. It was edited by Lucy Perkins and mixed by Sean Carter. Thanks to Rachel Roubein and Tracy Jan.

Subscribe to The Washington Post here.