Millions of birds have died because of bird flu. Human activity has helped make the virus more deadly.

Farmworkers have been exposed to milk infected with the bird flu virus. But there has been virtually no testing on farms, and health officials know little about who may be infected.

Fayette Janitorial Service was also ordered to change practices that the Labor Department said had led to the hiring of at least two dozen children in dangerous slaughterhouses and meatpacking facilities.

The fast-casual chain aims to be climate neutral by 2027, but beef is a big contributor to climate change.

Other states have also considered restrictions, citing concerns about farmers’ livelihoods and food safety, though the product isn’t expected to be widely available for years.

A genetic analysis sheds light on when the outbreak began, how the virus spread and where it may be going.