The simmering threat of bird flu may be inching closer to boiling over.

This year has been marked by a series of concerning developments in the virus’ spread. Since April, at least 64 people have tested positive for the virus — the first U.S. cases other than a single infection in 2022. Dairy cow herds in 16 states have been infected this year. The Centers for Disease Control and Prevention confirmed the country’s first severe bird flu infection on Wednesday, a critically ill patient in Louisiana. And California Gov. Gavin Newsom declared a state of emergency this week in response to rampant outbreaks in cows and poultry.