Bird flu typically spreads among birds, but there have been recent outbreaks among cattle in the U.S., and one Texas man contracted the virus from sick cows. Here’s why so many experts are worried about a possible new pandemic.

The beef supply remains safe, the USDA says. But the discovery of bird flu in the muscle of a deceased cow raises new concerns.

While cases are rising, with over 100 herds affected nationwide, scientists worry that not enough testing is being done to understand the outbreak’s full scope. Florida has yet to record a case in cows. Michigan has reported the most of any state, with infections logged in 25 herds.

Five cows in the U.S., including some in Ohio, have died from bird flu or been slaughtered because of it. What does it mean for your milk and beef?

Iowa politicians are urging the US Department of Agriculture to roll out a vaccine for bird flu, now in dairy cows. But there could be downsides.