 This is Morning Edition from NPR News. I'm A. Martinez. And I'm Michelle Martin. More people are catching bird flu. Five cases were recently detected in workers at a poultry farm in Colorado. Meanwhile, dairy herds are still testing positive. Federal health officials maintain that it's still possible to get a handle on the outbreak. But not everybody is so optimistic. NPR's Will Stone is with us now with the latest. Good morning, Will. Good morning. Do we know how these folks in Colorado caught the virus?