Bird flu in U.S. cows caught scientists by surprise. Canadian research has seen it coming since 1953
Even though 2024 marked the first time the H5N1 bird flu was reported in dairy cows, researchers have known for decades that influenza viruses can target the cells that make up mammary glands.
![Bird flu in U.S. cows caught scientists by surprise. Canadian research has seen it coming since 1953](https://i.cbc.ca/1.7212642.1716491685!/fileImage/httpImage/image.jpg_gen/derivatives/16x9_620/h5n1-dairy-cows.jpg)
![This year marked the first time a dangerous form of bird flu was reported in dairy cows. Two human cases linked to the outbreak also involved only eye infections. Were these curveballs from H5N1 (left)? Some scientists say earlier research warned about all these unusual possibilities. Left side: A micrograph of H5N1, a type of avian influenza A. Right side: A dairy cow in New Zealand.](https://i.cbc.ca/1.7212642.1716491685!/fileImage/httpImage/image.jpg_gen/derivatives/16x9_620/h5n1-dairy-cows.jpg)
Even though 2024 marked the first time the H5N1 bird flu was reported in dairy cows, researchers have known for decades that influenza viruses can target the cells that make up mammary glands.