Bird flu spreads to mammals, including US dairy cows and sea lions in South America

Since 2020, avian flu has been tearing through bird populations across the globe - even being detected in Antarctica's penguins. This month, the Centers for Disease Control and Prevention reported what might be the first documented case of the virus being transmitted from a mammal to a human - from a cow to a person working on a dairy farm in Texas. The World's host Carolyn Beeler spoke to Massimo Palmarini, the director of the Center for Virus Research at the University of Glasgow in Scotland, UK.