How worried should you be about bird flu‪?‬ The Big Story

The latest strain of H5N1 avian flu has been doing some ... unusual things. It's infecting a wide swath of mammals. It's spreading rapidly among cattle in the United States, many of them along Canada's border. And it's now been found in the milk supply of those cows, though FDA officials say that pasteurization means the milk is still safe to consume.

It's clear this strain is different from previous versions of the virus. And scientists are watching it very closely. But to a world that has recently suffered through a pandemic, any new virus doing unusual things may seem terrifying. So: What happens next? How worried should you be?

GUEST: Dr. Scott Weese, infectious disease veterinarian at the Ontario Vet College at the University of Guelph