There have been dozens of confirmed human cases of bird flu in the U.S. this year. Experts discuss the symptoms, risks and how to prevent getting sick.

H5N1 avian influenza, more commonly known as bird flu, has infected more than 100 million birds in the U.S. and almost 500 dairy cattle herds across 15 states. The virus has popped up in mammals including elephant seals,

The virus can be spread through direct contact with infected animals, but can also spread through contaminated barns and other environments.

A teenager in British Columbia is critically ill with Canada's first case of the H5N1 bird flu strain. While the virus has spread to humans in rare cases, experts say the risk of a pandemic is low as it doesn't transmit easily between people.