As the Centers for Disease Control and Prevention (CDC) explains, bird flu is a disease caused by the influenza A virus. At the same time, recent CDC data shows that seasonal influenza A is rising across the U.

For influenza viruses, imperfection is a strength. They constantly mutate, producing new strains that challenge immune systems primed to fight earlier varieties. That’s what makes flu a life-long threat to humans and the animal species — mainly birds — that are vulnerable to it.

The bird flu virus that killed 20 big cats in Washington and a pet cat in Oregon and is circulating among cows, poultry and wild birds isn't yet a threat to the general public, experts say. Why it matters: The first human death from bird flu isn't indicative of an imminent crisis,

Bird flu is suspected to have caused the death of multiple wild birds recovered across the state last week, New Jersey Fish and Wildlife announced. At least seven snow geese, two Canada geese, and two hawks have yielded presumptive positive results so far for avian influenza,