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.

The Bird Flu or Avian Influenza is a type of viral infection that spreads in birds and some mammals. The H5 bird flu is causing outbreaks in wild birds, poultry, other animals and sporadic human cases.

A child ill with fever and conjunctivitis in San Francisco tested positive for bird flu but had no known source of transmission.