Sick Birds
According to the Centers for Disease Control and Prevention (CDC), influenza has been a common communicable disease in birds for centuries (see "Connecting the Dots," cover story, November/December 2004). Most strains are confined only to birds and are generally non-lethal, much like human influenza viruses. Recently though, there have been questions raised over the H5N1 strain of avian influenza that has been crossing over into human beings in Southeast Asia.






