"Avian influenza is a viral disease that primarily infects birds, both domestic and wild. Certain strains of bird flu break the avian barrier and have been known to infect other animals and humans. Avian flu viruses are common among wild bird populations, which act as a reservoir for the disease. While rarely fatal in wild birds, avian flu is highly contagious and often fatal in domestic poultry, prompting strict biosecurity measures on farms. International trade restrictions imposed by countries to counter avian flu can have large economic effects. A strain of highly pathogenic avian influenza (H5N1) has spread throughout Asia since 2003, infecting mostly poultry, some wild birds, and a limited number of humans through close domestic poultry-to-human contact. The virus has also spread beyond Asia, reaching Europe in 2005 and the Middle East and Africa in early 2006. Over 250 million poultry have died or been destroyed internationally. The human mortality rate among the more than 250 people infected exceeds 50%. Fears that the virus could mutate to allow efficient human-to-human transmission and cause a human pandemic have prompted a massive political and public health response…Congressional agriculture committees have held hearings on avian influenza preparedness, and appropriators have increased funding for surveillance and other preparedness activities for poultry and wild birds."
CRS Report for Congress, RL33795