USGS Frequently Asked Questions

Answer:

• This particularly virulent new strain of highly pathogenic avian influenza (HPAI H5N1) has spread throughout a large geographic area in Asia, Europe, and Africa since it was first documented in 1997 in Asia, and has caused the largest and most severe outbreaks in poultry on record.
• The human cases to date have been in Eastern Europe (Turkey) and Asia, primarily in Cambodia, China, Indonesia, Thailand, and Vietnam, and have been the result of direct or close contact with domestic (not wild) birds, especially chickens.
• Unlike most avian influenza viruses, this new strain of H5N1 has caused mortality in over 80 species of wild birds.