Specific Avian Flu Viruses
Avian influenza A viruses do not normally infect people, but sporadic infections in people have occurred with some avian influenza A viruses. Illnesses in humans from avian influenza A virus infections have ranged in severity from asymptomatic to mild to severe and fatal disease. Human infections with avian influenza A viruses have most often occurred after contact with infected birds or their secretions or excretions. Three subtypes of avian influenza A viruses are known to infect people (H5, H7 and H9 viruses). Among these, Asian lineage H5N1 and H7N9 have caused the majority of infections in people.
- Page last reviewed: May 1, 2017
- Page last updated: September 26, 2017
- Content source:
- Centers for Disease Control and Prevention, National Center for Immunization and Respiratory Diseases (NCIRD)
- Page maintained by: Office of the Associate Director for Communication, Digital Media Branch, Division of Public Affairs