Information and Resources
Avian influenza refers to infection of birds with avian (bird) influenza (flu) Type A viruses. These viruses occur naturally among wild aquatic birds worldwide and can infect domestic poultry and other bird and animal species. Avian influenza viruses do not normally infect humans. However, sporadic human infections with avian influenza viruses have occurred, most following direct or close contact with infected poultry. This page offers resources and links to information about avian influenza for different audiences.
Avian Influenza A Virus Infections in Humans
Although avian influenza A viruses usually do not infect humans, rare cases of human infection with these viruses have been reported. Most human infections with avian influenza A viruses have occurred following direct or close contact with infected poultry. Illness in humans has ranged from mild to severe.
The spread of avian influenza A viruses from one ill person to another has been reported very rarely, and has been limited, inefficient and not sustained. However, because of the possibility that avian influenza A viruses could change and gain the ability to spread easily between people, monitoring for human infection and person-to-person transmission is extremely important for public health.
Avian Influenza: Information for Health Professionals and Laboratorians - This link provides information from CDC on testing, reporting, treatment, and infection control for suspected cases of avian influenza in humans. If you suspect avian influenza in a patient due to symptoms and recent travel/exposure/risk, please contact the Division of Epidemiology and Immunization immediately at (617) 983-6800 for further direction on specimen collection and next steps. For more information on testing and surveillance, please visit the Infection Control, Testing, and Surveillance page.
Avian Influenza A Virus Infections in Birds
Avian influenza refers to infection of birds with avian influenza Type A viruses. These viruses occur naturally among wild aquatic birds worldwide and can infect domestic poultry and other bird and animal species. Wild aquatic birds can be infected with avian influenza A viruses in their intestines and respiratory tract, but usually do not get sick. However, avian influenza A viruses are very contagious among birds, and some of these viruses can sicken and even kill certain domesticated bird species including chickens, ducks, and turkeys.
Infected birds can shed avian influenza A viruses in their saliva, nasal secretions, and feces. Susceptible birds become infected when they have contact with the virus as it is shed by infected birds. They also can become infected through contact with surfaces that are contaminated with virus from infected birds.
Avian influenza A viruses are classified into the following two categories: low pathogenic avian influenza (LPAI) A viruses, and highly pathogenic avian influenza (HPAI) A viruses, referring to the molecular characteristics of a virus and the virus’ ability to cause disease and mortality in chickens in a laboratory setting.
CDC’s Avian Influenza in Birds
- CDC’s Traveler Health Notices
- CDC’s Flu News and Spotlights
- US Department of Agriculture (USDA) Avian Influenza
- USGS National Wildlife Health Center Avian Influenza
- World Health Organization Influenza at the Human-Animal Interface (HAI) (PDF)
- Division 6.2 Infectious Substance Shipping Guide: Classification, Packing, Marking and Labeling (Doc)