Avian influenza (bird flu)

The Washington Department of Agriculture (WSDA) in May of 2022 confirmed the presence of avian influenza in several backyard flocks across Washington State and WDFW has confirmed cases of the disease in wild birds as well. If you encounter sick or dead wild birds, please report them.

Avian influenza, also known as bird flu, refers to the disease caused by infection with avian (bird) influenza (flu) Type A viruses. These viruses occur naturally among wild aquatic birds worldwide and can infect poultry and other bird and animal species. Wild aquatic birds include ducks, geese, swans, gulls and terns, and shorebirds. Some aquatic birds such as dabbling ducks and other waterfowl are considered reservoir hosts for avian influenza A viruses; though these birds can be infected with the virus they often do not exhibit clinical signs of illness. 

Avian influenza A viruses are very contagious among birds through saliva, nasal secretions, feces, and contaminated surfaces. Avian influenza A viruses are classified into two categories: low pathogenic avian influenza (LPAI) and highly pathogenic avian influenza (HPAI). LPAI viruses cause either no signs of disease or mild disease in chickens/poultry (such as ruffled feathers and a drop in egg production). Most avian influenza A viruses are low pathogenic and cause few signs of disease in infected wild birds. In poultry, some low-pathogenic viruses can mutate into highly pathogenic avian influenza viruses. 

HPAI can sicken and kill domesticated birds such as chickens, ducks, and turkey. It is an extremely contagious, multi-organ systemic disease of poultry that can lead to high mortality rates and extensive economic impacts. HPAI is caused by some H5 and H7 subtypes of type A influenza virus.  

In March 2022 the World Organization for Animal Health (OIE) reported the confirmed presence of highly pathogenic avian influenza (HPAI) virus, H5 variant, in a wild bald eagle found in Vancouver, British Columbia. This is the first confirmed report of HPAI virus in the Pacific Flyway since 2015. The strain of HPAI virus found in the eagle is thought to be the same clade (a group of organisms composed of a common ancestor) as what has currently been found in the other North American Flyways (Central, Mississippi, Atlantic), and is the same strain that has been circulating in Europe in 2021 and 2022. 

The first confirmed cases of HPAI in wild birds in the United States were in falcons and ducks in Washington State’s Whatcom County in December 2014. The first domestic poultry cases were identified in 2015 and spread in backyard poultry flocks, commercial poultry, wild waterfowl, and wild and captive raptors (hawks, falcons). None of the HPAI strains circulating in North America have been identified as high risks to human health. While the risk of human infection with HPAI viruses is considered low at this time, human infections have occurred, notably with H5N1 and H7N9 viruses in Asia. Most infections with these two strains occurred after prolonged contact with birds. 

The Washington Department of Fish and Wildlife (WDFW) tests birds for bird flu viruses as funding to do so is available. From 2005 to 2011, WDFW tested over 10,000 wild birds. Viruses were found in about 10 percent of all birds tested, but none were associated with any illness or mortality in the sampled birds. 

More recently, in the summer of 2021 and winter of 2021/22, WDFW and federal partners, including the United States Department of Agriculture Animal Plant Health Inspection Services, tested over 700 wild birds. None were found to have HPAI viruses.  

Bird flu viruses are not easily transmissible from birds to people, but without proper hygiene, or if in prolonged contact with a sick bird, the risk increases and the virus can potentially evolve to spread between humans. While it is extremely unlikely that hunters or people feeding wild birds could contract bird flu, the following common-sense precautions are recommended to reduce the risk of contracting any wildlife disease: 

There has, to date, been no evidence of HPAI virus-related illness in humans in this country. However, humans can become infected through direct contact with or touching a surface contaminated by the saliva, mucous, or feces of an infected bird and then touching their mouth, nose or eyes, or by breathing in virus present in the air.  

Some recommended hygiene measures to prevent the spread of HPAI virus-related illness include:  

  • Wear disposable gloves when cleaning harvested birds or cleaning bird feeders. 

  • Do not dispose of processed carcasses in the field where they could be eaten by raptors. Bag them and place in the garbage, bury, or incinerate them. 

  • Take special precautions to ensure that all equipment (boots, clothes, vehicles, firearms) are cleaned and disinfected to prevent the spread of diseases. 

  • Do not harvest or handle wild birds that are obviously sick or found dead. 

  • Do not eat, drink, or smoke while cleaning game. 

  • Wash hands with soap and water or alcohol wipes immediately after handling game or cleaning bird feeders. 

  • Wash tools and work surfaces used to clean game birds with soap and water, then disinfect with a 10 percent solution of chlorine bleach. 

  • Separate raw meat, and anything it touches, from cooked or ready-to-eat foods to avoid contamination. 

  • Cook game birds thoroughly. Meat should reach an internal temperature of 155 to 165 degrees Fahrenheit to kill disease organisms and parasites. 

If you experience flu-like symptoms following contact with birds, contact your local health department. They can provide public health guidance and initiate symptom monitoring. In addition, the Centers for Disease Control and Prevention (CDC) recommend getting a seasonal flu vaccine every year. This will decrease the likelihood of being infected with human seasonal flu and bird flu at the same time. Additional animal and human health and safety information regarding avian influenza is on the U.S. Department of Agriculture Animal and Plant Health Inpspection Service website

If you see a sick bird that you suspect may have avian influenza, please report it to WDFW.

Additional information:  

USDA APHIS 2022 detections  

CDC HPAI virus 

WSDA website for Avian Influenza