Washington wild ducks
Avian influenza ("bird flu") is a viral illness found in birds. Wild birds can carry a number of bird flu viruses, but most strains do not seriously affect them.
Bird flu viruses are unlikely to infect people who practice good hygiene when handling birds.
Occasionally bird flu viruses evolve into forms that are deadly to domestic chickens and turkeys. These viruses are known as "highly pathogenic avian influenza" (HPAI) viruses, a designation that refers to their ability to cause disease in domestic poultry, not in humans or any other animals.
In 1996, a particularly virulent form of bird flu caused by a strain of virus known as Asian HPAI H5N1 sickened and killed birds in Asia, Africa and Europe. After close contact with infected domestic birds, more than 100 people in Asia died from this Asian HPAI H5N1 virus. This strain of HPAI has not been detected in North America.
Since then, several different bird flu strains have been identified around the world in domestic birds, including HPAI in poultry farms with chickens and turkeys in British Columbia, Canada. After the disease was detected at a B.C. poultry farm in fall 2014, the Washington State Department of Agriculture increased random testing among poultry flocks in areas near the border with Canada and alerted veterinarians and bird owners around the state.
This heightened awareness led to a report in December 2014 of a gyrfalcon in northwest Washington that died after eating a wild duck. The gyrfalcon, which was legally used for hunting by a Whatcom County falconer was tested and confirmed to have HPAI. In addition, a northern pintail duck that was part of a group of waterfowl that died of aspergillosis (an unrelated fungal infection) near Wiser Lake in Whatcom County, tested positive for carrying the HPAI bird flu virus.
Since that time, HPAI strains have spread quickly in the Pacific Flyway and other flyways. They have been found in backyard poultry flocks, commercial poultry, wild waterfowl, and wild and captive raptors (hawks, falcons, etc.). (See USDA's Update on Avian Influenza Findings in the Pacific Flyway.)
None of the HPAI strains circulating in North America have been identified as risks to human health.
Because of the potential effects of the new strains on wild raptors, we are asking bird hunters to not dispose of processed carcasses in the field where they could be eaten by raptors. Instead, carcasses should be bagged and placed in the garbage, buried or incinerated.
It is also highly recommended that hunters who have domestic poultry or other birds at home, or who may visit domestic poultry markets or exhibitions (such as fairs), take special precautions to ensure that all equipment (boots, clothes, vehicles, etc.) are cleaned and disinfected to prevent the spread of diseases (see http://www.aphis.usda.gov/publications/animal_health/2015/fsc_hpai_hunters.pdf).
Bird flu viruses are transmitted among birds through respiratory secretions and fecal droppings. The virus is not easily transmissible from birds to people, but health officials are concerned that without proper hygiene, it could develop into another form that spreads readily from person to person. While it is extremely unlikely that hunters or people feeding wild birds could contract bird flu from wild birds, the following common-sense precautions are always recommended to reduce the risk of contracting any wildlife disease:
- Do not harvest or handle wild birds that are obviously sick or found dead.
- Wear disposable gloves while cleaning game or cleaning bird feeders.
- 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.
Dogs used in wild bird hunting are not considered at risk of acquiring bird flu, since there have been no documented cases of the virus infecting dogs. There have been cases of cats acquiring the Asian H5N1 strain of bird flu in other parts of the world, but no cats have been documented with the currently circulating HPAI strains in North America. Dog and cat owners should consult their veterinarian for more information about influenza in pets.
The Washington Department of Fish and Wildlife (WDFW) has been collaborating for the past several years with the National Wildlife Health Center, the U.S. Fish and Wildlife Service (USFWS) and the U.S. Department of Agriculture (USDA) in a nationwide surveillance effort for early detection of highly pathogenic avian influenza in wild birds.
WDFW is part of a state network for collection and testing of dead birds. Die-offs of wild birds should be reported to WDFW by calling 1-800-606-8768. If the bird deaths appear unusual, samples are sent to veterinary laboratories to test for diseases, including bird flu.
From 2005-2011, WDFW tested over 10,000 wild birds for bird flu viruses. Bird flu viruses were found in about 10 percent of all birds tested, but none were associated with any illnesses or mortality.