Highly Pathogenic Avian Influenza (HPAI)
Highly Pathogenic Avian Influenza, commonly known as bird flu, has been detected at multiple locations in Cascade County in April and May of 2022 - both in commercial poultry and in feral migratory birds. More information on HPAI is provided below, and can also be viewed at the Montana Fish, Wildlife, & Parks (FWP) website.
All commercial birds identified as having been exposed have been disposed of, however the possibility of further spread remains due to the large populations of wild and feral waterfowl and other migratory birds in the area.
Poultry producers should monitor their flocks for sudden onset of illness or sudden death. Common symptoms include swollen eyes, discolored comb or legs, significant drop in egg production, and significant reduction of water or feed consumption. Producers should also implement the following biosecurity measures:
- Prevent contact between wild or migratory birds and domestic poultry, including access by wild birds to feed and water sources.
- House birds indoors to the extent possible to limit exposure to wild or migratory birds.
- Limit visitor access to areas where birds are housed.
- Use dedicated clothing and protective footwear when caring for domestic poultry.
- Immediately isolate sick animals and contact your veterinarian or the Montana Department of Livestock.
Transmission from birds to humans is possible but very rare, and no human infections have been identified in Montana in 2022.
Any suspected cases of HPAI in poultry or other commercial flocks should be reported to the Montana Department of Livestock at 406-444-2976. Sick or dead wild birds should be reported to the Montana Fish, Wildlife & Parks at 406-577-7880.
HPAI Frequently Asked Questions
Courtesy of Montana Fish, Wildlife, & Parks - see more here.
What is avian influenza virus?
Avian Influenza (AI) virus is a naturally occurring virus of birds. AI viruses are classified into two groups, based on the severity of disease they cause in infected poultry. Low pathogenic Avian Influenza viruses (LPAI) generally cause no clinical illness, or only minor symptoms in birds. Highly Pathogenic Avian Influenza (HPAI) viruses are extremely infectious and fatal to poultry and some species of wild birds.
Does HPAI infect humans?
Human infections with HPAI have generally occurred after close and prolonged contact with infected birds or the excretions/secretions of infected birds. There have only been two human cases associated with the virus that is causing this outbreak. The first occurred in the U.K. in a person who did not have any symptoms and who raised birds. The second was a man in Colorado who had direct exposure to poultry and was involved in the culling (depopulating) of poultry with presumptive H5N1 bird flu. The patient reported fatigue for a few days as their only symptom and has since recovered.
These cases do not change the human risk assessment for the public, which CDC considers to be low. However, people who have job-related or recreational exposure to infected birds are at a higher risk of infections and should take appropriate precautions to prevent exposure.
Montanans should avoid contact with sick or dead wildlife when possible. If a bird must be collected (to keep it away from pets, children, raptors etc.), disposable gloves should be worn. A plastic bag should be used to cover and scoop up the carcass. The bag should be tied/sealed and placed in a second bag before being disposed of. A mask and eye protection can be used for additional protection from splashing of body fluids. Even if a bird is not suspected to have died from a contagious disease, gloves should always be worn if a dead animal must be handled for disposal.
What precautions should be taken by hunters?
While there is no evidence that any human cases of avian influenza have ever been acquired by eating properly cooked poultry products (CDC), bird hunters should follow these simple precautions when processing or handling wild game:
- Do not harvest or handle wild birds that are obviously sick or found dead.
- Dress/clean birds outdoors in open air when possible.
- Wear disposable latex or rubber gloves while cleaning game. For extra protection, wear a mask and eye protection.
- 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—one part chlorine bleach to 10 parts water.
- Separate raw meat, and anything it touches, from cooked or ready-to-eat foods to avoid contamination.
- Cook game meat thoroughly to an internal temperature of at least 165°F.
- Hunters who have domestic poultry at home should take precautions to avoid bringing the virus back to their flock on skin, clothing, and shoes.
- People and equipment that have been in contact with wild game birds should avoid contact with back yard poultry flocks.
Where does HPAI occur?
HPAI H5N1 was detected in Southeast Asia in 1996 and has since spread across Asia into Europe and Africa. H5N2 was detected in a Texas commercial chicken flock in 2004. From December 2014 through June 2015, the U.S endured a significant outbreak, with more than 200 cases of HPAI found in commercial and backyard poultry, as well as wild birds, across the country. The first known case of HPAI (H5N2) in Montana was detected in a captive Gyrfalcon in March 2015. Shortly after the virus was detected in the gyrfalcon, H5N2 was detected in a back yard poultry flock in Judith Basin County.
In December 2021, HPAI was once again detected in North America. Initial detection was in Newfoundland and Labrador. In February 2022, the virus was detected in a wild goose in Nova Scotia. HPAI was detected in South Carolina in January 2022 and has now been detected in all four bird migration flyways.
What bird species are affected by HPAI?
Domestic poultry such as turkeys and chickens are very susceptible to infection with HPAI and the virus is highly fatal in these species. Some wild waterfowl such as ducks and geese may carry the virus without exhibiting signs of illness; however, some infected waterfowl do develop symptoms and die. Birds of prey (owls, falcons, hawks, eagles) also appear to be very susceptible to disease and may become infected by consuming infected waterfowl. Wild gallinaceous birds such as turkeys, quail, and sage grouse, and scavengers such as ravens, crows and gulls may be susceptible, but at this time HPAI has not been implicated in large scale mortality events of these species. Eight turkeys did die from the virus in Montana in April 2022. The wild bird species experiencing the greatest level of mortality in this outbreak include snow geese, Canada geese, great-horned owls, turkey vultures, and hawks. The detection of HPAI virus in a chickadee in Minnesota during the 2015 outbreak indicates that a wide variety of bird species may be vulnerable to the HPAI viruses recently detected in the United States.
How does the virus spread from bird to bird?
The virus is shed in oral and nasal secretions and feces of infected birds, and can be spread via aerosol, direct contact with infected birds, contaminated drinking water, or fomites (any inanimate object or substance capable of carrying infectious organisms) (Western, 2009). The role of migratory birds in the spread of Highly Pathogenic Avian Influenza is still being investigated, but asymptomatic waterfowl are believed to be a primary reservoir of the virus.
What are the symptoms of HPAI in birds?
HPAI may cause significant disease in wild birds, depending on the specific virus and the host species. In some cases, birds can be infected and actively shedding virus without exhibiting signs of disease.
Symptomatic birds may exhibit any number of symptoms including respiratory distress, weakness, neurologic impairment (lack of coordination), seizures, and death, but are usually simply found dead.
What can Montanans do to help?
Investigation of morbidity/mortality events in wild birds offers wildlife professionals the best opportunity to detect the highly pathogenic avian influenza virus. The public is encouraged to report unusual or unexplained cases of sickness and/or death of wild birds by calling their local FWP office.
Wildlife health staff will work with local wildlife staff on a case-by-case basis to determine the appropriate response to sick/dead bird reports from the public. In some cases, birds will be collected for testing. Once the virus is documented in a variety of species in a county, the need for continued testing is not usually necessary. FWP is still prioritizing testing for sick/dead birds in new counties, new or unusual species, or those found in close proximity to domestic poultry.
If a reported bird is not collected for testing, data collected from public reports of sick/dead birds will be recorded in a database to allow tracking of suspected cases (species, number, location).
HPAI outbreaks are often characterized by the following:
- Mortality events involving multiple waterfowl (ducks, geese, or swans) or other water birds (loons, grebes, coots, shorebirds, or wading birds such as egrets, herons, or cranes)
- More than 5 dead birds of any kind at one time in one location
- Mortality events involving individual raptors or other avian scavengers (ravens, crows, or gulls), particularly those observed near locations with on-going waterfowl mortality
- Mortality events involving any wild bird species that:
- exhibit neurological signs, seizures, acute death, respiratory distress
- are found near facilities harboring domestic birds (or wild/captive) in which HPAI has been detected
Montanans may want to consider removing bird feeders, especially if they are near domestic poultry. While HPAI is not commonly detected in passerines, bird feeders do tend to result in congregation of many species of birds and buildup of fecal waste material. Bird feeders that are left in place should be cleaned regularly.
The public should be encouraged to avoid contact with sick or dead birds whenever possible. Even if a bird is not suspected to have died from a contagious disease, gloves should always be worn if a dead animal must be handled for disposal. In some cases, members of the public want to remove a carcass to prevent access by pets, children, or raptors. If a person wants to remove a carcass, they should wear gloves (disposable if possible), use a plastic bag to cover the carcass, then scoop it into the bag, then tie/seal it. The bagged carcass should be double-bagged and disposed of in a manner to prevent access to raptors which may be infected from consuming carcasses.
Criteria for wildlife professionals for prioritizing HPAI suspects for testing:
- Mortality involving wild bird species where estimated number of dead exceeds 500 birds.
- Mortality involving wild birds of any species near facilities housing domestic birds in which HPAI has been detected.
- Mortality involving any number of gallinaceous birds such as wild turkeys, quail, and sage grouse if no other clear cause of death is identified.
- Mortality involving 5 or more waterfowl (ducks, geese, or swans) or other water birds (loons, grebes, coots, shorebirds, or wading birds such as egrets, herons, or cranes).
- Mortality involving any number of raptors, waterfowl, or avian scavengers (ravens, crows, or gulls) observed in the same or adjacent counties to confirmed HPAI in poultry or wild birds.
- Mortality involving any number of raptors or avian scavengers (ravens, crows, or gulls) near locations with ongoing waterfowl mortality.
- Mortality involving raptors, waterfowl, or avian scavengers (ravens, crows, or gulls) observed with clinical signs consistent with neurological impairment, which may include swimming or walking in circles, moving the head in a “jerky” motion, and holding the neck and head in an unusual position (more drastic than simply drooping). Neurological signs associated with HPAI infection are not well characterized; thus, please collect detailed descriptions of the observed signs and call the NWHC with questions. Video and photos are strongly encouraged.
- Wild raptors with neurologic/respiratory signs that die or are euthanized within 72 hours of admission to a rehabilitation facility. These birds should also be tested for lead toxicity if possible. Please also provide treatment records.
- Raptors held in captivity (i.e., falconer birds, rehabilitation facility) with sudden, unexplained morbidity/mortality after exposure to wild waterfowl or a known/suspect case of HPAI H5. NOTE: If your agency receives a report that falls outside of these criteria, but you suspect there is elevated potential for HPAI infection please do not hesitate to contact the NWHC.
Wildlife health staff will work with local wildlife staff to determine the appropriate response to sick/dead bird reports.
Whenever possible, avoid contact with sick or dead wildlife. If a HPAI mortality event is suspected and carcasses are being collected in a potentially contaminated environment, PPE should include mask, eye protection, gloves, outer layer of coveralls, and boots or shoes that can be cleaned and disinfected after work is completed (See FWP PPE policy, PPE for field necropsy). This will reduce the risk of introducing the virus to additional areas or birds. Carcasses collected for disposal should be triple bagged and disposed of in a manner to prevent access to raptors which may be infected from consuming carcasses.
How should sick/injured/orphaned birds be handled considering HPAI?
While the concern for HPAI is high, FWP will not be rehabbing waterfowl. To avoid inadvertently bringing HPAI into a rehab center, raptors that are sick or displaying neurologic symptoms should not be brought to a rehab center without prior permission. Birds should either be left alone or humanely euthanized, and properly disposed of if not submitted for testing. Use criteria above to determine which birds should be prioritized for testing. If you’re unsure, call the Wildlife Health Lab. PPE should be worn when handling or euthanizing birds, not only to limit human exposure to the virus, but also to reduce the risk of introducing the virus to new areas or other birds. Work areas/tools should be disinfected with 1:10 bleach: water solution or other effective disinfectant. Carcasses should be triple-bagged and placed in a garbage receptacle to prevent scavenging by susceptible raptors, if not submitted for testing.