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Avian Flu (Bird Flu)

What is avian influenza?

There are four types of influenza viruses, A, B, C, and D. Avian influenza (AI) refers to the infection of birds with avian influenza type A viruses. This infection affects multiple bird species throughout the world. There are many subtypes of avian influenza viruses (AIV) based on a combination of two proteins, hemagglutinin (H) and neuraminidase (N). There are 16 H subtypes and 9 N subtypes. AIVs are further classified based on their ability to experimentally produce disease and mortality in chickens. Highly pathogenic subtypes (HPAI) produce disease and are often fatal, while low pathogenic subtypes (LPAI) are often asymptomatic or mildly symptomatic in chickens. The terms “HPAI” and “LPAI” are not associated with severity of illness in humans. Avian influenza is currently considered a low threat to human health.

What animals get avian influenza?

AI affects wild and domestic bird species, primarily waterfowl, raptors, and domestic poultry. Wild Turkeys can also be affected by avian influenza, but this is rare. HPAI can quickly decimate an entire flock of poultry. Raptors can become infected by eating infected prey or by coming in contact with surfaces that are contaminated with the virus. Some subtypes of AIV can affect mammals such as pigs, cats, horses, dogs, and ferrets, as well as humans. In 2022 cases of AI infection in red foxes were detected in the United States for the first time in Wisconsin, Michigan, Iowa, and Minnesota. Wild land birds (such as birds that use backyard feeders) can carry the virus without becoming sick.

In March 2024, the avian influenza subtype H5N1 was detected in domestic goats and dairy cattle.

What is the status of avian influenza?

Three subtypes have been detected in the United States, H5N1, H5N2, and H5N8:

  • H5N1 detected in the United States is a subtype with a reassortment of genes from HPAI H5 Eurasian viruses and LPAI viruses from North America. This is the strain that is currently causing most or all of the detections in North America.
  • H5N2 was first detected in British Columbia, Canada in December 2014. This H5N2 is a reassortment of Eurasian H5 and North American N2 viruses.
  • H5N8 is a Eurasian subtype first detected on the West Coast in wild birds in December 2014. A new variation of this subtype was detected in Dubois County, Indiana in January 2016.

A large outbreak of AI in the U.S. occurred in 2015, when subtype H5N2 affected more than 49 million domestic birds across 21 states. By March 2015, H5N2 was detected in the Midwest and, as of June 9, 2015, 21 states reported HPAI. Minnesota and Iowa experienced the largest number of cases (105 and 74 facilities, respectively). All 2015 HPAI cases in the Midwest consisted of the H5N2 subtype except the case in Indiana. The subtype detected in Indiana in spring 2015 was the Eurasian H5N8 subtype, which had been previously detected only along the West Coast.

In 2021, a new outbreak of H5N1 HPAI began in North America. The first confirmation was in December 2021, in a Newfoundland and Labrador exhibition farm. Multiple bird species including chickens, turkeys, geese, ducks, emus, Guinea fowl and peafowl were exposed. As a result of this outbreak, 360 birds died from AI, and another 59 were culled. Since this time, a second noncommercial farm in Newfoundland and Labrador also experienced an outbreak and H5N1 was confirmed in a Canada goose in Nova Scotia. In January and February 2022, wild bird species in multiple Eastern U.S. states tested positive for this strain. As of June 2023, HPAI has been confirmed in domestic birds in 47 states and has been confirmed in wild birds in 49 states and the District of Columbia.

On March 25, 2024, HPAI H5N1 was detected in dairy cows in Texas. It has since been detected in dairy cattle in Michigan, Ohio, North Carolina, New Mexico, Kansas, Colorado, Idaho, and South Dakota. On April 1, 2024, a cattle worker in Texas tested positive for H5N1. The person’s only reported symptom was eye redness. This case marks the second person who has ever tested positive for H5N1 in the United States.

You can track wild bird AI findings on the USDA APHIS website. To see the current distribution of positive detections in wild and domestic birds, visit the National Wildlife Health Center’s webpage. To see a current update of HPAI in domestic livestock, visit the USDA’s Highly Pathogenic Avian Influenza Detections in Livestock page. If you have been exposed to a poultry flock or domestic livestock herd that is infected with AIV, please call the Indiana Department of Health at 317-233-1325.

What is the status of avian influenza in Indiana?

In February 2022, H5N1 HPAI was first confirmed in a commercial turkey farm in Indiana in Dubois County. Through 2022 and 2023, 10 commercial flocks and six backyard flocks tested positive for AI, with the last positive test in May of 2023. On Jan. 24, 2024, another commercial poultry farm tested positive for HPAI H5N1. Find up-to-date information on HPAI in poultry facilities  at the Indiana State Board of Animal Health’s (BOAH) HPAI website.

The DNR does regular surveillance for avian influenza using reports from the public that are submitted to the Sick and Dead Wildlife Reporting tool. The DNR has also partnered with the USDA to do surveillance on hunter-harvested waterfowl. To date, a total of 84 wild birds have tested positive for HPAI H5N1 in Indiana, including American coots, green-winged teal, American white pelican, bald eagle, barred owl, blue-winged teal, Canada goose, double-crested cormorant, Eastern screech owl, gadwall, great horned owl, mallard, peregrine falcon, red-tailed hawk, redhead duck, snow goose, tundra swan, Northern pintail, Northern shoveler, wood duck, American black duck, and an unidentified hawk. These wild birds have tested positive in 20 counties. Find a list of all wild birds that have tested positive for AI on the USDA APHIS website.

What AIV surveillance is DNR Fish & Wildlife doing?

In response to HPAI outbreaks in commercial poultry farms around the state, DNR Fish & Wildlife (DFW) has partnered with USDA-APHIS to increase wild bird surveillance. DFW personnel continually conduct opportunistic sampling of wild birds across the state for AIV. If you encounter a wild bird species that is displaying clinical signs of AIV, please report it using the Indiana DNR Sick and Dead Wildlife online reporting tool.

What is the risk to people?

Very few types of AI can infect humans. The Centers for Disease Control and Prevention (CDC) considers the risk to people from AI viruses to be low. The U.S. has a strong AIV surveillance program that has been in place for many years. Federal, state and industry partners respond quickly to outbreaks and follow five general steps: 1) Quarantine, 2) Eradicate, 3) Monitor, 4) Disinfect, and 5) Test.

If you have been exposed to a poultry flock or domestic livestock herd that is infected with AIV, please contact the Indiana Department of Health for additional guidance at 317-233-1325. Find more information on human exposure. Learn more from the CDC.

What are the signs of HPAI in birds?

Clinical signs of HPAI in birds include one or more of the following:

  • Sudden death
  • Neurological impairment (e.g., lack of coordination, swimming in circles, tremors, twisted neck)
  • Lack of energy and appetite
  • Decrease in egg production, soft-shelled or misshapen eggs
  • Swelling of the head, eyelids, wattles, hocks, and comb
  • Purple discoloration of wattles, combs, and legs
  • Nasal discharge, cough, sneezing, lack of coordination, and diarrhea

How is HPAI spread?

Once introduced, HPAI can spread quickly through manure, equipment, vehicles, egg flats, crates, people’s clothing and shoes, water, and, potentially, feed. Research continues to determine if there are other vectors. AIV can remain viable for long periods of time in water and at moderate temperatures. The virus can survive indefinitely in frozen conditions.

How can you prevent the spread of AIV?

Practice proper hygiene and good biosecurity. If you keep birdfeeders and birdbaths on your property, clean them regularly with hot water and a 10% bleach solution, rinse thoroughly, and then allow birdfeeders to completely dry before refilling. Clean up birdseed that has fallen below birdfeeders. Do not feed wild birds, especially waterfowl, near domestic flocks. If you come in contact with any bird that appears unhealthy, wash your hands with soap and water, and change clothing and shoes before coming in contact with a domestic flock or captive birds. Read more about biosecurity for domestic birds.

We also encourage hunters to practice safe handling of harvested birds:

  • Do not harvest birds that appear obviously sick or found dead
  • Process birds outdoors or in a well-ventilated area
  • Wear gloves and wash hands before and after handling the carcass
  • Disinfect all equipment that comes into contact with dead birds (e.g., knives, surfaces)
  • Refrain from eating, drinking, smoking, and touching your eyes during processing
  • Double bag feathers and all bird remains prior to disposal. Place bird remains in the inner bag and tie closed. Dispose of gloves in the outer bag before tying closed.
  • Cook meat thoroughly

More information about safe hunting practices can be found at USDA-APHIS.

Report sick birds or unusual bird deaths to state/federal officials through the following:

Poultry or Domestic Mammals: BOAH healthy bird hotline: 1-866-536-7593
Wild Birds: DNR Fish & Wildlife: Sick or dead wildlife can be reported online at
Human Health: For human health concerns, contact the Indiana Department of Health at 317-233-1325

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