Detection of Avian Influenza Confirmed in Montana

On, Friday April 14, 2023, the Montana Department of Livestock (MDOL) confirmed Highly Pathogenic Avian Influenza (HPAI) in a Rosebud County backyard poultry flock. This is the 17th HPAI affected flock in the state of Montana linked to the 2022 outbreak of HPAI infections in the United States. The disease was last confirmed in poultry in the state in January.

The disease caused 100% mortality in the Rosebud County backyard chicken flock, which numbered several dozen birds. The animals did not show obvious signs of illness prior to sudden death. To prevent further spread, infected premises are placed under quarantine and any remaining birds are euthanized. In addition to restrictions on the affected flock, the department is contacting flock owners within 6.2 miles of the affected premises to provide education on minimizing risk for disease exposure.

"In past years, the department has seen cases of HPAI ramp-up on the East Coast, then move west with the season.” Stated Dr. Merry Michalski, a veterinarian with the Department of Livestock, “We are noticing a similar trend this year. Therefore, we expect that the risk of HPAI to Montana poultry will increase with the spring migration of waterfowl and other wild birds.”

Migratory waterfowl are the primary source of avian influenza. Wild birds can appear healthy but carry infection and shed the virus in the feces, saliva, and respiratory secretions. Domestic poultry become infected through direct contact with infected wild birds, or through contact with contaminated objects, equipment, or the environment. With this new Montana detection, the department is reminding bird owners to house birds indoors and prevent exposure to wild birds and wild bird bodily fluids. This recommendation also applies to birds enrolled in certified organic programs. Enrolled organic producers should contact their certifier before moving birds indoors to ensure program compliance.

Sick poultry can exhibit signs such as swollen eyes, discolored comb and legs, a significant drop in egg production, or decrease in water and feed consumption. However, the most common presentation with this virus variant has been sudden death of multiple birds within a flock.

Biosecurity measures to protect flocks include:

● 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 birds.

Report sudden onset of illness or high death loss in domestic poultry to your veterinarian or MDOL at (406/444-2976) immediately. If you find sick or dead wild birds, please contact your local Fish, Wildlife, and Parks (FWP) Warden, Biologist or Regional office, or call the FWP wildlife veterinarian (406/577-7880). MDOL would like to remind veterinarians who are submitting samples suspicious for HPAI to contact Montana Veterinary Diagnostic Laboratory (MVDL) prior to shipment so laboratory staff are prepared to receive the sample and follow an increased biosecurity protocol.

While HPAI is considered a potentially zoonotic disease, the Centers for Disease Control and Prevention (CDC) continues to consider the risk to people from wild birds, backyard flocks, and commercial poultry to be low. However, it is advisable to wear gloves and face protection when working with sick or dead birds. The department also recommends that individuals practice good hand hygiene and refrain from eating and drinking whenever working with livestock and poultry. Existing safeguards to keep food safe and wholesome are sufficient to protect people, and the food supply in the United States is one of the safest in the world. As a reminder, the US Department of Agriculture recommends cooking poultry to 165 degrees Fahrenheit.

MT FWP continues to track HPAI infection in predatory mammals (i.e.: fox, skunk, and bears). Additionally, there is concern for transmission to domestic cats and dogs that ingest dead infected birds. Mammals with HPAI may exhibit neurologic symptoms, such as incoordination or increased aggression. If you notice abnormal neurologic behavior in your pet, please contact your veterinarian and provide any history of recent ingestion of a deceased bird by the pet. Rabies is also a concern when dealing with animals that exhibit neurologic symptoms.