Highly Pathogenic Avian Influenza

Did you know?  Highly Pathogenic Avian Influenza
What to know as a livestock owner and as a consumer

Content by: Susann Mikkelson

A strain of Avian Influenza (bird flu) virus has been transmitted to another species of livestock – namely, dairy cattle, in the first significant case of its kind in recent history. The Highly Pathogenic Avian Influenza A(HPIA) (H5N1) outbreak in dairy cows was first reported on March 25, 2024, according to the Centers for Disease Control. The CDC later confirmed the first human case of HPAI A on April 1st, the first instance of likely mammal-to-human transmission of such a virus.

The presence of HPAI was confirmed at a poultry facility in eastern New Mexico as of April 16th. The US Department of Agriculture (USDA) has confirmed HPAI in dairy cattle in New Mexico, Colorado, Texas, Idaho, Kansas, South Dakota, Michigan, Ohio, and North Carolina.

While experts believe this is rare, mammals – including livestock and humans – can be infected with HPAI A viruses, and can spread the infection to one another. This can occur when mammals eat infected birds, poultry, or other animals and/or if they are exposed to environments contaminated with the virus.

What is HPAI?

Avian Influenza is a common respiratory disease of birds caused by an influenza type A virus which can infect poultry – such as chickens, turkeys, pheasants, quail, domestic ducks, gees and guinea fowl, and wild birds – especially waterfowl. The HPAI pathogen occurs naturally in wild birds and is most often spread during the fall and spring migratory seasons. The virus can spread rapidly from flock to flock, and is often fatal to domestic poultry, but, according to the CDC, poses a low threat to humans.

Though it is uncommon for HPAI to affect cattle, USDA’s Animal and Plant Health Inspection Service (APHIS) has been tracking detections of HPAI in mammals in the US, particularly in dairy cattle, for many years. This has led to dairy farmers and veterinarians to be prepared for eventual illness. This includes testing of sick cattle, as well as training for large animal veterinarians, livestock inspectors, State Agricultural Department staff, Cooperative Extension agents, and others in coordinated efforts to address outbreaks and minimize impacts to consumers and agricultural operations.

What Livestock Owners Should Know

Backyard and Other Poultry Producers and Enthusiasts

The HPAI virus can cause sudden death in poultry. The most common signs of HPAI in poultry include decreased food and water consumption, lethargy, respiratory distress, nasal discharge, purple discoloration or swelling around the legs and head, a drop in egg production, and diarrhea.

Good biosecurity is the key to keeping poultry, other livestock, and our food supply safe:

  • Keep wild birds and rodents out of coops and away from backyard flocks and pet birds.
  • Secure feed bins and water and consider removing bird feeders to avoid attracting wild birds.
  • Keep visitors away from birds and avoid visiting other poultry farms or other people’s birds.
  • Wash hands and scrub boots before and after entering a poultry area. Wear disposable boot covers and coveralls, if possible. If you’ve been in areas frequented by waterfowl, change clothes and shoes before handling poultry.
  • Isolate new birds or those returning from shows for 30 days before introducing them to the flock.

With the increase of ‘backyard producers’ and pet bird owners, the USDA and our State Veterinarian ask for all producers, companion animal veterinarians and poultry enthusiasts to help protect backyard flocks and pets by informing clients and neighbors on how to recognize the signs and symptoms of HPAI and urge immediate reporting of sick birds. Rapid and thorough reporting is critical to stopping the spread of this disease. Reports can be made to your local Cooperative Extension Agent or Livestock Inspector, or by contacting the New Mexico Department of Agriculture. See further information at the end of this article.

Dairy and Other Livestock Producers and Owners

Dairy farms who have confirmed cases of HPAI on their farms often also reported finding deceased wild birds on their properties. In addition to transmission from birds, mechanical transmission of HPAI is being investigated. For dairies whose herds are exhibiting symptoms, on average, about 10% of each affected herd appears to be impacted, with little to no associated mortality reported among the animals.

According to dairy farms and veterinarians reporting on affected herds, most affected cows recover within two or three weeks. Check the resources below for further information.

At this time, there are no reports of confirmed or suspected cases of HPAI in other cattle or other species of livestock. However, New Mexico Veterinarians are being urged to check with other states on receiving requirements of ALL cattle prior to shipment.

What Consumers Should Know

The CDC believes that the current risk of HPAI spread to the human public from bird flu viruses is low. People who have job-related or recreational exposure to infected birds or animals, including cows, are at a greater risk of contracting HPAIA.

The USDA confirmed that dairy products remain safe to consume. The Pasteurization process kills harmful microbes and pathogens in milk, including the influenza virus. Even so, dairies are required to send only milk from healthy animals into processing for human consumption; milk from impacted animals is being diverted or destroyed so that it does not enter the food supply.

Milk loss as a result of symptomatic cows is limited to date, with no major impact on supply, and therefore should not impact the price of milk or other dairy products.

Resources and Contact Information

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