Highly Pathogenic Avian Influenza (Bird Flu) Outbreak in Cattle

The New York State Department of Health (NYSDOH) is working with the New York State Department of Agriculture and Markets (NYSDAM) to monitor a national outbreak of highly pathogenic avian influenza, also called avian flu or bird flu, that has appeared in dairy cattle.

Highly pathogenic avian influenza is a virus that causes severe illness and death in birds. The highly pathogenic avian influenza H5N1 strain that is currently circulating has been found in wild birds and occasionally domesticated poultry (such as chickens and turkeys) in the United States since 2022.

Since March 2024, the US Department of Agriculture (USDA) has confirmed that cows on dairy farms in multiple states have tested positive for H5N1 avian influenza. The virus has been found in raw (unpasteurized) milk and secretions from the noses of cows on these farms.

Information about the current outbreak in cattle is below.

What is Highly Pathogenic Avian Influenza?

See Questions and Answers about Avian Influenza (Bird Flu)

How is avian influenza transmitted between cows and from cows to humans?

We are still learning about how cows spread avian influenza to other cows. One possible way it spreads on farms is through "fomite transmission" (spread through contaminated objects). The virus is found in high concentration in milk, so avian influenza is likely spread from one cow to another when multiple cows share the same milking machines. Avian influenza virus transmission between farms is associated with fomites (such as the movement of vehicles between farms) or the movement of infected animals between farms.

Dairy workers can also be exposed to avian influenza through cow's milk, especially when milk splashes into the workers' eyes, nose, or mouth. Dairy workers can likely also be exposed from contact with other animal secretions, such as nasal mucus.

Can people get sick from this strain of avian influenza?

The risk to the general public of getting sick from this strain of avian influenza is low.

Rarely, H5N1 avian influenza has been passed to humans who have had direct contact with infected birds and mammals, including cattle. Several people have had confirmed H5N1 avian influenza infections in the United States since 2022, including workers on dairy and poultry farms who worked with infected animals. As of now, all people who have been sick with H5N1 avian influenza in the United States have fully recovered from their illness.

To date, this H5N1 strain of avian influenza has not spread from person to person.

Has avian influenza been detected in New York?

To date, there have been no human cases of avian influenza and no detections in cattle in New York.

Since 2022, H5N1 avian influenza has been found in domestic poultry, wild birds, and a few species of wild mammals in New York.

Is it safe to drink milk?

Yes, drinking pasteurized milk is safe.

Pasteurization, or heating milk to kill germs, kills the avian influenza virus, so people cannot get infected from drinking pasteurized milk. Raw (unpasteurized) milk is never safe to drink, and NYSDOH strongly recommends that people do not drink raw milk or eat products made from raw milk.

What measures can be put in place to help protect farm workers?

Individuals who work with infected poultry or dairy cattle are at increased risk of avian influenza.

To reduce this risk, some people who work directly with birds or cattle should wear personal protective equipment (PPE). Which PPE workers should wear depends on their risk of exposure according to the table below:

Exposure level Work Task/Setting Recommended PPE
High

Contact with confirmed or potentially infected (sick) animals, either dead or alive.

Contact with raw milk, other secretions (bodily fluids), udders, or viscera (internal organs) from animals on a farm with confirmed or potentially infected (sick) animals.

Examples:

  • Working in milking parlor, including milking and cleaning.
  • Processing raw milk.
  • Working in pens with sick animals.
  • Culling (removing) sick poultry.
  • Doing some slaughterhouse tasks.
  • NIOSH Approved® particulate respirator
  • Safety goggles
  • Disposable gloves
  • Fluid-resistant coveralls
  • Head cover or hair cover
  • Boots or boot covers
  • Optional: Waterproof apron
  • Optional: Face shield
  • Optional: Outer work gloves
Medium

Contact with healthy, non-lactating (not producing milk) animals on a dairy farm with confirmed or potentially infected animals.

Contact with animals from a farm without confirmed or potentially infected animals when there are confirmed or potentially infected animals in the region.
Low

Contact with healthy animals and no infected animals in the region.

No contact with animals or animal secretions.

 None

Employers should provide appropriate PPE for their workers according to their exposure level and ensure that workers are appropriately trained to use PPE.

More information can be found on the Centers for Disease Control and Prevention (CDC) website:

For employers:

For farm workers:

Anyone working with animals should also:

  • Wash their hands thoroughly with soap and water throughout the day, especially after handling sick animals and before eating. If soap and water is not available, use an alcohol-based hand sanitizer containing at least 60% alcohol instead.
  • Avoid touching their eyes, nose, and mouth.
  • Never consume raw milk or raw milk products.

How is New York State and the Department of Health responding to H5N1 avian influenza?

While the risk of H5N1 avian influenza to people is currently considered low, the New York State Department of Health is preparing to respond in case H5N1 avian influenza is found in cattle or birds in New York.

We are working closely with other agencies including the NYSDAM and the CDC to stay up to date on the latest outbreak data.

If a person is exposed to an animal with avian influenza in New York, NYSDOH works with local health departments to monitor that person for flu-like illness and test them for H5N1 avian influenza if they develop symptoms.

What is biosurveillance?

Biosurveillance is a systematic process to survey the environment or location of interest for bacteria, fungi, viruses, or other pathogens that might cause disease in people, animals, or plants in support of detection and identification efforts and corresponding public health or safety. In other words, biosurveillance involves looking for problems like new viruses or emerging diseases before they become a larger problem.

What testing is done for avian influenza in sick birds in New York State?

NYSDAM conducts biosurveillance for avian influenza in sick domestic poultry in New York. If avian influenza is detected in domestic poultry, NYSDAM works collaboratively with the USDA to control spread to other flocks.

The USDA APHIS Wildlife Services program is responsible for conducting biosurveillance and testing for diseases, including avian influenza, among wild birds. The New York State Department of Environmental Conservation (DEC) works with USDA APHIS Wildlife Services to obtain samples for testing from wild waterfowl harvested by hunters. DEC is also testing any unusual die-offs of wild birds to help detect the spread of avian influenza. If you observe a group of ill or dead wild birds in one location, please contact your regional DEC wildlife office.

What testing is done for avian influenza in cattle in New York State?

The Animal Health Diagnostic Center at Cornell University tests for H5N1 avian influenza in ill cattle and other animals.

Lactating dairy cattle being transported in or out of New York State are required to have a negative H5N1 avian influenza test within seven days of interstate movement in accordance with a federal order issued by the USDA on April 29, 2024. New York State also requires certain non-lactating dairy cattle to be tested for H5N1 before being brought into New York State. During the 2024 fair season, lactating dairy cattle were required to test negative for H5N1 avian influenza within seven days prior to entering fairs or exhibitions in New York.

If avian influenza were to be detected in dairy cattle in New York, NYSDAM would work collaboratively with the USDA to control spread to other dairy herds and other species of animals.

What testing is done to detect animal-to-human spread of avian influenza in New York State?

People who are exposed to H5N1 while working with infected/potentially infected animals or their byproducts will be monitored for symptoms of avian influenza infection during any period of exposure to animals and for 10 days after their last exposure. Testing for H5N1 and treatment with antivirals would be offered immediately if someone reports symptoms after being exposed.

What is the difference now compared to the start of the COVID-19 pandemic?

  • Agriculture workers who are exposed to symptomatic animals are at higher risk.
  • We already have a well-validated diagnostic test for the virus.
  • We already have a number of antiviral drugs which are effective at treating the infection.
  • We are still learning about how the presence of this virus in cattle may impact human health.

Additional Information