Highly Pathogenic Avian Influenza (Bird Flu) Outbreak in Cattle

Last updated: 07/09/2024

The New York State Department of Health (NYSDOH) is working with the New York State Department of Agriculture and Markets (AGM) to monitor a national outbreak of highly pathogenic avian influenza (HPAI), 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 currently circulating in the United States, has been found in wild birds and occasionally domesticated poultry (such as chickens and turkeys) in the United States since 2022.

Since March 2024, 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 nose of cows on these farms.

Information about the current outbreak in cattle is below. For more information about avian influenza, see Questions and Answers about Avian Influenza (Bird Flu).

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." The virus is found in high concentration in milk, so avian influenza might be spread from one cow to another when multiple cows share the same milking machines.

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

Can people get sick from this strain of avian influenza?

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

Rarely, H5N1 avian influenza can be 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 farms who worked with infected cattle. As of now, all the human cases in the United States have had mild disease and made full recoveries.

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 mammals in New York.

Is it safe to drink milk?

Yes, drinking milk from the commercial milk supply is safe because it is pasteurized.

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.

How can farm workers protect themselves?

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

To reduce this risk, anyone who works directly with birds or cattle should wear appropriate personal protective equipment (PPE) around animals that might be or are known to be ill with avian influenza. This PPE should include an N95 respirator, eye protection, gloves, footwear, fluid-resistant coveralls, head cover or hair cover, and a waterproof apron, if needed for job task. More information about PPE for farmworkers can be found here.

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, 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 New York State Department of Agriculture and Markets (AGM) and the Centers for Disease Control and Prevention (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?

The New York State Department of Agriculture and Markets (AGM) conducts biosurveillance for avian influenza in sick domestic poultry in New York. If avian influenza is detected in domestic poultry, AGM 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?

Testing for H5N1 avian influenza in ill cattle and other animals is performed at the Animal Health Diagnostic Center at Cornell University.

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.

If avian influenza were to be detected in dairy cattle in New York, AGM would work collaboratively with 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, to which the virus is sensitive.
  • We are still learning about how the presence of this virus in cattle may impact human health.

Additional Information