Influenza A in Mammals 2024

Influenza A in U.S. Dairy Cattle 2024

Overview: The U.S. Department of Agriculture (USDA), Food and Drug Administration (FDA) and Centers for Disease Control and Prevention (CDC), as well as state veterinary and public health officials, are continuing to investigate an illness among dairy cows that is causing decreased lactation, low appetite, and other symptoms. To date no similar illness, nor HPAI detections, have been reported in Canadian dairy cattle.

HPAI detections in U.S. dairy cattle

April 2, 2024. Influenza A detection in Idaho dairy cattle LINK


April 1,  2024. Influenza A detection in New Mexico dairy cattle LINK


March 29, 2024 HPAI detection in Michigan dairy cattle LINK

                           HPAI detection in Idaho dairy cattle LINK 

March 25, 2024  HPAI detection in Texas and Kansas dairy cattle LINK

Human HPAI Case in Dairy Worker

April 1, 2024—A person in the United States has tested positive for highly pathogenic avian influenza (HPAI) A(H5N1) virus (“H5N1 bird flu”), as reported by Texas and confirmed by CDC.

This person had exposure to dairy cattle in Texas presumed to be infected with HPAI A(H5N1) viruses. The patient reported eye redness (consistent with conjunctivitis), as their only symptom, and is recovering. The patient was told to isolate and is being treated with an antiviral drug for flu.

This infection does not change the H5N1 bird flu human health risk assessment for the U.S. general public, which CDC considers to be low. However, people with close or prolonged, unprotected exposures to infected birds or other animals (including livestock), or to environments contaminated by infected birds or other animals, are at greater risk of infection.

Highly Pathogenic Avian Influenza A(H5N1) Virus in Animals: Interim CDC Recommendations for Prevention of Human Infections

CDC recommendations for humans to reduce risk of HPAI infection
1. Recommendations for the Public
People should avoid unprotected (not using respiratory or eye protection) exposures to sick or dead animals including wild birds, poultry, other domesticated birds, and other wild or domesticated animals, as well as with animal feces, litter, or materials contaminated by birds or other animals with suspected or confirmed HPAI A(H5N1) virus infection. People should not prepare or eat uncooked or undercooked food or related uncooked food products, such as unpasteurized (raw) milk, or raw cheeses, from animals with suspected or confirmed HPAI A(H5N1) virus infection (avian influenza or bird flu).

2. People exposed to HPAI A(H5N1)-virus infected birds or other animals (including people wearing recommended PPE) should monitor themselves for new respiratory illness symptoms, including conjunctivitis (eye redness), beginning after their first exposure and for 10 days after their last exposure.

3. Recommendations for Farmers; Poultry, Backyard Bird Flock, and Livestock Owners; and Worker Protection
To reduce the risk of HPAI A(H5N1) virus infection, poultry farmers and poultry workers, backyard bird flock owners, livestock farmers and workers, veterinarians and veterinary staff, and responders should avoid unprotected direct physical contact or close exposure with sick or dead birds or other animals, carcasses, feces, milk, or litter from sick birds or other animals potentially infected or confirmed to be infected with HPAI A(H5N1) virus. Farmers, workers, and responders should wear recommended PPE such as an N95 filtering facepiece respirator, eye protection, and gloves, and perform thorough hand washing after contact. (e.g., see: PPE recommended for poultry workers) when in direct contact with sick or dead birds or other animals, carcasses, feces, or litter from potentially infected birds or other animals, and when going into any buildings with or that have had sick or dead birds or other animals, carcasses, feces, or litter from potentially infected birds or other animals. Workers should receive training on and demonstrate an understanding of when to use PPE; what PPE is necessary; how to properly put on, use, take off, dispose of, and maintain PPE; and PPE limitations.

Influenza A detections in U.S. goats

USDA’s National Veterinary Services Laboratories confirmed highly pathogenic avian influenza (HPAI) in neonatal goat kids that demonstrated neurologic signs from a Minnesota backyard premises recently affected with HPAI.

The goats on the premises shared the same pasture and sole water source with infected ducks and chickens. The goats began to kid only days after the birds were depopulated. Of 10 goat kids that have died, ranging from 5 days to 9 days of age, five goat kids between 7 and 9 days of age have tested positive on brain and other tissues for H5N1 clade virus. Sequencing showed that isolates from the first goat and infected poultry were highly related.

For more information  LINK


Influenza A in cats

Testing of sick cats on some affected dairy farms in Texas and Kansas for H5N1 has so far yielded three H5N1 (HPAI) positives. This isn’t the first time the virus has been detected in cats (e.g. they’ve been reported before in the US, Poland, and South Korea) but does suggest they should be kept away from cattle. LINK

Biosecurity resources

Biosecurity Update for On-farm Dairy Service Providers LINK


Dairy Biosecurity Recommendations: HPAI and more LINK


proAction: Canadian Dairy Quality Assurance Program Biosecurity Module LINK


USDA-APHIS Secure Milk Supply (SMS) Dairy Biosecurity Resources LINK


CAHSS Biosecurity Recommendations for Canadian Dairy Herds LINK

Frequently Asked Questions

Canadian Food Inspection Agency: Highly pathogenic avian influenza (HPAI) in livestock LINK


USDA-APHIS: Detection of Highly Pathogenic Avian Influenza in Dairy Herds: Frequently Asked Questions LINK


USDA-APHIS: Questions and Answers Regarding Milk Safety During Highly Pathogenic Avian Influenza (HPAI) Outbreaks   LINK

HPAI issues and commentaries

 As reported by the journal Science, at a joint meeting of WOAH and FAO in which USDA provided situation update on H5N1 outbreaks 4th April:
- USDA reported no real evidence virus is replicating inside the cows aside from the udder
-hypothesis that it may be moving between cattle by indirect contact (e.g. milking equipment) and opposed to, say respiratory route like coughing/fecal shedding.
-also a hypothesis that viruses in all affected US cows to date are so similar that they may have originated from one herd. So potentially what we've seen so far for H5N1 disease in US dairy cows could reflect one spillover event from birds, or a couple of closely related ones, as opposed to multiple independent events in which multiple infected birds contacted multiple herds.


Dr. Scott Weese: Avian Flu in Cattle: What to Be Concerned About and What Not to Freak Out About LINK

Dr. Scott Weese: H5N1 Avian Flu in a Cat on a Dairy Farm (Completely Unsurprising)  LINK