Avian influenza in dairy cows

Since spring 2024, in the United States, the H5N1 virus has been detected in several herds of dairy cows. A herd of goats and a herd of alpacas have also been infected. This virus is highly pathogenic for poultry, meaning they can become seriously ill or die if they contract it. It does not currently cause any serious illness in other livestock or humans. That could change in the future, however, so animal health and public health authorities are monitoring the situation closely.

The Québec government has worked closely with industry stakeholders and the federal government to develop and implement the Québec public health monitoring, prevention, control and protection strategy for highly pathogenic avian influenza in dairy cows (PDF 773 Kb) [French only].

Cows with avian influenza show various symptoms. One symptom is eating less than usual. Dairy cows produce less milk and that milk is thicker. Sick cattle appear tired and may have a fever. They may have tacky stool or diarrhea.

Some infected cows do not show any symptoms.

In the recent H5N1 cases in the United States, the virus may have first been transmitted from wild birds to a cow, which then transmitted it to other cows. Transmission between dairy cattle often occurred after an infected cow, with or without symptoms, was introduced to a herd.

The exact way in which the virus spreads between cows has yet to be clearly identified. However, the udder and milk of infected cows contain high levels of the virus. Raw milk containing H5N1 can infect animals that drink it or other cows that come in contact with it on milking equipment and milkers’ hands. On affected dairy farms, cats were infected with H5N1 virus after drinking contaminated raw milk.

On farms, goats that shared an environment with poultry with avian influenza were also infected. The virus also affected alpacas that were introduced to a farm where poultry with avian influenza had been euthanized a few weeks earlier.

The risk to the general public of infection from poultry remains low. To learn more about transmission of avian influenza from birds to people, visit the Avian influenza page.

The risk of infection from livestock is very low.

The risk is slightly higher for individuals with more exposure to poultry and livestock, such as people working with these animals. Transmission of avian influenza to humans has generally resulted from close contact with infected animals in farms or slaughterhouses.

Proper personal protection measures include wearing clean clothes and boots on the farm, as well as changing them and then washing your hands after leaving a building. If you have a wound on your hand, bandage it and wear gloves while on the farm.

The recent human cases identified in the United States were among people working on a dairy farm impacted by H5N1. Infected individuals exhibited signs of conjunctivitis and symptoms of influenza-like illness. These are the first cases in the world of avian influenza being transmitted from a mammal to a person.

Sick cows sometimes require supportive treatment to lower a fever or rehydrate. However, there is no specific treatment for H5N1 virus in animals. Sick cows recover after a period of 10 to 14 days. So far, there have been no H5N1-related deaths in infected livestock.

Apply farm biosecurity measures [French only] in all livestock sectors to reduce the risk of avian influenza virus spreading to cattle, goats, pigs, alpacas and other livestock.

Try to avoid introducing dairy cattle from regions with confirmed cases of avian influenza. If cattle must be introduced into a dairy herd, follow the usual buying protocol recommendations. Due to the outbreak of avian influenza in US dairy cattle, the Canadian Food Inspection Agency (CFIA) has changed its requirements for importing live cattle from the United States. US dairy cattle must now be tested for avian influenza before they can be imported.

Gatherings of animals, like expos, competitions, fairs and small farms, are environments favourable to the transmission of H5N1 avian influenza. Before taking part, read about the necessary precautions in the Notice to organizers of gatherings of animals and to participating animal owners (PDF 206 Kb) [French only]. In addition, the Ministère de l'Agriculture, des Pêcheries et de l'Alimentation advises against Québec dairy farmers participating in expos outside the province, particularly in the United States, due to the increased risk of transmission of the H5N1 virus currently circulating in the US dairy cattle population. If you choose to travel with your animals to the US despite this risk, control measures will be required by the CFIA upon your return.

Keep livestock away from commercial farm poultry, backyard flocks and wild birds. Québec has regulations on keeping different species of animal in a single agricultural building. For example, it is illegal to keep poultry in a dairy barn.

Animals that are suspected or confirmed to be sick must be isolated. No animals should enter or leave a farm during a quarantine period.

Sick animals should be milked last. The milk should be discarded, and the milking equipment cleaned and disinfected. Keep potentially contaminated raw milk from coming into contact with other animals such as cats, which may try to drink it.

If your herd is infected, contact animal and public health authorities, who can help you identify what measures you need to apply.

Animal owners should be aware at all times of the health of their animals and should contact a veterinarian in case of illness. Veterinarians in all industries must stay alert for avian influenza, and should call 1-844-ANIMAUX and their local Canadian Food inspection Agency office if they suspect an animal of having avian influenza. Highly pathogenic and low pathogenic avian flu (subtypes H5 and H7) is a reportable disease.

Avian influenza is not a food safety issue. Available dairy products are safe for Québec consumers.

The usual safe food handling practices, such as cooking, pasteurization and prevention of cross-contamination, are also appropriate for avian influenza. Follow these recommendations to prevent food poisoning.

Pasteurization is a process that destroys bacteria and harmful viruses, including avian influenza.

All dairy products sold in Québec must be pasteurized, with the exception of certain cheeses made with unpasteurized milk.

Cheeses made from unpasteurized milk are still processed to reduce the risks associated with viruses and bacteria that may be present in raw milk. There is also a monitoring system to ensure that these cheeses are not made with contaminated milk or milk from sick animals.

Some people are more susceptible to foodborne illnesses. People with a weakened immune system, pregnant women, young children and the elderly should avoid eating cheese made from unpasteurized milk at all times.

The sale of raw (unpasteurized) milk is strictly prohibited in Québec. Only pasteurized milk can be sold and consumed safely. Dairy farmers and their families, who can access raw milk on farms, should be aware that the consumption of raw milk, which carries a heightened risk of serious food poisoning, is strongly discouraged.

Prepare and cook beef properly to ensure it is safe to eat.