Avian influenza, also known as “bird flu,” occurs naturally among wild birds and waterbirds and can infect domestic poultry, other birds and mammals. One type of avian influenza, a strain called A(H5N1), has recently been detected in dairy cattle in the United States.
Although human infections of A(H5N1) are rare, some workers are at higher risk of being exposed and becoming infected. This includes workers on dairy farms, workers caring for, transporting, and processing cattle, and workers handling or processing raw milk, also referred to as unpasteurized milk. Workers should take additional steps to minimize their risk of exposure to:
Infected or potentially infected dairy cattle
Contaminated environments, such as barns and animal pens
Contaminated equipment, including milking equipment, shovels, vehicles, and other workplace objects
Raw milk
This document provides employers and workers with information on A(H5N1) associated with dairy cattle and recommends additional control measures to minimize the risk of infection.
Symptoms of Avian Influenza A(H5N1)
People
People with A(H5N1) infection may not develop any symptoms, or they may only develop mild ones. However, some infections can lead to severe symptoms and even progress to death. Symptoms of A(H5N1) in people typically occur within one to five days after exposure to the virus, and sometimes longer.
Early symptoms of A(H5N1) infection in people can include:
Tearing, redness, irritation of the eyes, and pink eye, also known as conjunctivitis
Cough
Fever
Shortness of breath
Sore throat
Muscle aches
Headache
Diarrhea
Runny nose
Fatigue
Dairy Cattle
Signs of illness in infected cattle can include:
Decrease in milk production, which is often sudden and significant
Milk with a thicker consistency, similar to colostrum
Low appetite
Decreased feed intake
Decrease in rumination, or swallowing and chewing
Respiratory signs, including clear nasal discharge
Low energy, sluggishness, and lethargy
Dry manure or diarrhea
Dehydration
Fever
Sources of Exposure to A(H5N1) from Dairy Cattle and Transmission to People
Workers are at higher risk of infection when they are exposed to infected dairy cattle or contaminated environments, equipment, objects, secretions, or raw milk. The virus has been found in the raw milk, lungs, muscles, and udder tissues of infected dairy cattle.
You may be exposed to A(H5N1) from dairy cattle when:
Liquids such as raw milk, or droplets contaminated with the live virus, get into your eyes, nose or mouth
Touching an object that is contaminated with the virus and then touching your eyes, nose, or mouth with unwashed hands
Handling or having close contact with infected dairy cattle, including during milking
Handling organs or other animal tissues, including lungs, muscles, other organs and soft tissues, and udders from infected dairy cattle carcasses
Dairy industry jobs that may have exposures to A(H5N1) include, but are not limited to:
Farmer
On-farm labourer
Artificial insemination technician
Farrier or hoof trimmer
Milking operator
Veterinarian and veterinary staff
Bulk milk grader
Dairy plant process worker
Transport vehicle operator
Equipment specialist
Plant grader
Laboratory worker testing raw milk
Slaughterhouse worker
Deadstock transporter
Rendering plant worker
Each workplace is unique, and employers must take every reasonable precaution to protect workers. In workplaces where workers may have been exposed to A(H5N1), a risk assessment must be conducted, and the employer must use additional control measures. A risk checklist can help identify risks and control measures.
Workplace Control Measures
After identifying the risks to workers, employers must use the most appropriate control measures, keeping in mind the hierarchy of controls. It is recommended to take a layered approach, where multiple control measures applied at the same time are more effective than a single control measure.
In addition to specific biosecurity control measures, consider additional control measures when working directly or in close contact with dairy cattle or environments and materials that are known or suspected to be infected with A(H5N1):
Take appropriate precautionary measures and reduce contact whenever possible with:
Raw milk
Sick or infected dairy cattle
Carcasses from dairy cattle that have died, particularly from unknown reasons
Viscera and udders from lactating dairy cattle
Objects that may be contaminated with the virus, for example, buckets or equipment
Whenever possible, always work in well-ventilated environments or outdoors
Regularly wash hands with soap and water. If soap and water are not available, use hand sanitizer containing at least 60% alcohol
Avoid touching the eyes, nose, or mouth with unwashed hands
Clean and disinfect high-risk areas regularly, such as isolation and calving pens, milking parlours, and water and feed areas
Clean and disinfect vehicles and equipment before and after use
Establish work practices and controlled access zones to avoid potential cross-contamination by keeping vehicles away from high-risk areas
Do not eat, drink or smoke in areas where dairy cattle are kept
Use dedicated clothing and footwear when working on the farm, or appropriate disposable coveralls and boot covers, and safely discard them before leaving the farm
Wash and change all clothes and shower after work
Isolate sick cattle from the rest of the herd
Practice good biosecurity measures as outlined in the National Biosecurity Standards and follow the Dairy Farmers of Canada’s proAction program, if applicable
If workers cannot avoid direct or close contact with dairy cattle, carcasses or environments, equipment, materials and animal products, including raw milk, that are known to be or are potentially contaminated with A(H5N1), the following personal protective equipment is recommended:
Waterproof gloves, including PVC, nitrile, chloroprene, or rubber gloves
Safety goggles or face shields if there is a risk of splashing liquid
Suitable masks, preferably a fit-tested N95 respirator
Fluid-resistant coveralls
Waterproof aprons
Rubber boots or boot covers
Head or hair covers
Follow proper procedures for putting on and taking off personal protective equipment:
Clean and disinfect reusable personal protective equipment.
Safely discard disposable personal protective equipment in a sealed plastic bag.
Emergency Preparedness and Response Plan
An emergency preparedness and response plan is useful in workplaces where avian influenza infection is a possible threat. This plan should outline how to prevent, detect, and respond to sick workers. It can be written as a policy and procedure.
While an avian flu vaccine is not currently available in Canada for public use at this time, the seasonal influenza vaccine can help reduce the chances of having both avian flu and seasonal flu at the same time and more severe illness.
Workers who become sick should be encouraged to take time away from work. A sick leave policy can support this time off. They should also isolate themselves from others, follow measures to reduce the spread of respiratory viruses and seek medical attention, including getting tested to confirm or rule out avian influenza.
Individuals who work while sick are a risk to other workers. While person-to-person transmission of A(H5N1) is very rare, the risk may change if the virus changes. Additionally, sick workers may feel worse over time and can present a hazard to others if they are unable to work safely.
If human illness is suspected, clean and disinfect areas, tools, equipment, and other objects that may be contaminated. If the illness happened at work, conduct an incident investigation to determine the cause and help prevent recurrence or spread among workers.
If a worker develops life-threatening symptoms, call 911 for medical assistance. Inform their emergency contact and report the incident to external regulators, health and safety committees, local public health authorities, and other relevant parties.
Reporting and Support
Workers exposed to the A(H5N1) virus may become ill, need time off work, or require medical attention. Any workers experiencing illness, even mild symptoms, after exposure to suspected or confirmed sources of A(H5N1) should contact their employer, healthcare professional, or local public health authority.
Contacting the relevant public health authority will ensure timely testing and reporting of human illness to the Public Health Agency of Canada (PHAC), initiating an epidemiological investigation, and taking steps to help prevent further illness. Inform the government department responsible for occupational health and safety and the workers' compensation board if the reporting requirements for your jurisdiction have been met.
Highly pathogenic avian influenza of any subtype in any animal species should be reported to the Canadian Food Inspection Agency (CFIA). If dairy cattle or any other livestock being cared for or controlled by the workplace is suspected of having avian influenza, contact your veterinarian or your local CFIA district office.
Becoming ill with avian influenza can impact workers’ mental health and may lead to increased stress, anxiety and depression. Mental health resources and support should be provided to all workers, including access to an employee assistance program if available.
Refer to the following mental health information resources:
Disclaimer: Although every effort is made to ensure the accuracy, currency, and completeness of the information, CCOHS does not guarantee, warrant, represent or undertake that the information provided is correct, accurate or current. CCOHS is not liable for any loss, claim, or demand arising directly or indirectly from any use or reliance upon the information.
