Avian influenza A viruses may be spread from infected birds to other animals, and potentially to humans, in two main ways:

• Directly from infected birds or from avian influenza A virus-contaminated environments.
• Through an intermediate host, such as another animal.

Though unlikely, it is possible for the H5N1 virus to be transmitted to humans. Infection can occur through exposure to the saliva, mucus, or feces of infected birds, or their environments if a sufficient amount of the virus enters the eyes, nose, or mouth, or is inhaled by humans.

Individuals with close, prolonged, unprotected contact (not wearing recommended personal protective equipment (PPE)) with infected birds or other animals or surfaces that infected animals have contaminated with their secretions/excretions like mucous, saliva, feces, or milk (in dairy cows) are at greater risk of infection.

People with job-related or recreational exposures to birds or other H5N1-infected animals are at greater risk of infection.

These workers are currently most likely to be exposed:

• Poultry and dairy and other livestock farmers and workers
• Other livestock workers
• Backyard bird flock owners
• Veterinarians and veterinary staff
• Animal health responders
• Public health responders
• Dairy laboratory workers
• Food processing workers handling raw milk and other confirmed or potentially contaminated materials
• Slaughterhouse workers performing certain tasks on lactating dairy cattle, including:
  • Unloading or handling live lactating dairy cattle for slaughter, including working in holding pens and tasks involved with ante-mortem inspection
  • Post-mortem processes including the post-mortem inspection, handling, and transporting of viscera
  • Removing and transporting udders from dairy cattle for further processing or rendering
• Zoo or other wild animal facility workers, such as:
  • Sanctuary workers
  • Aquarium workers
  • Wild animal rehabilitation center workers
• Hunters

People with job-related or recreational exposures to birds or infected mammals should take appropriate precautions to protect against bird flu. For more information on how to stay healthy around backyard poultry is available at Backyard Poultry | Healthy Pets, Healthy People | CDC.

The reported signs and symptoms of H5N1 virus infections in humans have ranged from no symptoms or mild symptoms to moderate to severe disease and complications, including resulting in death.

Mild Signs and Symptoms

• Eye redness and irritation (conjunctivitis)
• Mild fever (temperature of 100ºF [37.8ºC] or greater) or feeling feverish*
• Cough
• Sore throat
• Runny or stuff nose
• Muscle or body aches
• Headaches
• Fatigue

Eye redness has been the predominant symptom among recent U.S. cases of H5N1 virus infection. Less common symptoms include diarrhea, nausea, or vomiting.
*Fever may not always be present

Moderate to Severe Signs and Symptoms

• High fever
• Shortness of breath or difficulty breathing
• Altered consciousness
• Seizures

More information about symptoms of H5N1 virus infections in people, including timing of symptoms, and complications, is available at Signs and Symptoms of Bird Flu in People.

The best way to prevent bird flu is to avoid sources of exposure whenever possible. People should avoid direct contact with sick or dead wild birds, poultry, and other animals and observe them only from a distance. If you must have direct/close contact with sick or dead wild birds, poultry, or other animals, including dairy cows, wear recommended PPE.

• Do not touch surfaces or materials (e.g., animal litter or bedding material) contaminated with saliva, mucous, or animal feces from birds or other animals with confirmed or suspected avian influenza A virus infection.
  
  
• Do not touch or consume raw milk or raw milk products, especially from animals with confirmed or suspected avian influenza A virus infection. Choosing pasteurized milk and products made with pasteurized milk is the best way to keep you and your family safe. Pasteurization kills bacteria and viruses, like avian influenza A viruses, in milk.
  
  
  
• Cook poultry, eggs, and beef to a safe internal temperature to kill bacteria and viruses. More information about safe handling and cooking of poultry is available at Chicken and Food Poisoning. Refer to CDC's safer foods table for a complete list of safe internal temperatures.

While it is unlikely that coming into contact with dead birds will cause human infections, it's wise to take precautions to minimize the risk of spreading H5N1.

Disposal

Practice universal precautions when handling a deceased bird. Make sure to use appropriate personal protective equipment, which includes:

• Disposable waterproof gloves
• Plastic bags
• Safety goggles
• N95 mask
• Trash can with a secure lid

Follow these steps:

1. Utilize safety goggles and an N95 mask to safeguard your eyes, nose, and mouth, when possible.
2. Use disposable waterproof gloves and/or an inverted plastic bag to lift dead bird(s).
3. Double-bag the bird(s) securely and dispose of them in a trash can inaccessible to children or animals.
4. After handling a bird, refrain from touching your face with gloves or unwashed hands.
5. Wash your hands thoroughly with soap and water. If soap and water are unavailable, use hand sanitizer.
6. Launder your clothes in a washing machine using detergent and the hot water cycle.
7. To minimize the risk of infection to other animals, keep dogs and other pets away from the carcasses of birds that may have succumbed to H5N1.
8. If you find 5 or more deceased birds, inform the Illinois Department of Natural Resources (IDNR).

Additional Steps:

• Regular handwashing
• Avoiding contact with sick or dead birds
• Follow local health guidelines

The primary risk factor for contracting bird flu is exposure to infected, sick, or dead animals. Additional risks include contact with surfaces contaminated by secretions or excretions (such as saliva, mucus, feces, or milk) from infected animals.

Consuming undercooked or raw poultry, eggs, or unpasteurized milk from infected animals may also lead to infection. Properly cooked or pasteurized products, however, are safe to consume.

To reduce exposure risks:

• Avoid handling sick or dead animals.
• Use protective measures, such as personal protective equipment (PPE), when contact with animals or contaminated environments is unavoidable.
• Ensure that poultry, eggs, and beef are thoroughly cooked to a safe internal temperature.
• Choose pasteurized milk and dairy products to eliminate the risk of contamination.

Testing & Diagnosis 

There are tests that can detect avian influenza virus infections. People with recent exposure to infected (or suspected to be infected) birds, animals, or their byproducts and who have symptoms, can be tested. Reach out to your health care provider and your local public health department to be tested. People who do not have symptoms, but who had a higher risk exposure to infected animals or by-products may also be offered testing by their state or local health department as part of ongoing public health investigations.

Treatment
Flu antiviral drugs can treat avian influenza A virus infections. People who develop bird flu symptoms following exposure to infected animals should receive treatment with flu antivirals (oseltamivir) as soon as possible.

Also, people who had exposure to infected animals who did not wear the recommended personal protective equipment (PPE) or who had a breach in their PPE, may be offered flu antivirals, regardless of whether they have symptoms or not.

Antiviral treatment works best within 48 hours of developing symptoms. Antiviral treatment should not be delayed while waiting for testing results.

H5 bird flu is widespread in wild birds worldwide and is being reported in an increasing number of animals worldwide in addition to outbreaks in poultry and U.S. dairy herds.

Wild birds that can carry avian influenza viruses include waterbirds, like ducks, geese and swans, and shorebirds, like storks. While most wild birds can be infected with avian influenza A viruses without being sick, poultry, like chickens and turkeys, can get infected and get very sick and die from certain avian influenza viruses. Most common songbirds or other birds found in the yard, like cardinals, robins, sparrows, blue jays, crows or pigeons, do not get infected with avian influenza viruses.

The Illinois Department of Natural Resources (IDNR) advises avoiding contact with wild birds, especially waterfowl, and reporting any unusual bird deaths. Residents should never touch dead or visibly ill birds without proper protective measures, including gloves and masks. Keep dogs and other pets away from carcasses of birds that may have died. Any contact should be followed by thorough handwashing and sanitization of surfaces. For more information and how to report concentrations of five or more deceased birds found at one location, visit IDNR.

Other mammals also can be infected with avian influenza A viruses. In these animals, signs can range from mild to severe, including death. In addition to dairy cows, H5N1 has been detected in other mammals. Information about recent detections of bird flu in animals is available at 2022–2024 Detections of Highly Pathogenic Avian Influenza.

• The current public health risk of H5N1 remains low. 
• To help prevent the spread of H5N1, utilize personnel protective equipment (PPE) when working around high-risk animals or when handling dead animals.
• If an individual becomes symptomatic after exposure to a possible infected animal, testing and treatment with antivirals should not be delayed.
• Ensure all meat and poultry are cooked to proper temperatures, and avoid consuming unpasteurized or raw dairy products.

H5N1 Technical Report | Bird Flu | CDC

Avian Influenza (Bird Flu) Resources | Bird Flu | CDC

H5 Bird Flu: Current Situation | Bird Flu | CDC

News & Spotlights | Bird Flu | CDC

Highly Pathogenic Avian Influenza A(H5N1) Virus: Interim Recommendations for Prevention, Monitoring, and Public Health Investigations | Bird Flu | CDC

To protect workers who might be exposed, employers should update or develop a workplace health and safety plan. Employers are encouraged to use a health and safety committee that includes representatives from both management and workers to develop the plan. Helpful guidance and consultation on developing a workplace health and safety plan is available from the Occupational Safety and Health Administration (OSHA) and through your local agriculture extension office. Employers in a state regulated by a state OSHA plan should familiarize themselves with any additional requirements that may apply to them. Employers should conduct a site-specific hazard assessment to identify potential exposures based on work tasks and locations and use the hierarchy of controls to identify controls to reduce or eliminate hazards including exposure to novel influenza A viruses. The Hazard Assessment Worksheet for Dairy Facilities can help identify dairy workplace hazards and prioritize controls including personal protective equipment (PPE) needed for protection. Protecting Poultry Workers from Avian Influenza (Bird Flu) can help identify poultry workplace hazards and prioritize controls. CDC provides separate recommendations to prevent the spread of flu between pigs and people.

The hierarchy of controls identifies a preferred order of actions to best control hazardous workplace exposures. Engineering controls are more effective than administrative controls or PPE because they control exposures without requiring significant and ongoing efforts by workers and their supervisors. The following table identifies the type of controls that can be used based on our current understanding of the exposure risk associated with different work tasks and settings.

*This is in addition to standard operating procedures for these settings

†Once a positive test result is detected on a poultry farm, all the birds on that farm are considered potentially infected

‡CDC recommends using the USDA-defined control area (10 km or ~6.21 mile radius around a farm) as the region. Factors that may justify widening a region include: (1) worker commute distances greater than 10 km from their home or other workplaces, especially other farms, (2) joint services that serve the farm (such as veterinary services, milk haulers, feed supply, and transport companies), (3) other considerations in the USDA Highly Pathogenic Avian Influenza Response Plan (The Red Book)

To help employers implement the guidance, CDC is providing the following resources:

• Engineering controls to reduce exposure to novel influenza A viruses
• Administrative controls to reduce exposure to novel influenza A viruses
• Personal protective equipment to reduce exposure to novel influenza A viruses
  • Recommended PPE to protect against novel influenza A viruses in high exposure settings
  • Recommended PPE to protect against novel influenza A viruses in medium exposure settings
• Toolbox Talk – Personal Protective Equipment for H5N1 Bird Flu (Spanish)
• Information for employers providing personal protective equipment to reduce exposure to novel influenza A viruses
  • Personal protective equipment specifications to reduce exposure to novel influenza A viruses
  • Information on working in hot environments