Bird flu, also known as avian influenza, is an infectious disease caused by a virus that mainly affects birds but can also infect humans. The disease comes from influenza A viruses, which have several subtypes. The subtypes fall into categories based on the protein composition on the virus's surface, namely, hemagglutinin (H) and neuraminidase (N) as seen in names such as H5N1 and H7N9.
How Bird Flu Spreads
All flu viruses can infect multiple species, including ducks, chickens, pigs, cows, horses and seals. Bird flu refers to a specific Type A flu virus, H5N1, which currently spreads easily among birds, but can sometimes spread to other animals and humans. Bird flu has been found in dairy cattle in the U.S.
It's important to note that — while bird flu can lead to severe respiratory (breathing) symptoms in humans — it’s rare for bird flu to spread human-to-human. The disease most often spreads to humans through direct and prolonged contact with infected birds or bird secretions (bird saliva, nasal secretions and feces). This puts people who work with live poultry at higher risk. Transmission is likely related to someone touching an infected animal and then touching their face or eyes. Careful handwashing after contact with animals is extremely important.
The virus can survive in the environment — especially in water and on surfaces — for long periods. This allows it to spread more easily among birds that gather in close quarters, such as at poultry farms or live bird markets. Migratory birds play a significant role in spreading the virus during seasonal migration, introducing it to areas that have not been affected by the virus before.
Symptoms of Bird Flu
Bird flu symptoms in humans are similar to a mild upper respiratory infection or a common cold. Symptoms include:
- Low-grade fever
- Sore throat
- Muscle aches
- Pink eye
- Cough
Rarely, these symptoms get worse fast, leading to serious complications such as pneumonia and sudden, severe breathing problems, also known as acute respiratory distress. Tell your doctor if you have a history of being around birds or poultry. Seeing a doctor to determine if you have bird flu and isolating if you do is essential for appropriate treatment and to avoid spreading the virus.
Bird Flu Treatment
Antiviral medications such as oseltamivir (Tamiflu) and zanamivir (Relenza) are the primary treatments for bird flu in humans. Taking these drugs early in the course of your illness can help reduce how long you are sick and how severe your symptoms are. A virus can develop resistance to antivirals, making the drugs ineffective.
If you have a severe case of bird flu, you may need to be in the hospital to receive fluids and oxygen to manage complications like severe pneumonia or acute respiratory distress syndrome.
Preventing the Spread of Bird Flu
Using effective ways to prevent and control bird flu is critical to limit the spread of the disease among birds and humans. Strict biosecurity procedures at poultry farms are essential for controlling the movement of birds and improving sanitation practices. The goal is to reduce direct contact between birds and humans and to limit the ways the virus can spread.
Vaccinating poultry is another important strategy, especially in regions with known infections, as it helps contain bird flu outbreaks by building immunity within the flock. Public health campaigns also play a vital role in educating the public and poultry workers about the importance of early detection and rapid reporting of symptoms in birds. Ongoing surveillance systems give us an early warning about new outbreaks, allowing us to respond quickly and contain potential epidemics.
Bird flu is not limited to poultry such as chickens and ducks; it also affects a variety of wild bird species, including sparrows, owls, and geese. Hunters and birdwatchers who frequently come in contact with wild birds are at an increased risk of exposure. If you must handle a wild bird, whether alive or dead, wearing protective gloves is crucial to prevent direct skin contact and potential infection. After handling, wash your hands thoroughly with soap and water to remove any traces of the virus.
Research is ongoing to develop vaccines for humans that can offer a stronger defense against bird flu. Developing a vaccine is challenging due to the virus's ability to change, requiring constant updates to vaccine formulations.
Additional Bird Flu FAQ
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Are eggs safe to eat if there is bird flu?
The risk of getting sick from eggs is very low. Cooking eggs thoroughly kills any viruses or bacteria that might be present. The U.S. food safety system also makes sure that eggs from sick birds do not enter the food supply. Farmers work hard to keep their chickens healthy by following strict rules to prevent the spread of bird flu. As long as people cook eggs properly — until both the yolk and white are firm — there is no danger from bird flu.
For more information, read the "Food Safety and Avian Influenza Q&A" from the U.S. Department of Agriculture.
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Is chicken safe to eat if there is bird flu?
Cooking chicken properly kills the virus. The bird flu virus cannot survive high temperatures, so when chicken is cooked to an internal temperature of 165°F (75°C), it becomes safe to eat. Also, strict food safety rules make sure that sick birds do not enter the food supply. Farmers and food inspectors work hard to prevent the spread of bird flu and keep chicken meat safe.
Learn more about safe food handling at fsis.usda.gov.
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Can I get bird flu from milk?
Milk from healthy, properly raised dairy animals does not carry bird flu. Additionally, pasteurization — used in commercial milk production — kills viruses and bacteria, making milk safe to drink. Consuming raw (unpasteurized) milk, however, carries risks of other infections, so it's always best to choose pasteurized dairy products.
Learn more about food safety and bird flu from the Centers for Disease Control.
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What is it like to recover from bird flu?
Recovering from bird flu depends on the severity of the infection. In mild cases, symptoms may be similar to regular flu—fever, cough, sore throat and muscle aches—resolving in about a week with rest and supportive care.
For more severe cases, recovery can be long and difficult. Some people develop complications like pneumonia, acute respiratory distress syndrome (ARDS), or organ failure, requiring hospitalization. Recovery in these cases may take weeks or even months, often involving breathing support, antiviral medications (like oseltamivir or zanamivir) and rehabilitation for lung and muscle function.
After a severe infection, lingering fatigue, lung damage and weakness are common. Some patients also experience mental fog or psychological effects due to prolonged illness. Full recovery depends on overall health, age and how early treatment began.
