Bird Flu (Avian Influenza)

What is bird flu?

Bird flu (avian influenza) is an infection from a type of influenza (flu) virus that usually spreads in birds and other animals. Sometimes, humans can get bird flu from infected animals. Like the versions of flu that people usually get, bird flu can make you severely ill. It’s extremely rare for it to spread from person to person.

You might hear about bird flu when there’s an outbreak affecting large numbers of birds or other animals. This is concerning because it increases the risk of human infection, can affect wildlife and can reduce the food supply. There have been ongoing cases of human infections in the U.S. since 2024.

Types of bird flu

There are many subtypes of avian flu. The recent cases in humans in the U.S. are influenza A(H5). The most common subtypes that have spread to humans in the past have been influenza A(H5N1) and influenza A(H7N9). The types of proteins on the surface of the virus determine the names of these subtypes.

What are the symptoms of bird flu (avian influenza)?

Symptoms of bird flu include:

• Pink eye (conjunctivitis)
• Fever
• Fatigue
• Cough
• Muscle aches
• Sore throat
• Nausea and vomiting
• Diarrhea
• Stuffy or runny nose
• Shortness of breath (dyspnea)

These symptoms can be mild or severe. Most recent cases of bird flu in the U.S. have caused pink eye and mild respiratory symptoms.

What causes bird flu?

A type of influenza A virus, often H5N1 in humans, causes bird flu. The virus can infect your upper respiratory tract and lungs, and sometimes spread to other parts of your body like your brain.

How does bird flu spread?

Humans can get bird flu if they come in contact with an infected animal’s body fluid, like spit (saliva), milk, respiratory droplets or poop (feces). You can breathe it in from small dust particles in animal habitats or get it into your eyes, nose or mouth after touching body fluids.

You don’t get bird flu from eating properly cooked poultry or eggs or from drinking pasteurized milk. Any flocks known to have avian flu virus are immediately taken out of the human food supply.

Is bird flu contagious?

Bird flu is very rarely contagious (spread from person to person), but there have been a few cases of spread between humans. None of these happened in the U.S. In almost all cases so far, human bird flu infections have come from contact with infected animals. But any time a human is infected, it’s possible that the virus could mutate to spread easily to other humans.

What are the risk factors for bird flu?

People who work with poultry, waterfowl (like ducks or geese) and dairy cows are at the highest risk for bird flu.

What are the complications of bird flu?

Bird flu can often cause severe illness. Complications include:

• Pneumonia
• Acute respiratory distress
• Bacterial infections
• Sepsis
• Brain swelling, like meningoencephalitis
• Respiratory failure

How is bird flu diagnosed?

Healthcare providers can diagnose avian flu with a throat or nose swab or a swab from the conjunctiva of your eye. Current tests will detect highly pathogenic H5N1 (bird flu) as influenza A. Labs don’t routinely test all positive influenza A swabs for avian flu, so you have to let your provider know that you’ve been in contact with birds, cows or other animals that could be infected. Then, if the test is positive for influenza A, the lab will send the sample to a special lab to be tested for bird flu.

How is bird flu treated?

If identified early, you can treat bird flu with antiviral medications. A provider might prescribe:

• Oseltamivir (Tamiflu®)
• Peramivir (Rapivab®)
• Zanamivir (Relenza®)

How can I prevent bird flu?

Ways to reduce your risk of bird flu include:

• Wear protective clothing — like gloves, a mask and goggles — when working with birds, wild animals and livestock
• Wash your hands frequently when handling birds, wild animals and livestock or after being in areas where they live. This includes visiting petting zoos, farms or areas with water features that geese or ducks frequent.
• Don’t work with animals who are sick or who’ve been exposed to avian influenza. In case of an outbreak, follow public health guidelines to limit the spread.
• Take your shoes off before entering your home if you’ve been in areas where birds like waterfowl or chickens live. This reduces the risk of spreading bird droppings (or anything else that could be contaminated with the virus) around your house.
• Don’t touch or drink unpasteurized milk.
• Get a seasonal flu shot. This won’t directly protect you from bird flu, but it can reduce your risk of serious illness and of getting both avian influenza and seasonal influenza at the same time (coinfection).

Public health authorities — like the Centers for Disease Control and Prevention (CDC) in the U.S. — monitor cases of bird flu in animals and people to try to reduce the risk of spread. Scientists are working to develop vaccines that could help prevent avian flu or reduce its severity. These could be put into use if there were a risk of a large outbreak.

What can I expect if I have bird flu?

Some people with bird flu only have mild symptoms, or even no symptoms at all. If you get severely ill, you’ll need to stay in the hospital so a healthcare team can monitor your symptoms and treat you for complications right away.

What’s the mortality rate of bird flu?

Overall, the mortality (death) rate for bird flu in humans is high — historically, about half of all people with known infections have died. But most recent cases in the U.S. have been mild.

When should I see my healthcare provider?

If you’re at a higher risk for avian influenza, talk to your provider about prevention and when you should seek care if you have symptoms. See a provider if you think you’ve been exposed to bird flu.

When should I go to the ER?

Go to the nearest emergency room if you have symptoms of severe illness, including:

• Difficulty breathing
• Fever over 103 degrees Fahrenheit (40 degrees Celsius)
• Confusion or altered mental state
• Severe fatigue or inability to wake up
• Severe headache
• Stiff neck

What questions should I ask my healthcare provider?

It might be helpful to ask your provider:

• What treatments are available?
• What severe symptoms should I look out for?
• How can I prevent spreading bird flu to others?

Is bird flu a problem now?

Bird flu spreads in birds, cows and other mammals. It sometimes spreads from animals to people. This is a problem for wildlife health, food supply and human health.

Can bird flu cause a pandemic?

It’s possible. If a version of bird flu had a gene mutation that allowed it to spread easily between people, it could cause a pandemic.

How do cattle get bird flu?

Cattle and other animals get bird flu in the same way that humans can get it — through breathing in the virus from contaminated dust in animal habitats or direct contact with body fluids of infected animals.