Medical Health Cluster

28 mayo, 2024

Bird Flu (Avian Influenza)

Avian influenza, commonly called “bird flu,” is a viral infection that usually spreads in birds but can sometimes spread to humans. Influenza A(H5N1) is the most common cause in humans. It can cause severe respiratory symptoms. People who work with poultry, waterfowl (like geese and ducks) and livestock are most at risk.


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 be serious and is much more likely to be deadly. 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.

Types of bird flu

There are many subtypes of avian flu. The most common subtypes that spread to humans are influenza A(H5N1) and influenza A(H7N9). These are named based on types of proteins on the surface of the virus.

How common is bird flu in humans?

So far, bird flu infections in humans are rare. There have been less than 1,000 known cases worldwide since it was first identified in humans in 1997. There have only been two cases in the U.S.

Symptoms and Causes

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

Symptoms of bird flu include:

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

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 even 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), 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. 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.

What are the risk factors for bird flu?

People who work with poultry or waterfowl (like ducks or geese) are at the highest risk for bird flu. You also may be at risk if you work with livestock.

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.

Diagnosis and Tests

How is bird flu diagnosed?

Healthcare providers can diagnose avian flu with a throat or nose swab. They don’t routinely test for avian flu, so you have to let them know that you’ve been in contact with birds or other animals that could be infected. They’ll have to send the sample to a special lab to be tested.

Management and Treatment

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’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 after being 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.

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. They have vaccines for avian flu that could quickly be put into use if there were a risk of an outbreak.

Outlook / Prognosis

What can I expect if I have bird flu?

Some people with bird flu only have mild symptoms, or even no symptoms at all. But many people get severely ill. You may 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?

The mortality (death) rate for bird flu in humans is high — over 50% for all known cases worldwide. This means half of all people diagnosed with bird flu die from it.

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?

Additional Common Questions

Is bird flu a problem now?

Bird flu continues to spread in birds around the world. This is a problem for wildlife health, food supply and human health. Cases in people sometimes happen.

Can bird flu cause a pandemic?

It’s not likely, but 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.

A note from Cleveland Clinic

You might be alarmed when you see headlines about bird flu. But while it’s important to protect yourself if you’re around birds or other animals that carry it, it rarely spreads to humans. Public health officials monitor cases and have a vaccine ready if it becomes a high risk to humans. Talk to a healthcare provider if you have concerns about your risk for bird flu.

Bird flu symptoms include fever, sore throat, cough, stuffy or runny nose, fatigue, muscle aches, digestive issues and more.
Bird flu symptoms are sometimes mild, but many people develop severe respiratory complications.




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