Avian Influenza (Bird Flu)

Condition Basics

What is bird flu?

Bird flu is an infection caused by a certain kind of avian influenza virus. Although there are many kinds of bird flu, the most common kinds that concern health workers are H5N1 and H7N9 bird flu viruses. These viruses are found in wild birds. Most of the time, wild birds don't get sick from the virus. But wild birds can easily pass the virus to birds that are being raised for food, such as chickens, ducks, and turkeys. The virus can cause them to get very sick.

Usually bird flu virus is not passed from birds to people. But since 1997, some people have become sick with this serious, deadly kind of bird flu. Most of these infections have been in Asian countries among people who have had close contact with birds raised on farms.

How is it spread?

Bird flu is caused by a virus. After a wild bird infects a farm-raised bird, the virus can easily and quickly spread among hundreds or thousands of birds. Sick birds must then be killed to stop the virus from spreading.

People who come into contact with sick chickens, ducks, or turkeys are more likely to get the virus. Bird flu virus can be passed through bird droppings and saliva on surfaces such as cages, tractors, and other farm equipment.

Most people don't need to worry about getting sick with bird flu virus. You cannot get bird flu from eating fully cooked chicken, turkey, or duck, because heat kills the virus.

In a few cases, bird flu was passed from one person to another person, not from a bird to a person. But this was very rare.

What happens

The bird flu virus can make people sicker than other kinds of flu viruses. Even though only a few hundred people are known to have been sick with bird flu, more than half of them have died.

Experts worry because the bird flu virus is so different from other flu viruses that our bodies do not have immunity against it. Not having immunity means that our bodies have a hard time fighting the virus. It also means that anyone, including those who are otherwise very healthy, can get seriously ill if they get bird flu.

What are the symptoms of bird flu?

At first, the symptoms of bird flu can be the same as common flu symptoms, such as:

• A fever.
• A cough.
• A sore throat.
• Muscle aches.

Sometimes bird flu also can cause other symptoms, such as:

• Vomiting or diarrhea.
• An eye infection (conjunctivitis).

Bird flu can quickly progress to pneumonia and acute respiratory distress syndrome, a serious lung problem that can be deadly.

How is it diagnosed?

If your doctor thinks that you may have bird flu, your doctor will do a physical exam and ask you questions about your symptoms and past health. Your doctor will also ask where you live, where you have traveled recently, and if you have been near any birds. Then your doctor may order blood tests, nasal swabs, or other tests, such as X-rays, to help find out what is making you sick.

How is bird flu treated?

How bird flu is treated depends on what the virus is doing to your body. In some cases, antiviral medicines may help you feel better. But experts are concerned that certain antiviral medicines may not work against bird flu.

If you have bird flu, you will stay in a private hospital room (isolation room) to reduce the chances of spreading the virus to others. When your doctors and nurses are caring for you, they will wear gloves and gowns. Some people who have bird flu may need a machine called a ventilator to help them breathe better. Other people may need a machine to help the kidneys work better (dialysis).

Where can you find the latest information?

These organizations are studying and keeping track of bird flu, including what is being done to prevent its spread. Their websites have the most up-to-date information about bird flu:

• U.S. government. You can find information at www.flu.gov/about_the_flu/h5n1.
• U.S. Centers for Disease Control and Prevention (CDC). You can find information at www.cdc.gov/flu/avianflu.
• World Health Organization (WHO). You can find information at www.who.int/influenza/human_animal_interface/avian_influenza/en.