Home > Health Library > Avian Influenza (Bird Flu)
Bird flu is an infection caused by a certain kind of
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.
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.
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
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. 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 also worry because the
bird flu virus is so different from other flu viruses that our bodies do
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 he or she gets bird flu.
At first, the symptoms of
bird flu can be the same as common flu symptoms, such
Sometimes bird flu also can cause other symptoms, such as:
Bird flu can quickly
acute respiratory distress syndrome, a serious lung
problem that can be deadly. For the people who die from bird flu, the average
length of time from the start of symptoms until death is 9 to 10 days.footnote 1
Call your doctor right away if you have traveled
somewhere or live in an area where there is bird flu and you have a fever and a
hard time breathing.
If your doctor thinks that you may have bird flu,
he or she 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
Some questions your doctor might ask are:
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
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). More
than half of the time, bird flu leads to death.
The World Health Organization and the
U.S. Centers for Disease Control and Prevention are preparing for the
possibility that bird flu could spread to people all over the world in what is
called a pandemic. The U.S. Food and Drug Administration (FDA)
has approved human vaccines to protect against bird flu. But immunization is not
available for the public right now. The vaccines are kept in a U.S.
government stockpile.footnote 2 Officials are also storing up
large supplies of antiviral medicines. The U.S. government has also developed a
flu plan. This is a plan to prepare for a pandemic and to make sure that as few
people as possible get the virus.
organizations now require that all infected birds be killed. Some countries
have programs to clean up poultry farms and to check that all birds are healthy
before they are sold. In 2004, the United States stopped buying poultry from
most Asian countries.
Even though there is a lot of
talk about bird flu, most people in the United States don't have to worry about
getting it. As of April 2012, no cases of bird flu in humans had been found
in the U.S. But you can take steps to lower your chances of getting
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:
Writing Committee of the Second World Health
Organization Consultation on Clinical Aspects of Human Infection with Avian
Influenza A (H5N1) Virus (2008). Update on avian influenza A (H5N1) virus
infection in humans. New England Journal of Medicine,
U.S. Food and Drug Administration (2007). FDA approves
first U.S. vaccine for humans against the avian influenza virus H5N1.
FDA News. Available online:
Other Works Consulted
Writing Committee of the World Health Organization
(WHO) Consultation on Human Influenza (2005). Avian influenza A (H5N1)
infection in humans. New England Journal of Medicine,
Public Health Agency of Canada (2012). Current avian influenza (H5N1) affected areas. Available online: http://www.phac-aspc.gc.ca/h5n1/index-eng.php.
Schünemann HJ, et al. (2007). WHO rapid advice
guidelines for pharmacological management of sporadic human infection with
avian influenza A (H5N1) virus. Lancet Infectious Disease, 7(1): 21–31.
U.K. Department of Health (2011). Bird flu and pandemic influenza: What are the risks? Available online: http://www.dh.gov.uk/en/Aboutus/MinistersandDepartmentLeaders/ChiefMedicalOfficer/CMOtopics/DH_4102997.
Ungchusak K, et al. (2005). Probable person-to-person
transmission of avian influenza A (H5N1). New England Journal of Medicine, 352(4): 333–340.
World Health Organization (2011). Fact Sheet: Avian Influenza ("Bird Flu"). Available online:
ByHealthwise StaffPrimary Medical ReviewerAdam Husney, MD - Family MedicineSpecialist Medical ReviewerW. David Colby IV, MSc, MD, FRCPC - Infectious Disease
Current as ofNovember 14, 2014
Current as of:
November 14, 2014
Adam Husney, MD - Family Medicine & W. David Colby IV, MSc, MD, FRCPC - Infectious Disease
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