Hartford Hospital

Search for

Avian Influenza

(Bird Flu, H5N1 Infection)

En Español (Spanish Version)

Definition | Causes | Risk Factors | Symptoms | Diagnosis | Treatment | Prevention

See also:


Avian influenza is a strain of influenza virus that primarily infects birds. It is often called the bird flu.

In Asia and Africa, there have been cases of avian influenza that have the ability to infect humans. The most significant of these avian influenza strains is called H5N1. This strain can cause serious illness and death.

Virus Attacking Cell

Copyright © Nucleus Medical Media, Inc.


Avian influenza is caused by a specific influenza type A virus. The virus is common among wild and domestic birds but rarely infects humans. Occasionally, the virus can mutate which allows it to infect humans.

The virus is passed through contact with an infected animal’s:

  • Saliva or blood
  • Nasal secretions
  • Droppings

Avian influenza is not contracted through eating well-cooked poultry, eggs, or pork products. The virus rarely passes from one human to another, when it does it is usually a weakened version of the virus. Infections are being monitored to see if the virus mutates in a way that allows it to easily pass between humans.

Risk Factors

Close contact with infected poultry increases your chance of avian influenza. This may include domestic or wild ducks, geese, chickens or turkeys.

Your chance of infection is also increased with recent travel to an area known to have avian influenza. Avian influenza outbreaks are most common in Asia, the Middle East, and northeast Africa.


These symptoms may be caused by other less serious conditions. Symptoms of avian influenza may include:

More severe infections can lead to pneumonia or serious organ failure.


Your doctor will ask about your symptoms and medical history. You will be asked about potential exposure opportunities. A physical exam will be done.

Nasal or respiratory secretions or blood can be tested for the presence of the virus.


Antiviral medications can help decrease your symptoms and the length of time you are sick. They can not cure the flu. The sooner the medication is started the more effective it can be. Ideally the medication should be started within 48 hours of the first symptoms.


Some health experts are concerned that this virus could eventually cause a worldwide outbreak known as a pandemic. Medical organizations such as WHO and CDC monitor avian influenza rates worldwide to look for any outbreaks. National and international efforts may be used if there is evidence of a pandemic, to decrease further spread of the infection.

The overall risk of getting avian flu is small. Steps to help you reduce your risk include:

  • Get a yearly flu vaccine. This is the best step to prevent an infection with influenza virus.
  • Avoid traveling to areas where there are avian influenza outbreaks. For the latest travel information, visit the CDC's Traveler's Health page.
  • Avoid contact with potentially infected poultry or swine. This includes farms or open air markets.
  • Wash your hands often if you are in an area where exposure to the influenza virus is possible. Be sure that hands are washed before preparing food. Use a hand sanitizer if clean water is not available for washing.

The Food and Drug Administration (FDA) has a vaccine to protect against H5N1 in adults aged 18-64. It will be made available in the event of an outbreak. Vaccinations can protect the individual and may control the spread of the infection.


Centers for Disease Control


World Health Organization



Canadian Medical Association



Avian influenza. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed/what.php. Updated August 2009. Accessed May 15, 2013.

Avian Influenza A Virus Infections in Humans. Centers for Disease Control and Prevention (CDC) website. Available at: http://www.cdc.gov/flu/avianflu/avian-in-humans.htm. Updated June 21, 2012. Accessed May 15, 2013.

Avian Influenza in Humans. World Health Organization website. Available at: http://www.who.int/influenza/human_animal_interface/avian_influenza/en/. Accessed May 15, 2013.

Cohen J, Powderly WG. Infectious Diseases. 2nd ed. New York, NY: Elsevier; 2004.

Cornelissen LA, de Vries RP, de Boer-Luijtze EA, Rigter A, Rottier PJ, de Haan CA. A single immunization with soluble recombinant trimeric hemagglutinin protects chickens against highly pathogenic avian influenza virus H5N1. PLoS One. 2010;5(5):e10645.

H5N1 Avian Flu. Flu.gov website. Available at: http://www.flu.gov/about_the_flu/h5n1/index.html#. Updated June 21, 2012. Accessed May 15, 2013.

Kilany WH, Arafa A, Erfan AM, et al. Isolation of highly pathogenic avian influenza H5N1 from table eggs after vaccinal break in commercial layer flock. Avian Dis. 2010;54(3):1115-1119.

Weir E, Wong T, Gemmill T. Avian influenza outbreak: update. CMAJ. 2004;170:785-786.

Last reviewed May 2013 by Michael Woods, MD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

CreativeChangePowered by: Creative Change, Inc.