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What There Is to Know About Bird Flu
Your Bird Flu FAQs
WebMD has been in touch with the CDC, the World Health Organization, and infectious disease experts to answer your bird flu questions.
What Is Bird Flu?
Bird flu, or avian influenza, is an infectious disease of birds caused by type A strains of the influenza virus. Bird flu epidemics have occurred worldwide. The recent spread of bird flu has been localized to certain parts of Asia.
Migratory waterfowl - most notably wild ducks - are the natural reservoir of bird flu viruses. It's suspected that infection can spread from wild fowl to domestic poultry, including chickens and turkeys, and then to humans. Live bird markets have also played an important role in the spread of epidemics.
The current bird flu epidemic sweeping through southeast Asia is the largest ever recorded. Because the disease has spread to wild birds - including ducks, which carry the virus without getting sick - it will be hard, if not impossible, to eradicate the virus. Making matters worse, the virus has already learned to infect and kill mammals such as tigers, domestic cats, and pigs.
How Do Humans Get Bird Flu?
People catch bird flu by contact with infected birds or bird droppings. People don't catch the virus from eating fully cooked chicken or eggs. There have been a few cases where one infected person caught the bird flu virus from another person - but only after close personal contact.
Can I Catch Bird Flu From Another Person?
As long as the bird flu virus doesn't mutate into a human flu virus, it won't spread far in people. But sometimes - after close personal contact -- a person who gets bird flu does infect another person. It's not clear exactly how this happens. However, casual contact does not seem to be involved.
Has Bird Flu Been Seen in the U.S.?
Bird flu pops up in the U.S. from time to time. The last time a highly dangerous strain appeared was a February 2004 outbreak near Houston, Texas. This involved a different virus strain than the one circulating in Asia. By April 2004, the outbreak had been eradicated. No human infections were detected.
What Are the Symptoms of Bird Flu in Humans?
It changes every year. Humans who have caught this year's bird flu from chickens start out with normal flu-like symptoms. This worsens to become a severe respiratory disease that has been fatal in a high percentage of cases.
In February 2005, researchers in Vietnam reported human cases of bird flu in which the virus infected the brain and digestive tract of two children. Both died. These cases make it clear that bird flu in humans may not always look like typical cases of flu.
No human cases of bird flu have been seen in the U.S. or North America. But as a precaution, the CDC is asking people who have traveled to East Asia to see a doctor if they develop flu-like symptoms. If so, it's important to tell the doctor about having visited these areas so the proper tests can be done.
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