Bird flu, or avian flu, is an influenza virus strain that typically infects birds - including wild birds like ducks and domestic birds like chickens.

There are many forms of bird flu, and most are relatively harmless, producing mild symptoms or even no symptoms. However, several strains of bird flu produce a highly contagious disease that kills quickly and could lead to a massive bird flu epidemic. These dangerous viruses are known as "highly pathogenic avian influenza."

One such bird flu virus is currently spreading among chickens in Asian countries. In recent years it was discovered that the bird flu virus can infect people who have close contact with live birds.

The current strain cannot be passed from human to human, but heath officials say it may mutate and become contagious in our species. If that happens, according to David Nabarro of the U.N. and World Health Organization, "an epidemic could kill between 5 and 150 million people," which would be a much larger disaster than 2004's Asian Tsunami and 2005's U.S. hurricanes combined.

Symptoms of bird flu (avian flu) in humans include:

Conjunctivitis
Cough
Fever
Muscle aches
Sore throat
(Severe cases) Breathing problem and pneumonia

How dangerous is bird flu?

Bird flu can be fatal.

There have been a number of small outbreaks of bird flu since 1997, and people who get it appear to have a high mortality rate.

*1997 Hong Kong - 18 people were infected and 6 people died.

*There were two cases and one death in Hong Kong in 2003.

*As many as 10 deaths have been linked to an outbreak in a number of Asian countries last year.

How can bird flu be treated?

Anyone with bird flu symptoms should see a health care professional immediately. The bird flu virus currently infecting birds in Asia that has caused human illness and death appears to be resistant to Tamiflu, according to officials at Queen Mary Hospital in Australia. Tamiflu is the most common drug used to treat flu in humans.

There currently is no vaccine to protect humans against the strain of bird flu virus that's been detected in Asia. However, research studies to test a bird flu vaccine to protect humans began in April 2005.

Additional information and resources, including tips for avoiding bird flu, can be found at http://www.symptoms.name/birdflusymptoms.htm