Questions and Answers on Avian (Bird) Flu

What is avian influenza (bird flu)?

Bird flu is an infection caused by avian (bird) influenza (flu) viruses. These flu viruses occur naturally among birds. Wild birds worldwide carry the viruses in their intestines, but usually do not get sick from them. However, bird flu is very contagious among birds and can make some domesticated birds; including chickens, ducks, and turkeys, very sick or die.

Avian influenza is caused by the influenza A virus. Migratory waterfowl, most notably wild ducks, are the natural reservoir for all influenza A viruses. It was first identified in Italy more than 100 years ago.

Do bird flu viruses infect humans?

Bird flu viruses do not usually infect humans, but several cases of human infection with bird flu viruses have occurred since 1997. Infected birds shed flu virus in their saliva, nasal secretions, and feces. Susceptible birds become infected when they have contact with contaminated excretions or surfaces that are contaminated with excretions. It is believed that most cases of bird flu infection in humans have resulted from contact with infected poultry or contaminated surfaces. The spread of avian influenza viruses from one ill person to another has been reported very rarely, and transmission has not been observed to continue beyond one person. This is a very important point.

The concern is that influenza A viruses are constantly changing, and they might adapt over time to infect and spread among humans.

Is there a vaccine to protect humans from avian flu (the H5N1 virus)?

No. However, vaccine development efforts are taking place. Research studies to test a vaccine to protect humans against H5N1 virus began in April 2005, and a series of clinical trials is underway. For more information, visit the NIH website at http://www3.niaid.nih.gov/news/newsreleases/2005/avianfluax.htm

Will a regular flu shot protect me again avian flu?

No. But a flu shot will help protect you against the other (much more common) types of flu. Making sure that you don't get the flu will help insure that you are stronger if Avian influenza does spread.

What are the symptoms of bird flu in humans?

Symptoms of bird flu in humans have ranged from typical flu-like symptoms (fever, cough, sore throat and muscle aches) to eye infections, pneumonia, severe respiratory diseases (such as acute respiratory distress), and other severe and life-threatening complications. The symptoms of bird flu may depend on which virus caused the infection.

How is bird flu in humans treated?

Studies done in laboratories suggest that the prescription medicines approved for human flu viruses (particularly Tamiflu) should work in preventing bird flu infection in humans. However, flu viruses can become resistant to these drugs, so these medications may not always work. Unfortunately, some resistance has been observed already.

What are the risks to humans from bird flu?

The risks from bird flu are generally low to most people because the viruses occur mainly among birds and do not usually infect humans. However, during an outbreak of bird flu among poultry (chicken, ducks and turkeys), there is a possible risk to people who have contact with infected birds or surfaces that have been contaminated with excretions from infected birds. The current outbreak of avian influenza A (H5N1) among poultry in Asia and Europe is an example of a bird flu outbreak that has caused human infections and deaths.

In rare instances, limited human-to-human spread of H5N1 virus has occurred, and transmission has not been observed to continue beyond one person.

For more information about avian influenza and food safety issues, visit the http://www.who.int/foodsafety/micro/avian/en/.

There has been a lot of media coverage about avian flu in Asia and Europe. Should that concern us?

Outbreaks of avian flu and specifically influenza H5N1 occurred among poultry in eight countries in Asia (Cambodia, China, Indonesia, Japan, Laos, South Korea, Thailand, and Vietnam) during late 2003 and early 2004. At that time, more than 100 million birds in the affected countries either died from the disease or were killed in order to try to control the outbreak. By March 2004, the outbreak was reported to be under control. Beginning in late June 2004, however, new outbreaks of influenza H5N1 among poultry were reported by several countries in Asia. It is believed that these outbreaks are ongoing. Most recently, influenza H5N1 has been reported among poultry in Turkey and Romania. Human infections of influenza A (H5N1) have been reported in Cambodia, Indonesia, Thailand, and Vietnam.

What is the risk to humans from the H5N1 avian flu virus in Asia and Europe?

The H5N1 virus does not usually infect humans. In 1997, however, the first case of spread from a bird to a human was seen during an outbreak of bird flu in poultry in Hong Kong. The virus caused severe respiratory illness in 18 people, 6 of whom died. Since that time, there have been other cases of H5N1 infection among humans. Most of these cases have occurred from contact with infected poultry or contaminated surfaces; however, it is thought that a few cases of human-to-human spread of H5N1 have occurred.

So far, spread of H5N1 virus from person to person has been rare. However, because all influenza viruses have the ability to change, scientists are concerned that the H5N1 virus one day could be able to infect humans and spread easily from one person to another. Because these viruses do not commonly infect humans, there is little or no immune protection against them in the human population.

If the H5N1 virus were able to infect people and spread easily from person to person, an influenza pandemic (worldwide outbreak of disease) could begin. However, experts from around the world are watching the H5N1 situation very closely and are preparing for the possibility that the virus may begin to spread more easily.

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