Q: Are there differences between influenza (the flu) and avian influenza (bird flu)?
A: Yes. Influenza, or the flu, is a contagious illness caused by influenza viruses that attack the respiratory tract--the nose, throat, and lungs. Animals, including birds, as well as humans, can be affected by flu viruses. The flu can cause mild to severe illness and even death. Older people, young children, and people with certain health conditions are most likely to suffer serious complications.
Flu symptoms include fever (usually high), headache, extreme tiredness, dry cough, sore throat, runny or stuffy nose, and muscle aches. Stomach symptoms, such as nausea, vomiting, and diarrhea, also can occur, but they are more common in children than adults. In the most severe, patients can develop life-threatening pneumonia.
In an average year in the United States:
5 to 20 percent of the population gets the flu
More than 200,000 people are hospitalized from flu complications
Flu-associated deaths in the U.S. ranged from a low of about 3,000 to a high of about 49,000 people between 1976 and 2006.
The best way for you to protect yourself is to get a flu vaccination each fall.
Avian influenza, or bird flu, is an infection caused by avian flu viruses. These viruses occur naturally among birds. Worldwide, wild birds carry the viruses in their intestines, but they usually do not get sick from them. Avian flu, however, which is spread through saliva, nasal secretions, and feces, is very contagious among birds. It can make some domesticated birds--including chickens, ducks, and turkeys--very sick and kill them.
Effect on birds
Q: How and where has avian flu affected birds?
A: Some avian flu causes only mild symptoms, but the most severe form may spread rapidly through poultry flocks and can kill all or almost all of a flock, often within 48 hours. Influenza A (H5N1), the subtype of most concern now, was first discovered among birds in China in 1986. It wasn't until late 2003, however, that it began spreading quickly through bird populations there and in seven other Asian countries. By March 2004, after more than 100 million birds had either died from the disease or been killed to control the outbreaks, the disease spread was considered under control.
But since 2004, new outbreaks in poultry and other birds have been reported in Asia, Europe, the Near East, and Africa. The Centers for Disease Control and Prevention (CDC) expects the outbreaks may continue, with occasional cases of viral illness spreading people in those areas.
Q: Do avian influenza viruses infect humans?
A: Bird flu viruses usually do not infect humans, but more than 300 confirmed cases of human infection with bird flu viruses have occurred since 1997. The World Health Organization (WHO) maintains situation updates and cumulative reports of human cases of avian influenza A (H5N1). This virus subtype was first detected in humans in Hong Kong in 1997. Six of the known 18 people infected died. Since then, human cases of influenza A (H5N1) infection have been reported in Azerbaijan, Cambodia, China, Djibouti, Egypt, Indonesia, Iraq, Lao People's Democratic Republic, Nigeria, Thailand, Turkey, and Vietnam.
Q: How do people become infected with avian influenza viruses?
A: Most cases of avian influenza infection in humans have resulted from direct or close contact with infected poultry or surfaces contaminated with secretions and excretions from infected birds. In very rare cases, avian flu viruses have spread from one ill person to another person, and transmission has not continued beyond that second person.
Q: What precautions can I take to protect myself and my family?
A: To limit the spread of germs and prevent infection, the CDC offers these recommendations:
Wash hands frequently with soap and water.
Cover coughs and sneezes with tissues.
Stay away from others as much as possible if they are sick.
Stay home from work and school if you are sick.
Don't shake hands with anyone who appears to be sick.