But, healthy patients can still take important steps to reduce their chances of getting the flu. In addition to preventive measures such as frequent hand washing, covering coughs, and avoiding close contact with sick people, learning about the flu can help patients protect themselves from getting sick. The fourth edition of the American Medical Association Family Medical Guide (Wiley; 2004; ISBN: 0-471-26911-5; Cloth/$45.00) is an excellent source of information about influenza-what it is, its symptoms, and how it is diagnosed and treated. Below are some facts and advice you'll find in this indispensable reference book:

What Is Influenza?

Influenza, usually called the flu, is a viral infection of the respiratory tract. The flu can spread from the nose or mouth to the rest of the respiratory system, including the lungs. It is usually spread by touching an infected person or contaminated surface or by inhaling infected droplets coughed or sneezed into the air. If a bacterial infection develops in addition to the viral infection and travels from the upper respiratory tract to the lungs, it can cause more serious disorders, such as acute bronchitis or pneumonia. Influenza kills about 36,000 people a year in the United States.

There are three main types of influenza virus: A, B, and C. If you have had the flu caused by a type C virus (a relatively mild type of flu with symptoms similar to those of a cold), you are immune to it for life. If you have been infected with a particular strain of a type A or B influenza virus, you have immunity to that strain only. Although both A and B influenza viruses can produce new strains that can overcome a person's immunity, the type B virus seldom alters itself sufficiently to do so. But the type A virus constantly changes, and the changes are significant enough to make it look like a new virus to the immune system. For this reason, type A viruses cause most flu epidemics and severe outbreaks. These strains are usually named after their place of origin (such as the Hong Kong flu).

Influenza usually occurs in small outbreaks, often in the winter. Every few years, in unpredictable intervals, it occurs in epidemics. Two or three epidemics caused by different strains of the virus can occur at the same time. Epidemics die out when everyone who has been infected by a particular strain of a flu virus becomes immune to that strain.

What Are the Symptoms?

Symptoms of the flu vary widely. You may have a fever with shaking chills, sneezing, headache, muscle aches, and sore throat. You may then develop a dry, hacking cough and chest pain. You will probably feel very weak. Some children have abdominal pain and seizures. If you have no complications, you should recover in one to two weeks, although you may still feel weak for a few weeks. If you seem to be the only person who has the flu, you may have some other viral illness such as mononucleosis.

See your doctor if your symptoms are severe, last longer than ten days, or seem to have spread to your lungs (causing wheezing, shortness of breath, or a painful cough), or if you have a chronic disease (especially a lung disorder or an immune system disorder). You should also see your doctor if your fever lasts longer than three or four days.

Diagnosing and Treating the Flu

Doctors can usually diagnose the flu by the symptoms, especially when they occur during flu season in fall or winter. If you have symptoms that persist, your doctor will examine you to see if they could be caused by another disease.

There is no cure for influenza, but you can take measures to relieve the symptoms. Rest, stay comfortably warm (but not hot), and drink plenty of water to help prevent dehydration. Take an over-the-counter pain reliever such as acetaminophen or ibuprofen to ease aches and pains and help you sleep. Check with your doctor before you use a cough suppressant or any other medication advertised to relieve flu symptoms.

For infants and very young children who cannot blow their nose, use a bulb syringe (available at most pharmacies) to suck the mucus out of their nose. This will help them breathe more easily and keep mucus from dripping down their throat, which can cause coughing and stomachaches (from swallowed mucus).

Two Words of Warning

Antibiotics are not effective against the viruses that cause influenza. Your doctor will prescribe an antibiotic only if your influenza has been complicated by a bacterial infection. If you are older or in poor health, your doctor may prescribe amantadine, oseltamivir, or zanamivir if you have been exposed to the flu virus or if you have flu symptoms. These antiviral drugs can prevent or relieve symptoms caused by an influenza A virus.

Do not give aspirin to children or adolescents. It is dangerous to give aspirin to children or adolescents who have a fever. Use of aspirin in children has been linked with Reye's syndrome, a rare but potentially fatal childhood disorder.

© 2005 HealthNewsDigest.com