Introduction & Symptoms

Influenza -- commonly shortened to "flu" -- is an extremely contagious viral disease that appears most frequently in winter and early spring. The infection spreads through the upper respiratory tract and sometimes goes into the lungs. The virus typically sweeps through large groups of people who share indoor space, such as schools, offices and nursing homes. The global influenza epidemic of 1918 -- which started in a military training camp in Kansas -- eventually killed some 500,000 people throughout the United States.

Symptoms

If you start to develop cold symptoms but starting more rapidly and rather more violently, with higher fever and severe aches and pains, often in the back and muscles, then you may well be developing influenza. This may be associated with severe headache, cough, and, as a result of the fever, intermittent sweating and shivering. Sometimes there is a gastrointestinal element, with vomiting and/or diarrhoea.

Many people think they have had "flu" when all that they have suffered is a bad cold. When you have influenza you will know the difference. Most people will find it impossible to leave their bed and feel terrible.

The worst symptoms usually last for three to five days, and then should begin to improve. It is common to need two to three weeks off work as there is considerable debility left after the feverish illness is over. Do not be surprised to be quite depressed, this is a natural after-effect of the condition.

Influenza makes everyone feel terrible, but most people recover. It does, however have a small, but significant mortality, especially in the very young, the very old, and those with poor immunity.

Causes

The flu virus is transmitted by inhaling droplets in the air that contain the virus, or by handling items contaminated by an infected person. The symptoms start to develop from one to four days after infection with the virus.

Researchers divide influenza viruses into three general categories: types A, B and C. While all three types can mutate, or change into new strains, type A influenza mutates constantly, yielding new strains of the virus every few years. This means that you can never develop a permanent immunity to influenza. Even if you develop antibodies against a flu virus one year, those antibodies are unlikely to protect you against a new strain of the virus the next year. Type A mutations are responsible for major epidemics every several years. Types B and C are less common and result in local outbreaks and milder cases. Type B has also been linked to the development of Reye's syndrome, a potentially fatal complication of influenza and other viral infections (such as chickenpox) that usually affects children. The risk of Reye's syndrome increases in children who take aspirin during a viral illness.

Most influenza viruses that infect humans seem to originate in parts of Asia where close contact between livestock and people creates a hospitable environment for the mutation and transmission of viruses. Swine, or pigs, can catch both avian (meaning from birds or poultry) and human forms of a virus, and act as hosts for these different viral strains to meet and mutate into new forms. The swine then infect people with the new form of the virus in the same way in which people infect each other -- by transmitting viruses through exchange of droplets in the air.

Diagnostic and Test Procedures

All three types of influenza mimic the basic symptoms of the common cold, such as cough and headache. Your doctor may take a throat culture or blood test to rule out the possibility of other ailments such as strep throat or, if public-health officials are gathering statistics on an influenza outbreak, to identify the specific viral strain.

Treatment

Influenza will run its course regardless of how you treat it. Because it is a viral disease, it does not respond to antibiotics. If you are in good health, influenza will probably pass with no complications after a week or so of bed rest and self-care at home. If you are over 65, are a diabetic or have another chronic disease, talk to your physician about being immunized before winter sets in. If you then come down with flu anyway, make sure your doctor monitors your progress so that any complications can be caught and treated appropriately.

Recently Approved Medications

Two new drugs have recently been aprroved to decrease the duration and severity of influenza smptoms. These  medications: known as Tamiflu and Relenza are FDA approved prescription medications

Conventional Medicine

Doctors have no single treatment that applies to all cases of influenza. You will probably be told to rest in bed, eat nourishing food and drink lots of liquids. Fluids are especially important to help avoid dehydration from fever and for loosening up respiratory tract secretions.

You can try over-the-counter medicines to ease the discomfort of your cough, nasal congestion and sore throat. A steam vaporizer in your room puts moisture into the air and may make breathing easier. If you are feverish and have muscle aches, analgesics like aspirin, ibuprofen or acetaminophen may help you feel better.