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Diseases » Flu » Introduction


Flu: Introduction

The flu, medically known as influenza, is a common infection of the respiratory tract, including the nose, throat, bronchial tubes and lungs. The flu is caused by a virus and is very contagious. The effects of the flu can vary from mild to severe to life-threatening, depending on the type of flu and individual factors, such as age, general health status, and coexisting conditions, such as renal failure.

Every year 5 percent to 20 percent of the population gets the flu, and about 36,000 people die from flu-related complications, according to the National Institutes of Health. The flu generally occurs in winter months in small outbreaks. In some years, such as in 2009, many more people become infected and die of the flu due to the development and spread of certain flu viruses. In 2009, this virus was the novel H1N1 virus, which causes the novel H1N1 flu.

The flu virus spreads from person to person when someone with the flu talks, coughs or sneezes. This shoots droplets contaminated with the flu virus into the air where they can be breathed in by others. The flu also spreads by touching an infected person or a surface contaminated by the virus, such as a contaminated drinking glass or doorknob.

There are three main types of viruses that can cause the flu: influenza type A virus, influenza type B virus, and influenza type C virus. Flu caused by influenza type C virus, is generally mild with symptoms similar to a cold and does not cause outbreaks in populations. Strains of Influenza type A virus are often at the root of global pandemics of flu, and strains of influenza type B virus can lead to outbreaks in smaller geographic locales.

Symptoms of the flu include can vary greatly among individuals. They may include fever, sneezing, body aches, headache, fatigue, sore throat, and cough. For more information on symptoms, refer to symptoms of flu.

Complications of the flu can be serious, even life-threatening and include pneumonia, acute bronchitis, encephalitis, and death. People at risk for getting the flu and developing its serious complications include infants and young children, residents of long-term care facilities, pregnant women, and health care workers. Other people at risk include those who are over the age of 50, are care takers for young children, or who have an immunodeficiency disorder, a suppressed immune system, or a chronic disorder, such as diabetes or cardiovascular disease.

The flu can generally be diagnosed by taking a thorough health history, including symptoms, and performing a physical examination. Although testing is available to help detect the flu, it is not always accurate and cannot distinguish between various types of flu. Because the symptoms of the flu can mimic other diseases, such as strep throat, some other forms of testing, such as a throat culture and sensitivity, may be done to rule out other diseases. For information on misdiagnosis, refer to misdiagnosis of flu.

The best protection from getting or spreading the flu includes covering your mouth and nose with your elbow or a tissue when you sneeze or cough and washing hands frequently with soap and water for at least 15 seconds. You can also use antibacterial cleaners to clean hands and surfaces. It is also important to avoid touching your eyes, nose, and mouth, which can transmit the virus from your hands into your body. Getting a yearly flu shot is also key, especially for those at risk for contracting the flu or its serious complications.

There is currently no cure for the flu. Treatment includes measures to help relieve symptoms and keep the body as strong as possible to minimize the risk of developing complications. This includes rest, medications to ease body aches and fever, and drinking plenty of fluids. The age-old remedy of chicken soup may actually help to break up congestion and provides easy-to-digest nutrients to help keep up strength.

Antibiotics are ineffective against the flu, but for some people, a prescribed antiviral drug may be appropriate to help shorten the length of the disease. For more information on treatment, refer to treatment of flu. ...more »

Flu: Flu is a common respiratory virus that is usually more severe than the common cold. Symptoms often include high fever, headache, fatigue, weakness, and exhaustion. Cold-like symptoms such as sore throat, runny nose, and stuffiness can also occur but are less common than in common cold.

Early diagnosis of flu often involves distinguishing flu from common cold, which is not always easy, but is important because of newer antiviral medications for the flu. There are numerous other less common conditions that start out like the flu (see flu-like symptoms). ...more »

Flu: Animations

Flu: Broader Related Topics


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