10 Facts About Influenza

Influenza, the scientific name for the flu, is a highly contagious respiratory infection. Influenza is a viral infection of the throat, nose, lungs and bronchial tubes. According to the Centers for Disease Control and Prevention (CDC), 5 to 20 percent of Americans catch influenza annually and more than 200,000 hospitalizations occur from flu complications every year.

History

• According to the National Geographic, influenza was a global catastrophe in 1918, striking a fifth of the Earth's population and taking more than 50 million lives. About every 30 to 40 years the flu virus typically alters just enough that people's normal immune systems are caught off guard and a new, intensive influenza virus manifests. The most recent case of this is the H1N1 flu of 2009.

Types of Influenza

• In the 1930s, scientists identified the influenza virus. Since then, scientists have classified influenza into three categories: Type A, B and C. Influenza Type A and B are responsible for the yearly flu epidemic. Humans and animals can contract Influenza Type A, but only humans can contract the Influenza B virus. In addition, Influenza B reactions are not as severe as the reactions in the Influenza A. Influenza C reaction is milder than both Influenza A and B.

Transmission

• The influenza virus is contagious and can spread quickly through the air when an infected person coughs or sneezes. The body then contracts the flu virus through mucus membranes in the nose, mouth or eyes. The CDC reports adults may be able to infect others beginning one day before symptoms develop and up to five days after becoming sick.

Symptoms

• Some people do not realize they have the flu. Characteristics of the flu are a sudden arrival of a high fever, headache, dry cough, sore throat, muscle aches, chills, sweats, loss of appetite, joint pain, runny nose and excessive fatigue. In addition, some children may experience vomiting and diarrhea.

High Risk Patients

• The CDC reports the elderly represent more than 90 percent of fatalities attributed to influenza and pneumonia. Other groups at high risk for serious influenza problems are the elderly, younger children, people with weak immune systems and people with chronic underlying sicknesses, such as asthma, heart disease or diabetes.

Vaccine Types

• There are two types of the influenza vaccine. The "flu shot" is an inactivated vaccine made from a killed virus injected into the arm. Vaccines can also be given in the form of a nasal spray. People older than 6 months can receive a flu shot. Patients between the ages of 2 and 49, who are not pregnant, may receive the nasal spray. People need to receive a flu vaccination yearly because the influenza virus changes constantly and creates a new strain.

Vaccination Recipients

• The CDC recommends that anyone who wants to lessen the chance of contracting seasonal influenza should get the vaccine. However, there are some patients the CDC recommends should receive the vaccination regardless. High risk patients, who are likely to have severe complications from the flu, or who live with or watch after a high risk patient should get the vaccine. There are even some patients who should not receive a flu vaccination without consulting a doctor. People who have severe allergic reactions to chicken eggs should not get the vaccine. Anyone who has suffered a severe reaction to a previous flu shot, children younger than 6 months and patients who develop Guillain-Barre Syndrome (GBS) within 6 months of a previous flu vaccine should also not receive the vaccine.

Complications

• Pneumonia, severe cardiopulmonary conditions and other chronic diseases can contribute to influenza-related deaths. Other less life-threatening complications may also occur if influenza is left untreated. These include ear infections, dehydration, sinusitis and bronchitis.

Seasonal Epidemics

• According to the World Health Organization, flu epidemics normally happen in autumn and winter. However, in the tropics the influenza virus spreads throughout the year. This epidemic results in approximately 3 million to 5 million serious annual cases worldwide and 250,000 to 500,000 fatalities.

Misconception

• Many people often confuse gastroenteritis, also known as the "stomach flu," with influenza. Gastroenteritis symptoms like diarrhea and vomiting do not occur because of the flu virus. Influenza infections are mainly respiratory conditions, not an intestinal or stomach condition.