The influenza is a contagious respiratory illness caused by influenza viruses. While most healthy people recover from the influenza without complications, some people, such as older people, young children, and people with certain health conditions, are at high risk for serious complications from influenza.The influenza-associated primary respiratory hospitalization rates of children younger than 5 years were similar to that of persons aged 50 through 64 years (108 per 100,000 persons).

Influenza usually starts suddenly and may include fever (usually high), headache, tiredness (can be extreme), dry cough, sore throat, runny or stuffy nose and muscular aches and pains, especially in your back, arms and legs. Children can also feel nauseous and experience vomiting and diarrhoea.
A lot of different illnesses, including the common cold, can have similar symptoms. While you may cough and sneeze with the influenza, you're also likely to have a high fever, chills and body aches — signs and symptoms you won't typically have with a cold. Real influenza usually doesn't affect your intestines.
Adults may be able to infect others with influenza 1 day before getting symptoms and 3 – 7 days after getting sick. So it is possible to give someone influenza before you know you’re sick as well as while you are sick. Children may be contagious for longer than a week. Persons with an immune compromising illness can shed virus for weeks or months.

Influenza like illness (ILI) interferes with work and leisure time activities. Workers stay at home during 2.8 days and in bed during 2.4 days and 73 % experience interference with activities at home and 84% with leisure activities.

1. Prevention of influenza

By far, the single best way to prevent the influenza is for individuals to get a vaccination each fall. Practicing healthy habits will help you stay healthy during the influenza season and all year long. Get plenty of sleep, be physically active, manage your stress, drink plenty of fluids, and eat nutritious food. Avoid close contact with people who have influenza and wash your hands often.
The human influenza viruses generally can survive on surfaces for between 2 and 8 hours. The influenza virus is destroyed by heat (75-100°C). In addition, several chemical germicides, including chlorine, hydrogen peroxide, detergents (soap), iodine-based antiseptics, and alcohols are effective against influenza viruses.

2. Do’s and don’ts if you get sick

Here are things you can do to speed recovery: Get plenty of sleep. Sleep gives your body time to rebuild strength to fight off the virus. Eat a balanced diet. A healthy diet provides the vitamins and nutrients to build and maintain a healthy immune system. Stay hydrated. Water helps reduce the risk of dehydration from fever and diarrhea. Avoid using alcohol and tobacco. Take medication to relieve the symptoms of influenza (but never give aspirin to children or teenagers who have influenza-like symptoms – and particularly fever – without first speaking to your doctor.)

2a. Help prevent the spread of influenza:

• Cover your nose and mouth with a tissue when you cough or sneeze and throw the tissue away after you use it.
• Wash your hands often with soap and water, especially after you cough or sneeze. If you are not near water, use an alcohol-based hand cleaner.
• Keep your distance from others to protect them from getting sick too.
• Stay home from work, school, and errands if you have influenza. You will help prevent others from catching your illness.
• Try not to touch your eyes, nose, or mouth. Germs often spread this way.

2b. Advice for caregivers of children less than 6 months old who get the flu

• Check with your health-care provider. (If you have influenza, your doctor may prescribe antiviral medications for you.)
• Try to minimize contact with your infant as much as possible.
• Cover your nose and mouth with a tissue when sneezing or coughing, and put your used tissue in a waste basket.
•  Wash your hands or use an alcohol-based hand rub frequently and as soon as possible if you have sneezed or coughed on your hands.
• Before engaging in any activity within 3 feet of your infant (including feeding, changing, rocking, reading to your child), put on a surgical mask (available in most drugstores) and thoroughly wash and dry your hands. Do not remove your surgical mask until you are done and you have put your infant down.
• Take these precautions for the first 7 days of your illness (beginning the first day you notice symptoms).
• Be Watchful: Observe your infant closely for symptoms of respiratory illness. If your child develops a fever, respiratory symptoms, or is less responsive than normal, contact your child’s doctor. If severe difficulty in breathing occurs, immediate medical attention is needed.

2c. Physical exercise routines and sports

Don't exercise when you have a fever. A fever indicates you're battling a virus and exercising in this state increases the risk of dehydration, heatstroke and heart failure.
In case of influenza or cold modify the intensity of exercise routines. Don't try to sweat your way through the ailment with intense exercise. You might make your illness worse. Moderate exercise is fine for a cold, as long as your heart rate and body temperature do not increase excessively. A good rule of thumb is to exercise for 2 days at a lower than normal intensity for each day you were sick. If you have below-the- neck signs as tiredness, muscle aches, vomiting, diarrhea, chills, swollen lymph glands or hacking cough, take at least two weeks off before returning to intense activity. Give your body time to recover.

3. Preventing spread of the influenza in child care settings

Influenza vaccination is encouraged for children and care providers. Children and care providers should wash their hands or use alcohol-based hand rubs and the child care environment should be kept clean. Children and care providers should cover their noses and mouths when sneezing or coughing and all children should be observed for symptoms of respiratory illness, especially when there is increased influenza in the community. Parents should keep their sick children home until they have been without fever for 24 hours. Also sick care providers should stay home.

4. Sports

Athletes who participate in winter sports are vulnerable to influenza because they are in close physical contact and share locker rooms and, often, water bottles.
There is a link between regular exercise and improved immunity response. During moderate exercise, immune cells circulate more quickly through your body and are better at destroying viruses and bacteria. However, over training can suppress your immune functions and increase your susceptibility to upper respiratory tract and other infections. Also, trying new and harder activities can lead to failure, causing physiological and psychological stress that can have an adverse effect on the immune system.
Especially in elite athletes even a mild viral infection can be devastating due to loss of important training hours and/or compromise of competitive performance. Due to their intensive training program they can be regarded, as a population at risk of various infections, and a yearly immunization against influenza is recommended.