Influenza is an acute respiratory disease, which is caused by the influenza virus. In case of influenza, a person feels very sick. Influenza is a contagious disease that spreads rapidly. One can get influenza every year. For most people, influenza is a nasty disease that passes on its own. In people with poor immune system, influenza can be very serious and fatal.


The main types of influenza are caused by the influenza virus type A, B and C. This virus is found in the airway and causes an infection there, which has also consequences for the rest of the body. The virus is present in nasal discharge, mucus and saliva. The virus passes easily through the air or via hands from one to the other. For example by coughing, sneezing, talking or shaking hands.
A person can get infected by inhaling the virus or when the virus enters the nose or mouth via the hands. The virus spreads in the entire body. After infection, it may take one to three days before symptoms occur.


Influenza often arises suddenly. Within hours, a person may feel very ill. The patient is in bed for a few days and sometimes feels tired and miserable for a long time. Influenza looks like a bad cold with fever, chills, sore throat and sometimes a dry cough. Other symptoms are poor appetite, breathlessness and fatigue without being able to sleep well. Headache, stiff and aching limbs and muscle pain are also symptoms of influenza.
The cough can be persistent and the patient can feel weak and listless for one to three weeks, while the other symptoms usually disappear after two to seven days.


The diagnosis can be based on the symptoms. Additional examination is usually not necessary. By doing special blood tests or a culture from a nasal or throat sample using a cotton swab, the diagnosis can be confirmed.


If there are no complications, the influenza doesn’t need to be treated. Influenza usually disappears spontaneously. Running the disease out is the best remedy. Antibiotics don’t help in an ordinary influenza. Antibiotics help against bacteria and influenza is caused by a virus. The symptoms of influenza, such as fever and cough, can be treated with medication. In very fragile patients, so-called viral inhibitors are sometimes prescribed. These viral inhibitors can shorten the period of illness by one to one and a half day and reduce the risk of complications.
There are vaccinations that protect for seventy to ninety percent against the influenza virus type A or B during six months. Influenza viruses, however, are difficult to combat because they are constantly changing. Therefore, an old vaccine can't stop a new virus.


Although influenza is usually harmless and passes on its own, it may lead to complications. Examples of complications are: sore throat, infections of the airway (bronchitis) and lungs (pneumonia), infection of the heart (myocarditis), meningitis, ear infections and (secondary) infections by bacteria. These complications can progress severely and people can die. During an influenza epidemic, a lethal pneumonia may occur, even in previously healthy people.