Flu is an infectious disease that anyone can get sick with. Influenza is caused by a virus that enters the nasopharynx of others from infected people.
Usually the flu starts suddenly. Influenza pathogens, type A and B viruses, are aggressive and extremely fast, so within hours of infection, the virus causes deep damage to the respiratory tract, opening the way for bacteria to enter.
Influenza symptoms include fever, fever of 37.5-39°C, headache, muscle and joint pain, chills, fatigue, cough, runny nose or stuffed nose, sore throat and sore throat.
Flu can be confused with other diseases, so a clear diagnosis should be made by a doctor, who also prescribes treatment tactics.
Learn more about the rules for influenza prevention