Depending on the age and general resistance more or less from one to four days after infection the victim starts experiencing first flu symptoms. The symptoms are oftentimes very sudden and harsh. The influenza symptoms include:
  • sudden and severe headache
  • extreme coldness
  • chills, dry cough,
  • fatigue
  • irritated watering eyes
  • abdominal pain (in children with influenza virus type B)
  • fever often running as high as 40 degrees celsius (104 degrees fahrenheit)

Subsequently, there may be even more symptoms such as nasal congestion and sore throat. Flu victims also feel weak and tired for several days.

Complications caused by influenza arise from bacterial infections of the lower respiratory tract. In many cases the signs of secondary respiratory infection start to show up only when the victim seems to be getting back to health. That is why medical treatment should not be stopped as soon as the victim starts getting better. The symptoms associated with the secondary respiratory infection include:
  • intense chills,
  • productive cough,
  • high fever
  • chest pains associated with breathing.
Flu may also aggravate other chronic diseases such as heart and lung problems.

Influenza symptoms