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Influenza
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Influenza, also called the flu, is a respiratory infection caused by influenza viruses. Picture the path air takes: the viruses can infect tissue in the nose, continue into the throat, and sometimes reach the lungs. Influenza is therefore an illness of the respiratory system, not just a general feeling of being unwell.
It often begins suddenly with some combination of cough, sore throat, congestion, muscle aches, headache, fatigue, and sometimes fever or chills. That combination can resemble other infections.
In brief
Influenza, or the flu, is a contagious respiratory illness caused by influenza viruses. These viruses infect tissues in the nose, throat, and sometimes the lungs, so influenza is an illness of the respiratory system rather than just a general feeling of being unwell.
Symptoms often begin suddenly and may include fever or chills, cough, sore throat, congestion, muscle aches, headache, and fatigue. The combination can vary, and individual symptoms alone cannot distinguish influenza from other respiratory infections.
Sources (1)
- Centers for Disease Control and PreventionAbout InfluenzaPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
Updated