The flu is a viral infection caused by one of two groups of influenza viruses, A (strains H1N1, H3N1, H5N1) and B.

In susceptible people, these viruses (very important point: not everyone infected gets sick) cause the following symptoms: chills/fever, sore throat, muscle aches, fatigue, cough, headache, and runny or stuffy nose.

If you look at these symptoms, they sound like a bad cold. Most people who get the flu get better without need for acute or supportive, in-hospital medical treatment.

Staying home, getting hydrated, taking vitamin C and Tylenol for the aches and pains, and rest will cure most cases of flu.