It is a viral disease of the respiratory tract. Each type includes many different strains that tend to change each year.
Influenza occurs most often in the late fall and winter months.
Influenza is highly contagious and is easily spread through contact with droplets from the nose and throat of an infected person during coughing and sneezing. Typical flu symptoms include headache, fever, chills, cough, sore throat and body aches. Diarrhea and vomiting are not common. Although most people are ill for a week or less, some people may have a more serious illness and need to be hospitalized. Symptoms usually appear in 1 to 3 days.