Flu
Flu, also known as influenza, is a contagious respiratory illness caused by a virus. It can cause mild to severe symptoms, including fever, muscle aches, sore throat, cough, and congestion. Complications of flu can include pneumonia, ear and sinus infections, and worsening of chronic conditions, such as asthma and congestive heart failure. Flu season typically runs from October through May. Vaccination is the best way to prevent flu.