The flu, also known as influenza, is an extremely common viral infection of the respiratory system. It is important for certain people to avoid the virus including children, the elderly, pregnant women, those who have compromised immune systems and the people who live with and care for them. Symptoms of the flu include fever, muscle soreness, chills and sweats, fatigue, congestion, cough and sore throat. While flu symptoms are generally present for about a week, the danger of the flu is from complications that can arise, especially for at-risk individuals. Influenza is treatable with medication if identified within the first 48 hours of illness, but if treatment is delayed the recommendation is generally rest and ample fluids. Seek medical care for influenza symptoms if you are at risk for complications, if you experience chest pains, difficulty breathing or swallowing, become dehydrated or if you have a fever that is extreme or persists for more than a few days. The best treatment for the flu is prevention with an annual flu shot.