The common name for the disease caused by the influenza virus is the "flu." Influenza is a contagious respiratory illness characterized by symptoms such as fever, cough, sore throat, body aches, and fatigue. It can affect people of all ages, with particular severity in young children, the elderly, and those with weakened immune systems. The flu spreads primarily through respiratory droplets when an infected person coughs or sneezes. Vaccination is a key preventive measure, and antiviral medications can help reduce the severity and duration of illness when administered promptly.