Influenza is a highly infectious viral disease that affects mainly the nose, throat, bronchi and, occasionally, lungs. It is a contagious illness characterized by fever, headaches, sore throat, body aches and congestion of the nose. Influenza can also lead to pneumonia and death especially among children, the elderly, and those with serious medical condition. The virus is transmitted easily from person to person via droplets and small particles produced when infected people cough or sneeze. Influenza tends to spread rapidly in seasonal epidemics.