what is the influenza
What is Influenza (also called Flu)? The flu is a contagious respiratory illness caused by influenza viruses that infect the nose, throat, and sometimes the lungs. It can cause mild to severe illness, and at times can lead to death. The best way to prevent the flu is by getting a flu vaccine each year. Signs and Symptoms of Flu People who have the flu often feel some or all of these signs and symptoms that usually start suddenly, not gradually: