• Flu (Influenza)
• What Is It? & Symptoms
• Diagnosis & Expected Duration
• Prevention & Treatment
• More Info

What Is It?

Influenza, usually known as the flu, is a respiratory infection caused by the influenza virus. The infection typically is spread by air or by direct contact, from one person to another. Most cases occur during epidemics, which peak during the winter months nearly every year. Influenza virus is very contagious. A particularly widespread and severe epidemic is called a pandemic.

Compared with other viruses, influenza can strike remarkably large numbers of people in a relatively short...