What causes influenza?

Flu is caused by a virus in the body. It spreads when infected persons cough, sneeze, or even talk around others. People with flu are contagious a day before symptoms appear and three to seven days after. Children can be contagious for more than a week. You can get the flu simply by touching a surface like a telephone or doorknob that has been contaminated by a touch from someone who has the flu. The viruses can pass through the air and enter your body through your nose or mouth. If you have touched a contaminated surface, they can pass from your hand to your nose or mouth.

There are three types of influenza viruses. Type A is the most common flu. It changes often and causes a new epidemic, or mass outbreak of flu, every few years. An epidemic usually peaks within 2 or 3 weeks after the first cases occur. Type B causes smaller, local or regional outbreaks and Type C causes only mild illness.

To learn more:

Colds and the Flu: Prevention
This consumer health site from the American Association of Family Physicians gives good advice about coping with influenza and gives a simple explanation on what causes flu.
Influenza (Flu): Causes
This page from the Mayo Clinic’s influenza section explains the causes of flu. Scroll down for "Causes". Click on other sections of the article for information about symptoms, risk factors, treatment, and prevention.

next » What are the signs and symptoms of influenza?

Last Modified: Tuesday November 05, 2019 10:58 AM