Causes

Infection occurs when you accidentally swallow shigella bacteria. This can happen when you:

• Touch your mouth. Direct person-to-person contact is the most common way the disease is spread. For example, if you don't wash your hands well after changing the diaper of a child who has shigella infection, you may become infected yourself.
• Eat contaminated food. Infected people who handle food can spread the bacteria to people who eat the food. Food can also become infected with shigella bacteria if it grows in a field that contains sewage.
• Swallow contaminated water. Water may become infected with shigella bacteria either from sewage or from a person with shigella infection swimming in it.