Shigellosis is caused by a group of bacteria called Shigella.
There are several types of Shigella bacteria, including.
- Shigella sonnei, also called "group D" Shigella, is responsible for most cases of shigellosis in the United States.
- Shigella flexneri, or "group B" Shigella, causes almost all other cases.
- Shigella dysenteriae, or "group A" Shigella is rare in the U.S., but can lead to deadly outbreaks in developing countries.
People infected with the bacteria release it into their stool. They can spread the bacteria to water or food, or directly to another person. Getting just a little bit of the Shigella bacteria into your mouth is enough to cause infection.
Outbreaks of shigellosis are linked with poor sanitation, contaminated food and water, and crowded living conditions.
Shigellosis is common among travelers in developing countries and workers or residents in refugee camps.
In the U.S., the condition is most commonly seen in day care centers and places where groups of people live, such as nursing homes.