You can be infected with Shigella by
Ingestion of an extremely low number of bacteria, 10 to 100, can cause infection. If you are infected with Shigella, you can still pass the bacteria to others even if you have no symptoms of shigellosis. Toddlers and small children under the age of five are at highest risk for infection with shigellosis; many cases are spread in child daycare settings or among families with small children.
Last Updated January 19, 2012