Those infected with the bacteria release it into their stool, thus causing possibility of spread through food or water, or from direct contact to a person orally.

Having poorly sanitized living conditions or contaminated food or water contributes to contracting the disease.

[8] Infants and toddlers, the elderly, and people living with chronic health conditions are all susceptible to the most severe symptoms of S. sonnei disease.

Shigellosis may invade the bloodstream and cause bacteremia in people with a compromised immune system, which can be life-threatening.

[8] Most Shigella infection usually clears up without complications, but if left untreated or delay in diagnosis may lead to some serious complication such as dehydration (especially severe dehydration can lead to shock and death), seizure, hemolytic uremic syndrome (HUS), toxic megacolon, and reactive arthritis.