shigellosis, infection of the gastrointestinal tract by bacteria of the genus Shigella. The illness produces cramplike abdominal pain as well as diarrhea consisting of either watery stools or scant stools containing mucus and blood. Fever and dehydration are other common symptoms. Shigellosis occurs throughout the world, especially where overcrowding is a problem and personal hygiene is poor.
Shigellosis can be transmitted directly, via the fecal-oral route, or indirectly, by ingestion of contaminated food or water or by contact with fomites (inanimate objects, such as clothing, that can convey infection). Asymptomatic humans may be carriers. In most individuals, once the pathogen is inside the body, very few organisms are needed to produce illness.
Diagnosis of shigellosis is made by stool cultures. Treatment with appropriate antibiotics shortens the duration of the illness and eliminates the Shigella organism from the stool, thereby limiting further transmission of the disease. See also dysentery.