Which disease is caused by Shigella bacteria?

Shigella bacteria cause shigellosis, an intestinal infection also known historically as bacillary dysentery.

Shigella spreads mainly by the fecal–oral route, through contaminated food, water, hands, surfaces, or close personal contact. It invades cells lining the large intestine, producing diarrhea, fever, abdominal cramps, and sometimes blood or mucus in the stool. Symptoms commonly begin within a few days of exposure.

The genus contains four commonly recognized groups: Shigella sonnei, S. flexneri, S. boydii, and S. dysenteriae. S. sonnei is especially common in the United States, while S. dysenteriae can cause severe outbreaks. A notable feature is the bacterium’s very low infectious dose: ingestion of only a small number of cells may cause illness.

Shigellosis is often confused with amoebic dysentery or cholera, but those diseases have different causes. Most cases improve with fluids and rest; antibiotics may be used for severe infections, although drug resistance is an increasing concern.