Shigellae are gram-negative, nonmotile, non-spore-forming, rod-shaped bacteria capable of causing disease in humans. Disease occurs when Shigella organisms are consumed and invade the intestinal lining, resulting in tissue destruction. The disease is contracted through oral contact with anything that has been contaminated with the organism, usually through fecal matter; this includes food, water, surfaces, contaminated swimming pools, utensils, equipment, unwashed hands, etc. Some Shigella strains produce toxins. Shigella poisoning, also known as "shigellosis," is typically self-limiting and treatable, and most people recover quickly.
Typically symptoms are diarrhea, fever, nausea, vomiting, and stomach cramps. In cases of dysentery, the stool may contain blood, mucus, or pus. Symptoms can begin two to four days after ingestion, but can take as long as a week to occur.
