A case of shigellosis is caused by one of the four serogroups of Shigella bacteria, and is most often manifested by diarrhea, fever, nausea, and sometimes vomiting. A case of shigellosis may be considered confirmed or probable. A confirmed case has been proven by laboratory testing, while a probable case is symptomatic and can be epidemiologically linked to a confirmed case. Both of these types of cases are counted in the reported case counts.
