Although health experts don't know why, some people take in Shigella bacteria without becoming ill. Others develop only a brief fever, or a brief fever with mild diarrhea that goes away on its own. About 25% of patients, however, develop high fever, abdominal cramping and severe diarrhea that can contain blood, mucus and pus. These people can have 10 to 30 bowel movements each day, along with a persistent urge to have a bowel movement.
Rarely, Shigella bacteria can affect other parts of the body far from the digestive tract. When this happens, there may be a rash, joint pain, confusion and/or kidney failure.