Symptoms of shigellosis usually appear after an incubation period of one to three days. The diarrhoea may be watery and of a large volume initially, but then changing into frequent, small-volume episodes of bloody and mucoid (mucus-containing) diarrhoea. The onset of the disease is sudden, with fever, abdominal pains, straining during defaecation and an irresistible urge to defaecate, but only small quantities of blood and mucus come out, without any formed solid stools. The person may complain of abdominal cramps and pain in the rectum, and is often too ill to leave their bed. Dehydration can progress quickly and may lead to shock and death if not rapidly treated.