The species of the genus Shigella are very similar by all methods of comparison with those of the genus Escherichia. . This microbe is a Gram negative, rod-shaped bacterium which is one of the world’s most common causes of the gastrointestinal disease called shigellosis or bacterial dysentery (characterized by bloody diarrhea), responsible for over 100,000,000 cases and at least 100,000 deaths annually. Shigella dysenteriae is the most common cause of epidemics of shigellosis worldwide, particularly in crowded conditions with poor sanitation available. Complications can include rectal prolapse, joint pain, and a variety of other issues. It is also associated with Hemolytic Uremic Syndrome which can result in renal failure. Victims can be humans and other primates, with occasional reports of infections in other mammals. Source of infection is fecal-oral, typically from contaminated water or food. The rods are straight and nonmotile (unlike Escherichia spp.). And unlike most members of the Enterobacteriaceae they do not produce gas when fermenting sugars. Growth occurs optimally at 35-37 C.