The species of the genus Shigella are very similar by all methods of comparison with those of the genus Escherichia. This species is an uncommonly encountered pathogen in the US but is a huge problem in developing nations. It is a Gram negative, rod-shaped bacterium which is associated with gastrointestinal disease called shigellosis or bacterial dysentery, characterized by bloody diarrhea. 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 ssp.). And unlike most members of the Enterobacteriaceae they do not produce gas when fermenting sugars. Growth occurs optimally at 35-37 C.