shigellosis /shig′əlō″sis/ [Kiyoshi Shiga, Gk, osis, condition] , an acute, highly contagious bacterial infection of the bowel with a low infectious dose (as few as 180 organisms), characterized by diarrhea, abdominal pain, and fever. It is transmitted by hand-to-mouth contact with the feces of individuals infected with bacteria of a pathogenic species of the genus Shigella. Damage is caused by invasion of bacteria (which is dependent on a plasmid-mediated virulence factor) and production of the enterotoxin Shiga toxin. These organisms may be carried in the stools of asymptomatic people for up to several months and may be spread through contact with contaminated objects, food, or flies, especially in poor, crowded areas. The disease occurs in isolated outbreaks in the United States but is endemic in underdeveloped areas of the world. It is especially common and usually most severe in children. Diagnosis is made by isolating and identifying Shigella in a specimen of stool. The likelihood of encountering or engendering antibiotic-resistant organisms is very high. Therefore the preferred treatment for shigellosis is supportive, and the major goal is prevention of dehydration. Antimicrobials are given if the disease is severe or if the likelihood of further transmission is great. Antidiarrheal agents should be avoided. Isolation and strict handwashing precautions are instituted. Shigellosis infections must be reported to the public health department. Also called bacillary dysentery.
