Shigellosis is an important cause of diarrheal disease and bloody diarrhea worldwide. It most commonly affects children <5 years old.
Infection is easily spread by fecal-oral contact or by contaminated water or food. Outbreaks may occur in areas with overcrowding and poor sanitation.
There are 4 species of causative organism: Shigella sonnei , S flexneri , S boydii , and S dysenteriae . S sonnei and S flexneri are most common in Western countries, with S sonnei causing a mild, self-limited illness.
S dysenteriae is more common in developing countries and causes a more severe illness with dysentery. S dysenteriae type 1 is also a cause of hemolytic-uremic syndrome owing to its production of Shiga toxin.
Treatment is usually supportive in mild cases, although antibiotics may be useful to shorten the course of the illness and reduce shedding of the organism in stool, particularly in patients with bloody diarrhea. Empiric antibiotics are recommended for children and adults with severe disease, for older adults, for malnourished or chronically ill patients, and to reduce spread (e.g., in institutions).
Prevention is paramount, including basic hygiene measures such as hand-washing with soap, access to clean water, and cooking, especially in institutions and camps during natural disasters. Vaccinations are still in developmental stages.
Shigellosis is an important cause of diarrheal disease worldwide, most commonly affecting children <5 years old. However, about 40% of cases are in adults.  Shigella is a genus of the Enterobacteriaceae family, consisting of 4 species of aerobic, nonmotile, non-lactose-fermenting gram-negative rods: S sonnei , S flexneri , S boydii , and S dysenteriae . Shigellosis may spread from person to person (by fecal-oral contact), and via contaminated water and food. Outbreaks also occur in institutions and in overcrowded areas where sanitation is poor. Although not equivalent, the term "bloody diarrhea" is sometimes used interchangeably by clinical practitioners.
Department of Gastroenterology
John Radcliffe Hospital
SK declares that he has no competing interests.
Consultant Hepatologist and Gastroenterologist
St Mark's and Northwick Park Hospitals
AB declares that he has no competing interests.
Dr Satish Keshav and Dr Ashley Barnabas would like to gratefully acknowledge Dr Gehanjali D.A. Amarasinghe and Dr Richard Pollok, the previous contributors to this monograph. GDAA and RP declare that they have no competing interests.
Chief Medical Officer
Director of Food Safety and Security
US Food and Drug Administration
DA declares that he has no competing interests.
Professor of Clinical Microbiology
Austrian Agency for Health and Food Safety (AGES)
FA declares that he has no competing interests.
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