Shigellosis is caused by a group of bacteria called Shigella.
There are several types of Shigella bacteria, including.
Shigella sonnei, also called "group D" Shigella, is responsible for most cases of shigellosis in the United States.
Shigella flexneri, or "group B" Shigella, causes almost all other cases.
Shigella dysenteriae, or "group A" Shigella is rare in the U.S., but can lead to deadly outbreaks in developing countries.
People infected with the bacteria release it into their stool. They can spread the bacteria to water or food, or directly to another person. Getting just a little bit of the Shigella bacteria into your mouth is enough to cause infection.
Outbreaks of shigellosis are linked with poor sanitation, contaminated food and water, and crowded living conditions.
Shigellosis is common among travelers in developing countries and workers or residents in refugee camps.
In the U.S., the condition is most commonly seen in day care centers and places where groups of people live, such as nursing homes.
Symptoms usually develop about 1 to 7 days (average 3 days) after coming into contact with the bacteria.
The goal of treatment is to replace fluids and electrolytes (salt and minerals) that are lost in diarrhea.
Medications that stop diarrhea are generally not given, because they can cause the infection to take longer to go away.
Self-care measures to avoid dehydration include drinking electrolyte solutions to replace the fluids lost by diarrhea. Several varieties of electrolyte solutions are available over the counter (without a prescription).
Antibiotics can help shorten the length of the illness and help prevent it from spreading to others in group living or day care settings. They may also be prescribed for patients with severe symptoms.
If you have diarrhea and cannot drink fluids by mouth because of severe nausea, you may need medical attention and fluids through a vein (IV, or intravenously). This is especially common in small children who have shigellosis.
People who take diuretics ("water pills") may need to stop taking these medicines if they have acuteShigella enteritis. Never stop taking any medicine without first talking to your health care provider.
The infection is often mild and goes away on its own. Most patients, except malnourished children and those with weakened immune systems, recover fully.
About 1 in 10 children with severe Shigella enteritis develop neurological problems, including febrile seizures (also called a "fever fit") when body temperature rises quickly and the child has seizures, or a brain disease (encephalopathy) with headache, lethargy, confusion, and stiff neck.
When to Contact a Medical Professional
Call your health care provider if diarrhea does not improve, if there is blood in the stool, or if there are signs of dehydration.
Go to the emergency room if these symptoms occur in a person with shigellosis:
Headache with stiff neck
These symptoms are most common in children.
Prevention includes properly handling, storing, and preparing food, and good personal hygiene. Hand washing is the most effective way to prevent shigellosis. Avoid food and water that may be contaminated.
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Semrad CE. Approach to the patient with diarrhea and malabsorption. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap142.
Giannella RA. Infectious enteritis and proctocolitis and bacterial food poisoning. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger & Fordtran's Gastrointestinal and Liver Disease. 9th ed. Philadelphia, PA: Elsevier Saunders; 2010:chap 107.
Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.