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Facts About...


What is it?

Shigellosis is an infectious disease of the gastrointestinal tract and is caused by a group of bacteria called Shigella. Very few bacteria (10-100) are required to cause illness. In some people, especially young children and the elderly, diarrhea can be very severe and require hospital admission. Outbreaks of shigellosis are common among children who are not toilet trained, and under conditions of overcrowding when personal hygiene is poor or food handling and water quality is poor. For example, outbreaks are known to occur in jails, institutions for child care, and day care centres.

Shigellosis is a reportable disease and must be reported to the Health Department.

How is it spread?

Shigella bacteria are found in the stool (feces) of an infected person while they are sick until up to two weeks afterwards. The bacteria are spread to others when hands are not properly washed after using the washroom. Bacteria on the hands can then be spread to food, water, objects or the hands of another. Because it takes so few bacteria to cause illness, spread between family members (called person-to-person spread) is common.

Contaminated food is another source of Shigella infections. Food may become contaminated when touched by unwashed hands of an infected food handler. Alternatively, food may become contaminated during production (i.e., when it is grown using contaminated water or sewage), or when flies that breed in sewage land on unprotected food. Drinking water and water used for bathing or swimming that is contaminated by sewage can also cause Shigella infections.

What do I look for?

Symptoms of Shigellosis include diarrhea that may be bloody, fever, nausea, vomiting, and stomach cramps. Symptoms generally occur 1 to 3 days after ingestion of the bacterium, and last 4 to 7 days. Some cases have very mild symptoms or no symptoms at all but can still spread the Shigella bacteria to others. Illness is usually more severe in children and the elderly. It is associated with Hemolytic Uremic Syndrome (HUS), a main cause of kidney failure in young children.

How can I protect myself?

  • Frequent and thorough handwashing is the best way to prevent the spread of Shigella. Every time after using the washroom or handling diapers, ensure that hands are washed with warm water, soap, and are dried using a single-use towel. Also wash hands before eating and preparing food
  • Infected people and ill contacts should not handle food or provide child/patient care until diarrhea ceases and tests indicate that they are no longer carrying the Shigella bacterium
  • Diaper change areas should be cleaned and disinfected after use. Dispose of soiled diapers properly. Children with diarrhea should not attend childcare settings
  • Private well water should be tested for bacteria four times a year. The Health Department supplies sample bottles for testing, and will assist with interpretation of the test results
  • Always drink water from a safe supply. Boil water for one minute or use bottled water if you are unsure of the supply
  • Avoid swimming in water that may be contaminated
  • Avoid eating shellfish such as clams, crabs, oysters, or mussels that have been exposed to sewage
  • If you are travelling to developing countries, "boil it, cook it, peel it, or forget it"

More information can be obtained from

Durham Region Health Department, Environmental Help Line 905-723-3818 or 1-888-777-9613

April 22, 2013

For more information call
905-668-7711 OR 1-800-841-2729