What Is Shigellosis?

Shigellosis is an infectious disease caused by a group of bacteria called Shigella. The disease itself is commonly referred to as dysentery. People are the only source for Shigella bacteria.  It is extremely infectious, and ingestion of 10 organisms is enough to cause symptoms. Symptoms tend to occur within 1-3 days after ingestion.


What are the signs and symptoms of Shigellosis?

Most people who are infected with Shigella develop diarrhea, fever and stomach cramps starting a day or two after they are exposed to the bacteria. The diarrhea is often bloody. Some individuals may have only mild infection or no symptoms at all. The illness lasts an average of 5-7 days.  In some cases the symptoms can be quite severe and last for several days or weeks.

The disease is sometimes more severe in children than it is in adults and in some cases there is an association with Hemolytic Uremic Syndrome (HUS), a leading cause of kidney failure in both young children and the elderly. Symptoms of HUS include irritability, fatigue, paleness of the skin, puffiness around the eyes and ankles, and decreased urine production. Anyone can become ill with shigellosis but the elderly, malnourished and young children are considered to have an increased susceptibility.


How Is Shigellosis Spread?

Shigella lives in the intestines of infected people. Most Shigella infections are the result of the bacterium passing from stools or soiled hands of one person to the mouth of another person (fecal-oral transmission). It takes very few organisms to cause illness. As a result, person-to-person spread between family members is common. Shigella infections can be acquired from eating contaminated food or drinking polluted water. Food may become contaminated when infected food handlers do not wash their hands properly after using the bathroom. Water may become contaminated if sewage runs into it.  Vegetables irrigated with contaminated water and shellfish harvested from contaminated water may also spread Shigella bacteria.  Flies can spread disease by being in contact with infected feces and then landing on uncovered food.


How Do You Prevent Shigellosis Infection?

  • Thorough hand washing is the best prevention. Proper hand washing includes soap and water for at least 15 seconds. Make sure hands are washed after using the toilet and changing diapers and before handling and eating foods.
  • Infected people should not work as food handlers or care providers until they are clear of the infection.
  • Drink water from a safe supply. When travelling, use bottled water or boil the water for at least 5 minutes if the water supply is unknown. Remember that ice cubes can also be contaminated. Avoid swimming in water that may be contaminated.
  • Avoid eating raw shellfish harvested from unknown sources.
  • Protect food against flies and cockroaches by keeping it covered.
  • Wash all fruits and vegetables before use.


This page provides basic information only. It must not take the place of medical advice, diagnosis or treatment. Always talk to a health care professional about any health concerns.


For Further Information

Call the Infectious Disease Program: (807) 625-5900

or toll-free 1-888-294-6630

Health Topic
Diseases & Infections