Shigellosis

Click here for a PDF “print-friendly” version of this fact sheet

What is shigellosis?

Shigellosis is an acute bacterial disease that causes diarrhoea, often bloody diarrhoea, accompanied by fever, nausea and sometimes vomiting and cramps. The disease is commonly referred to as dysentery. Some cases can be quite severe and symptoms can last for several days or several weeks, with an average of 4 – 7 days. The disease is more severe in children than in adults and is associated with Hemolytic Uremic Syndrome (HUS), a leading cause of kidney failure in the elderly and young adults. Symptoms of HUS include irritability, fatigue, paleness of the skin, puffiness around the eyes and ankles, and a decrease in the amount of urine produced.

How is it spread?

People are the only significant hosts for shigella bacteria. The bacteria are found in the intestines of infected people. Infection can occur after the ingestion of very few organisms (10-100). People who go to the bathroom and do not wash their hands properly can pass the disease to others directly by physical contact (touching) or indirectly through food preparation. Because it takes so few organisms to cause illness, person-to-person spread between family members is common. Shigellosis can also be spread by drinking water contaminated by sewage. Flies may also transfer the organism on their feet after being in contact with infected faeces and then landing on uncovered food left unrefrigerated. Avoid eating raw shellfish, such as clams, crabs, oysters, or mussels, that has been exposed to sewage. Many seaport cities worldwide let the tides carry their sewage out into the ocean where shellfish become contaminated.

How is it prevented?

• Thorough hand washing is the best prevention. Make sure hands are properly washed after using the toilet and handling diapers.
• Small numbers of bacteria are required to cause illness, so infected people should not work as food handlers or provide childcare until they are shigella free.
• Do not eat raw shellfish.
• Drink water from a safe supply.
• Boil water for at least 5 minutes or drink bottled water when travelling if you are unsure of the supply. Remember that ice cubes could also be contaminated.
• Avoid swimming in water that may be contaminated.

For more information please call Public Health at 519-376-9420 or 1-800-263-3456.

Reprinted from the Canadian Institute of Public Health Inspectors (CIPHI)