Disease and Illness

Algoma Public Health


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What Is Giardiasis?

Giardia lamblia is a parasite that causes diarrhea in humans. This parasite lives in the intestine of people and animals and is passed in the stool. The parasite is protected by an outer shell (cyst) that allows it to survive outside the body and in the environment for long periods of time.  Giardiasis occurs worldwide and children are infected more often than adults are.


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Sault Ste. Marie: 1-866-892-0172

Blind River: 1-888-356-2551

Elliot Lake: 1-888-211-6749

Wawa: 1-888-211-8074 

Symptoms & Duration: Symptoms include diarrhea, loose, mucousy pale greasy stool, stomach cramps, bloating, severe gas, weight loss, fatigue and dehydration. One in every 25 people carries Giardia without having any symptoms. Symptoms usually last 2-6 weeks, but occasionally become chronic.


Incubation Period: Usually 3 to 25 days or longer, however 7 to 10 days is the most common.


Recovery, Long Term Effects & Immunity: Infection is frequently self-limited however antiparasitic treatment is often prescribed. There is no immunity from re-infection. Usually there are no long-term effects however in severe cases damage to intestinal cells may occur.


How Is Giardiasis Spread?

Giardia lamblia lives in the intestine of infected humans or animals (beavers, muskrats, pets and livestock) and may be found in soil, food, water, or surfaces that have been contaminated with the feces from infected humans or animals.  Giardia can be spread person to person. You can become infected if you swallow the Giardia cysts that have been passed in the feces of an infected person or animal. For example:

  • Swallowing untreated surface water from, lakes, rivers, springs, ponds or streams that could be contaminated with sewage or feces from humans or animals.
  • Swallowing recreational water. Sometimes recreational waters such as swimming pools, hot tubs and jacuzzis can be contaminated too.
  • Eating contaminated foods.

 How Do You Prevent Giardiasis Infection

  • Thorough hand washing is the best prevention.  Make sure hands are properly washed with soap and water after using the toilet or changing diapers, after handling pets or livestock and before preparing any food.
  • Thoroughly wash, with uncontaminated water, all vegetables and fruits you plan to eat raw.
  • Do not drink water directly from rivers, creeks and lakes and whenever you are uncertain whether the water has been properly treated (such as foreign travel).
  • When travelling, camping or hiking or a “boil water” advisory has been issued, bring the water to a full boil for 1 minute. This water should be used for drinking, brushing teeth, rinsing dentures or contact lenses, making ice cubes, washing uncooked fruits and vegetables and recipes requiring water (such as baby formula).   Dishes should be washed with water that has been boiled.
  • Avoid sex that involves anal contact.


Date of Creation: June 1, 2015

Last Modified: June 1, 2015