Giardiasis Fact Sheet

Minnesota Department of Health
Revised May, 2009

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Giardia Fact Sheet (PDF: 32KB/1 page)

What is it?

Giardia is a parasite that causes a diarrheal illness called giardiasis. Giardiasis is one of the most common waterborne diseases in the United States and is frequently found in both drinking water and recreational water.

What are the symptoms?

Symptoms of giardiasis include diarrhea, gas, stomach cramps and bloating, nausea, loss of appetite, and weight loss. Sometimes people infected with Giardia have no symptoms at all, but can still pass the parasite to others. This is especially common in children.

Symptoms usually begin 1 to 2 weeks after being exposed to the parasite, but may appear as late as 4 weeks after exposure.

How long does it last?

In healthy people, symptoms can last from 2 to 6 weeks. Treatment for giardiasis is available from your health care provider.

How is it spread?

Giardia can be found in water, food, soil, or surfaces that have been contaminated with the feces of infected humans or animals. Giardia can survive for long periods of time outside the body and in the environment. You can become infected with Giardia after accidentally swallowing the parasite.

People become infected with Giardia by:

  • Swallowing recreational water contaminated with Giardia (recreational water includes lakes, streams, rivers, springs, ponds, swimming pools, hot tubs, Jacuzzis, and water park fountains).
  • Eating food or drinking liquids contaminated with Giardia.
  • Touching contaminated surfaces or objects and then touching their mouth or putting a contaminated object into their mouth.
  • Not washing hands after using the bathroom or changing diapers and then eating foods.

What should I do if I have symptoms?

  • Contact your health care provider.
  • Wash your hands often.

How can I prevent Giardia infections?

  • Wash your hands with warm, soapy water for 20 seconds
    • After using the bathroom
    • After changing diapers
    • After touching animals
    • Before eating
    • Before preparing food
      • Wash your hands more often when someone in your household is sick.
  • Don’t drink untreated water from lakes, rivers, streams, ponds, or unsafe wells.
    See Bacterial Safety of Well Water for more information about unsafe wells.
  • Wash and/or peel fruits and vegetables before eating them. 
  • Avoid preparing food for others while you have symptoms.
  • Clean and disinfect surfaces with household bleach immediately after vomiting or diarrheal accidents.

Healthy Swimming Tips:

  • Do not swallow water or get water in your mouth while swimming.
  • Take a shower before and after swimming.
  • Do not swim when you have diarrhea.  You can pass Giardia in your stool and contaminate water for several weeks after your symptoms have ended.
  • When swimming, take kids on frequent bathroom breaks – waiting to hear “I have to go” may mean that it’s already too late.
  • Change diapers in changing rooms, not poolside or on the beach. Wash hands after changing diapers.

Updated Tuesday, November 16, 2010 at 12:21PM