Public Health Fact Sheet

What is Giardiasis?
Giardiasis is a diarrheal illness that is caused by ingesting the parasite giardia. Giardia can be found on surfaces or in soil, food and water that has been contaminated with feces.

How is Giardiasis spread?
Giardiasis can be spread in many different ways but is most commonly transmitted through water.  Giardiasis can also be transmitted person-to-person by infected people who do not wash their hands after having a bowel movement or after changing soiled diapers.

How long after exposure until symptoms begin?
Symptoms usually begin 1-3 weeks after exposure.  Symptoms can last as long as 2-6 weeks.  Treatment can shorten the amount of time the symptoms last.

How is Giardiasis treated?
If you have this disease, your doctor can prescribe medication.  Make sure finish the medicine completely. A stool sample will be tested after finishing your treatment to ensure you are free of parasites.  Drink plenty of fluids to prevent dehydration due to fluid loss during  diarrhea.

How can Giardiasis be prevented?
Practice good hygiene and always wash your hands after going to the toilet and before preparing food. Prompt and proper treatment will help stop the spread of the parasite to other family members or in day care centers.  Do not drink water from streams or lakes.

Additional information is available on the CDC website at
Symptoms of Giardiasis

  • Frequent, loose and pale greasy stools
  • Stomach cramping and pain
  • Fatigue

  • Severe bloating
  • Weight loss
February 2020