What is Giardia infection?
Giardia is a microscopic parasite that causes the diarrheal illness known as giardiasis.

Drinking from Stream
How common is Giardia infection? 
Approximately 450 cases of giardiasis are reported in Colorado each year. Cases occur more commonly in the summer and fall. Giardiasis has a worldwide distribution. Children are infected more frequently than adults. More cases occur in areas of poor sanitation and in institutions with children who are not toilet trained, such as child care centers.

What are the symptoms of Giardia?
Symptoms begin 3-25 days (usually 7-10 days) after ingesting the Giardia parasite. Symptoms include:

  • Diarrhea and greasy stools (feces)
  • Stomach cramping, bloating and passing gas
  • Fatigue, loss of appetite and weight loss
  • Symptoms may last 2-6 weeks, they may come and go, and occasionally last longer

Kids in Daycare
How is Giardia spread?
Giardia is found in the stool of infected humans, wild animals and pets.  Giardia spreads when infected people do not wash their hands thoroughly after using the bathroom or from having contact with ill people.  People with Giardia infection who go swimming when they have diarrhea can contaminate recreational water such as lakes or rivers, as well as swimming pools. Animals with Giardia infection also can contaminate water. Giardia infection can come from swallowing contaminated water.  Travelers to countries where Giardia is common can get infected as described above.

When to call your healthcare provider
Contact your healthcare provider if you have diarrhea that has lasted for over 3 days, or if you have a high fever, have blood in your stool, or if you are becoming dehydrated from having diarrhea and/or vomiting.

How is Giardia diagnosed?
Your healthcare provider will ask you to submit a stool  sample and run laboratory tests to see if you are infected.

How is Giardia infection treated?
Most people with mild Giardia infection get better on their own.  Medications prescribed by your doctor may shorten the illness.

How do I avoid Giardia infection?

  • Practice good hygiene.  Wash hands thoroughly with soap and water after using the toilet, before handling or eating food, after changing diapers.
  • Avoid drinking untreated water from shallow wells, lakes, rivers, springs, ponds, and streams.  Avoid swallowing recreational water as well.
  • Be aware of risks associated with drinking water from certain areas when traveling.
  • Protect others by not swimming if you are experiencing diarrhea.
  • Wash and peel raw vegetables and fruits before eating.

Is there anything special I need to know?

  • Wash your hands after you use the bathroom
  • Do not prepare food for others while ill.
  • Ill persons who work in food service or in child care should not return to work until 24 hours after diarrhea has stopped.
  • Children who have Giardia should not go to child care settings until 24 hours after diarrhea has stopped.
  • Do not go swimming when you have diarrhea.

Why does public health investigate Giardia cases?
It is the responsibility of the local health department to investigate Giardia in the community. The health department keeps track of how many people are reported to have the disease and works to limit the number of people exposed.  

Most people infected with Giardia are single, sporadic cases. However, sometimes there are outbreaks when two or more people become ill from the same source. The health department monitors Giardia in an attempt to identify and stop outbreaks of the disease.  

Larimer County Department Health and Environment is part of a Centers for Disease Control and Prevention monitoring system that studies what puts people at risk for getting Giardia.