Giardiasis is an intestinal illness that causes
diarrhea. In fact, it is the most common nonbacterial cause of diarrhea in the United States
(see Diarrhea Causes). Giardiasis is also one of the most common illnesses worldwide, affecting up to 20 percent of the world's population. Giardiasis is most prevalent in developing countries, where infections are often associated with poor sanitary conditions.
Giardiasis is more common in children than in adults. However, chronic giardiasis is more common in adults.
Giardiasis is caused by a one-celled, microscopic parasite called
Giardia intestinalis (or
Giardia lamblia). This parasite was initially named
Cercomonas intestinalis and renamed
Giardia lamblia in 1915. However, many consider
Giardia intestinalis to be the correct name for this parasite.
Transmission of Giardiasis
Giardia is found in:
- Soil
- Food
- Water
- Surfaces that have been contaminated with feces from infected humans or animals.
Giardiasis transmission can occur by accidentally swallowing the parasite; you cannot become infected with Giardia through contact with blood.
When a person becomes infected with
Giardia, the parasite begins to multiply within the intestines. After one to two weeks (the average is seven days), symptoms of giardiasis can occur. Symptoms may begin gradually or come on all of a sudden. Symptoms will also vary among individuals.
Common symptoms of giardiasis can include:
- Diarrhea
- Gas or flatulence
- Bloating
- Vomiting
- Greasy stools that tend to float
- Abdominal pain
- Belching
- Stomach cramps
- Upset stomach or nausea.
These symptoms may lead to weight loss and dehydration.
(Click Giardia Symptoms for more information about symptoms associated with this condition.)
In order to make a giardiasis diagnosis, the doctor will generally begin by asking a number of questions, including information about symptoms, current medicines, and medical conditions, along with your recent travel history. The doctor will also likely perform a physical exam and recommend certain tests.
As part of testing for Giardia, your healthcare provider will likely ask you to submit stool samples. Because giardiasis can be difficult to diagnose, your provider may ask you to submit several stool specimens over a period of days.
Several prescription medicines are available for
giardiasis treatment (see Giardia Medication). These medicines cure giardiasis in about 80 percent of people. If a person's symptoms do not improve with treatment, the doctor may recommend another medication or the same medicine for a longer period of time.
Treatment for giardiasis also involves staying well hydrated and possibly treating people who have had close contact with the infected person.
Who Is at Risk for Giardiasis?
Anyone can get giardiasis. People more likely to become infected include:
- Children who attend daycare centers, including diaper-aged children
- Parents of infected children
- International travelers
- Childcare workers
- People who swallow water from contaminated sources
- Backpackers, hikers, and campers who drink unfiltered, untreated water
- Swimmers who swallow water while swimming in lakes, rivers, ponds, and streams
- People who drink from shallow wells.
Contaminated water includes water that has not been boiled, filtered, or disinfected with chemicals. Several community-wide outbreaks of giardiasis have been linked to drinking municipal water or recreational water contaminated with
Giardia.
There are several things a person can do to prevent giardiasis. Some of these include:
- Practicing good hygiene
- Avoiding water that might be contaminated
- Avoiding food that might be contaminated
- Avoiding fecal exposure during sexual activity.
Other Giardiasis Information
For additional information about giardiasis, click any of the following links:
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