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Giardiasis is a diarrheal illness caused by a one-celled, microscopic parasite, Giardia intestinalis (also known as Giardia lamblia). Once an animal or person has been infected with Giardia intestinalis, the parasite lives in the intestine and is passed in the stool. Because the parasite is protected by an outer shell, it can survive outside the body and in the environment for long periods of time.
During the past 2 decades, Giardia infection has become recognized as one of the most common causes of waterborne disease (found in both drinking and recreational water) in humans in the United States . Giardia are found worldwide and within every region of the United States.
Giardia infection can cause a variety of intestinal symptoms, which include
These symptoms may lead to weight loss and dehydration. Some people with giardiasis have no symptoms at all.
Symptoms of giardiasis normally begin 1 to 2 weeks (average 7 days) after becoming infected. In otherwise healthy persons, symptoms of giardiasis may last 2 to 6 weeks. Occasionally, symptoms last longer.
Your health care provider will likely ask you to submit stool samples to check for the parasite. Because Giardia can be difficult to diagnose, your provider might ask you to submit multiple stool specimens collected over a few days.
The Giardia parasite lives in the intestine of infected humans or animals. Millions of germs can be released in a bowel movement from an infected human or animal. Giardia is found in soil, food, water, or surfaces that have been contaminated with the feces from infected humans or animals. You can become infected after accidentally swallowing the parasite; you cannot become infected through contact with blood. Giardia can be spread by:
Several prescription drugs are available to treat Giardia . Although Giardia can infect all people, young children and pregnant women may be more susceptible to dehydration resulting from diarrhea and should, therefore, drink plenty of fluids while ill.