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Giardiasis(Giardia Infection) Download a print version (PDF - 196 KB, 5 pages)
What is giardiasis?Giardiasis (GEE-are-DYE-uh-sis) is a diarrheal illness caused by a microscopic parasite, Giardia intestinalis (also known as Giardia lamblia or Giardia duodenalis). Once a person or animal has been infected with Giardia, the parasite lives in the intestine and is passed in feces. Because the parasite is protected by an outer shell, it can survive outside the body and in the environment for long periods of time (i.e., months). During the past 2 decades, Giardia infection has become recognized as a common cause of waterborne disease in humans in the United States. Giardia can be found worldwide and within every region of the United States. How do you get giardiasis and how is it spread?The Giardia parasite lives in the intestine of infected humans or animals (e.g., cats, dogs, cattle, deer, and beavers). Millions of germs can be released in a bowel movement of an infected human or animal. Giardia is found on surfaces or in soil, food, or water that has 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:
What are the symptoms of giardiasis?Giardia infection can cause a variety of intestinal signs or symptoms, which include
These symptoms may lead to weight loss and dehydration. Some people with Giardia infection have no symptoms at all. How long after infection do symptoms appear?Symptoms of giardiasis normally begin 1 to 2 weeks (average 7 days) after becoming infected. How long will symptoms last?In otherwise healthy persons, symptoms of giardiasis may last 2 to 6 weeks. Occasionally, symptoms last longer. Medications can help decrease the amount of time symptoms last. Who is most likely to get giardiasis?Anyone can get giardiasis. Persons more likely to become infected include
What should I do if I think I may have giardiasis?Contact your health care provider. How is a Giardia infection diagnosed?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. What is the treatment for giardiasis?Several prescription drugs are available to treat Giardia infection. Although Giardia can infect all people, young children and pregnant women might be more susceptible to dehydration resulting from diarrhea and should, therefore, drink plenty of fluids while ill. Rapid loss of fluids from diarrhea can be especially life threatening to infants. Therefore, parents should talk to their health care providers about fluid replacement therapy options for infants. My child does not have diarrhea, but was recently diagnosed as having Giardia infection. My health care provider says treatment is not necessary. Is this true?Treatment is generally not necessary when your child has no symptoms. However, there are a few exceptions. If your child does not have diarrhea, but does have other symptoms such as nausea, fatigue (feels very tired), weight loss, or a poor appetite, you and your health care provider may wish to consider treatment. The same is true if several family members are ill, or if a family member is pregnant and therefore not able to take the most effective anti-Giardia medications. If my child or I have been diagnosed with giardiasis, should I worry about spreading the infection to others?Yes, Giardia infection can be very contagious. Follow these guidelines to avoid spreading Giardia to others:
If your child is diagnosed with giardiasis, follow these guidelines to help your child avoid spreading Giardia infection to others:
If your child receives child care with other children, work with the child care provider or your local health department to identify steps (e.g., keep your child out of group child care until the giardiasis symptoms resolve) you can take to help stop the other children from becoming infected with Giardia. How can I prevent a Giardia infection?Practice good hygiene.
Avoid water that might be contaminated.
In the United States, nationally distributed brands of bottled or canned carbonated water and soft drinks are safe to drink in terms of Giardia contamination. Commercially packaged non-carbonated soft drinks and fruit juices that do not require refrigeration until after they are opened (those that are stored unrefrigerated on grocery shelves) also are safe. For information on choosing safe bottled water, see CDC’s Fact Sheet A Guide to Commercially-Bottled Water and Other Beverages. If you are unable to avoid using or drinking water that might be contaminated, then you can make the water safer to drink by doing one of the following:
Avoid food that might be contaminated.
Avoid fecal exposure during sexual activity. This is especially important while experienccing diarrhea caused by giardiasis.
If my water comes from a well, should I have my well water tested?It depends. You should consider having your well water tested if you can answer “yes” to any of the following questions:
Tests used to specifically identify Giardia are expensive, difficult, and usually require hundreds of gallons of water to be pumped through a filter. If you answered “yes” to the above questions, consider testing your well for fecal contamination by testing it for the presence of coliforms or E. coli instead of Giardia. Although tests for fecal coliforms or E. coli do not specifically tell you whether Giardia is present, these tests might show whether your well water has been contaminated by feces. For more information on other germs and chemicals that can contaminate well water, see Contaminants in Well Water. These tests are only useful if your well is not routinely disinfected with chlorine, since chlorine kills fecal coliforms and E. coli. If the tests are positive, it is possible that the water may also be contaminated with Giardia or other harmful parasites, bacteria and viruses. Contact your local health department or your county cooperative extension service to find out who offers water testing in your area. For information on well testing, see Well Water Testing Frequently Asked Questions. If the fecal coliform test comes back positive, indicating that your well is fecally contaminated, stop drinking the well water and contact your local water authority for instructions on how to disinfect your well. This fact sheet is for information only and is not meant to be used for self-diagnosis or as a substitute for consultation with a health care provider. If you have any questions about the disease described above or think that you may have a parasitic infection, consult a health care provider. |
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Info CDC Home | CDC Search | CDC Health Topics A-Z This page last reviewed November 12, 2008 Centers for Disease Control and Prevention
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