"jee-ar-DYE-uh-sus") is an infection of the intestines caused by the parasite
The illness, also called
giardia (say "jee-AR-dee-uh"), is most often a problem in undeveloped countries where tap water is
become infected with giardia if you eat food or drink water that is tainted
with human or animal waste. In the United States and Canada, you can get
giardia by drinking untreated water from wells, streams, rivers, and lakes.
This is true even in mountain lakes and streams where the water may seem very
You can get giardia from someone else through:
Giardia can cause diarrhea,
stomach cramps, gas, and nausea. You may feel sick once and then get better. Or
your symptoms may come and go for some time. Some children with giardiasis do
not grow or gain weight normally. Sometimes giardiasis does not cause any
After a person is exposed to the parasite, it usually
takes 7 to 10 days for the infection to develop, but it can take from 3 to 25
days or longer. You can pass the infection to others during the entire time you
are infected. You may be infected for months, even if you don't have
Your doctor will ask questions about your past health and will do a physical exam to find out if you have giardiasis. He or she may also test your stool for the parasite that causes the infection.
Your doctor may prescribe
medicine to kill the parasite. Treatment also lowers the chance that you will
pass giardia to others. Taking all the medicine is important so the infection
does not come back.
In some situations, you may be tested for giardiasis even though
you don't have any symptoms. For example, this could happen during an outbreak
at a day care center. If tests show that you are infected, doctors recommend that
you get treatment even if you don't have symptoms. This is because a small
number of people who are not treated get a long-term infection.
If you have diarrhea, try eating small amounts of bland food until you
feel better. This gives your bowel a rest. But you need to take frequent sips
of clear fluids like rehydration drinks to avoid dehydration. This is
especially important for children, because they can become dehydrated
Some people with giardiasis have temporary trouble digesting milk and milk products. This is called lactase deficiency. If you have this problem, avoid these foods for at least 1 month. Then slowly add them back into your daily meals as your body can handle them.
There are some things
you can do to avoid giardiasis.
Learning about giardiasis:
The CDC Healthy Swimming website provides tips and fact sheets to help people reduce the chances of getting an illness from swimming in recreational waters such as lakes, rivers, swimming pools, and oceans. CDC's Healthy Swimming program also provides resources to raise awareness about recreational water illnesses (RWIs) and how to prevent them by practicing "Healthy Swimming" behaviors.
U.S. Centers for Disease Control and Prevention (CDC)'s website on parasites offers information on diseases caused by parasites. It provides information on topics such as malaria, neglected tropical diseases, and parasitic infections in the United States. There are also links to related information, such as a glossary and a site on healthy water, and other references and resources, such as statistics on parasitic diseases.
The CDC's Travelers' Health Web site provides health
information for the traveler. The Web site provides information on
immunizations that are needed for travel to various areas of the world. It also
provides information for safe travel, including traveling with children and
with people who have special needs. Information about current outbreaks of
disease in the world is also provided. The CDC is the leading federal agency
for protecting U.S. citizens' health and safety by providing credible health
information and health promotion.
This website is sponsored by the Nemours Foundation. It
has a wide range of information about children's health—from allergies and
diseases to normal growth and development (birth to adolescence). This website
offers separate areas for kids, teens, and parents, each providing
age-appropriate information that the child or parent can understand. You can
sign up to get weekly emails about your area of interest.
Other Works Consulted
Adachi JA, et al. (2012). Infectious diarrhea from wilderness and foreign travel. In PS Auerbach, ed., Wilderness Medicine, 6th ed., pp. 1360–1374. Philadelphia: Mosby.
American Academy of Pediatrics (2012). Giardia intestinalis (formerly giardia lamblia and giardia duodenalis) infections. In LK Pickering et al., eds., Red Book: 2012 Report of the Committee on Infectious Diseases, 29th ed., pp. 333–335. Elk Grove Village, IL: American Academy of Pediatrics.
Huston CD (2010). Intestinal protozoa. In M Feldman et
al., eds., Sleisenger and Fordtran's Gastrointestinal and Liver Disease, 9th ed., vol. 2,
pp. 1905–1919. Philadelphia: Saunders.
Yoder JS, et al. (2010). Giardiasis surveillance—United States, 2006–2008. MMWR, 59(SS-6): 15–25.
September 9, 2011
E. Gregory Thompson, MD - Internal Medicine
& W. David Colby IV, MSc, MD, FRCPC - Infectious Disease
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