Webster's New World Medical Dictionary

giant platelet syndrome
See 
Bernard-Soulier
syndrome.
Giardia lamblia
A parasite responsible for a
common form of infectious diarrhea. The parasite
lives in two stages: trophozoites and cysts.
Trophozoites are the active form of the parasite
inside the body. Cysts represent the resting stage that
enables the parasite to survive outside the body.
Infection begins from swallowing the Giardia cysts.
The acid in the stomach activates the cysts, which in
turn release the disease-causing trophozoites. The
parasites attach to the lining of the small intestine,
reproduce, and are swept down the intestine in the
fecal stream. Cysts form in the lower intestines and
are then passed in the feces. See also 
giardiasis.
giardiasis
A contagious form of diarrhea caused
by the parasite Giardia lamblia. Transmission is most
common by direct contact with infected feces or by
eating food or drinking water contaminated by feces.
Giardia is one of the most common intestinal para-
sites in the world, and the disease is most prevalent
in developing countries. Giardia is also a major
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giardiasis
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http://www.rashidislamiccenter.com
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cause of waterborne outbreaks of diarrhea in the US.
It particularly affects diapered children and toddlers
being toilet-trained. Symptoms include a sudden
explosive, watery, foul-smelling diarrhea; excessive
gas; abdominal pain; bloating; nausea; tiredness;
and loss of appetite. Fever is unusual. If not treated,
giardiasis can last for months or even years. The
diagnosis is made by microscopic identification of
the parasite in stool. Tests that detect antigens (pro-
teins) to Giardia in the feces are especially useful for
screening children in day-care settings, and for test-
ing adults after treatment. Treatment may be with
metronidazole (Flagyl). See also 
Giardia lamblia.