|PARASITES - Protozoa |
Giardia lamblia trophs
Giardia lamblia is the protozoan that causes giardiasis, with its accompanying severe diarrhea, abdominal discomfort, malabsorption, and/or weight loss. Outbreaks occur often in the United States due to consumption of impure water containing Giardia cysts. The cysts are somewhat resistant to chlorine. Boiling of water and/or filtration are normally required to kill them. Because Giardia may be acquired by drinking water in the wilderness without purification, its common name is "backpacker's parasite". |
Giardia moves with flagella, placing it in the class Mastigophora .Trophozoites (trophs) of Giardia lamblia are shown at 1000 X magnification in fecal material. Each troph is a bilaterally symmetrical pear-shaped flagellate usually possessing two nuclei, each with a central karysome that resembles "eyes on a face". An axostyle , appearing like a dark line through the center of the cyst, may be visible. Parabasal bodies may also appear as comma-shaped structures. Diagnosis depends on finding cysts or trophs in the stool.
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