Giardia lamblia

Abbreviation: Gl
Size cyst: 8 - 13 microns
Size trophozoite: 10 - 20 microns
Inhabits the small intestine of man and some animals.
Infection with Giardia lamblia is due to the ingestion of infective cysts in water or food.
Giardiasis incubation period is 12 - 15 days
The acute symptoms generally start with a general malaise followed soon by explosive diarrhea.
Chronic infection is possible with recurrent symptoms.
Trophozoites of G. lamblia in the small intestine encyst as they move down the intestinal tract. This is probably due to the change in pH and moisture content.
The trophozoites are tear drop shaped with 4 pairs of flagella and 2 nuclei. Usually identified in the special stain but may be seen in the concentrate wet mount.
The cyst, oval to round in shape, depending on the angle of view, contains 4 nuclei and a number of internal structures resembling fibrils(axonemes and median bodies).
If it were not for these internal structures differentiation between Endolimax nana and Giardia lamblia would be difficult.
At times the cytoplasm in a cyst appears to shrink away from the cell wall.
Giardia lamblia is a reportable organism.

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