Parasitology Training Manual
- 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.
Click on the image below to enlarge.
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