Histopathology / Microbiology · 25 May 2021 0

Some gastrointestinal pathogens and their differentiating features.

Gastrointestinal pathogens are very common in routine practice. It takes experience and keen observation to differentiate gastrointestinal pathogens from one another. In case of confusion, go with your ‘GUT’ feeling.

Lets look at a few differentiating features of Giardia lamblia, Cryptosporidium parvum and Isospora belli.

  1. GIARDIA LAMBLIA:

Pear shaped trophozoites with 2 ovoid nuclei, present in the luminal surface. They are 10-15 microns in length and 5-9 microns in width.

GIARDIA IS SEEN IN THE LUMINAL SURFACE

CRYPTOSPORIDIUM IS SEEN ATTACHED TO ENTEROCYTES LIKE SMALL BEADS.

2. CRYPTOSOPORIDIUM PARVUM

In tissue biopsies, 2 – 5 μm basophilic round bodies are seen protruding from the apex of enterocytes (“blue beads”) within the cell membrane. Parasites bulge out of apex of epithelial cells

ISOSPORA IS LARGEST AMONG THE THREE. IN CONTRAST TO GIARDIA AND CRYPTOSPORIDIUM – ISOSPORA DOES NOT HAVE AN APICAL LOCATION, INSTEAD LOCATED IN THE TIP OF VILLI.

3. ISOSPORA BELLI

Oocysts are generally ovoid to ellipsoid in shape, range from 10-40µm in length by 10-30µm in width. Cysts are present in PARASITO-
PHOROUS VACUOLE. Does not have an apical location.

Look below for a quick summary

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