A stool sample from a young man with chronic diarrhoea and steatorrhoea shows pear-shaped trophozoites with two nuclei and four pairs of flagella. Which structural feature mediates attachment of this organism to the duodenal mucosa?
- A Undulating membrane
- B Ventral adhesive disc ✓
- C Cytostome with ciliary tufts
- D Axostyle
Correct answer: B. Ventral adhesive disc
Explanation
Giardia lamblia trophozoites attach to the small intestinal brush border through a rigid ventral sucking (adhesive) disc, producing malabsorption and steatorrhoea without mucosal invasion. An undulating membrane identifies trichomonads, which are urogenital parasites. B cytostome is a feature of Balantidium coli, and an axostyle is seen in Trichomonas, so both fail to fit the described organism.
Reference: Paniker's Textbook of Medical Parasitology, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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