# DBT JRF 2022 — Question 57

Exam: DBT JRF 2022 · Section: B · Topic: Microbiology › Parasitology - Giardiasis · Difficulty: Medium

## Question

Which one of the following is the most accurate statement regarding giardiasis?

## Options

- **A.** The drug of choice for giardiasis is chloroquine.
- **B.** Giardia lamblia produces an enterotoxin that increases cAMP within the enterocyte, resulting in diarrhea.
- **C.** Giardia lamblia infection is acquired by ingestion of food or water contaminated with human feces only (i.e. there is no animal reservoir for this organism).
- **D.** Infection by Giardia lamblia occurs principally in the small intestine frequently resulting in the malabsorption of protein and fat.

## Answer

Option D

## Explanation

Giardia lamblia: site of infection and pathogenesis: Giardia lamblia (also G. intestinalis or G. duodenalis) is a flagellated protozoan parasite: • Site of infection: SMALL INTESTINE (duodenum and jejunum) • Attachment: Giardia trophozoites attach to intestinal epithelium via a ventral adhesive disc. • Pathogenesis: - Disrupts brush border microvilli → reduces absorptive surface area - Decreases disaccharidase activity (lactase, etc.) → osmotic diarrhea - Inhibits lipase activity → steatorrhea (fat malabsorption), bloating • Clinical features: Profuse watery diarrhea, flatulence, abdominal cramps, weight loss. • Transmission: Fecal-oral route via contaminated water or food (cysts are infectious). Contrast with E. histolytica (large intestine) and Cryptosporidium (small intestine but different pathogenesis). Answer: Giardia infects the small intestine, causing malabsorption of fats and proteins.

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