VHOSPITAL.CLINIC · Parasite-Related Symptom
Diarrhoea is the hallmark symptom of giardiasis, affecting over 90% of symptomatic patients. The protozoan Giardia lamblia attaches to the duodenal mucosa, disrupting brush border enzymes and causing fat malabsorption — producing the characteristic greasy, foul-smelling stools.
Giardia trophozoites physically displace intestinal epithelial cells and release proteases that degrade tight junction proteins, increasing intestinal permeability and causing osmotic diarrhoea.
Related perspective
Diarrhea Caused by Giardiasis — Symptom-first view →Giardiasis affects the body in multiple ways. Beyond diarrhea, patients commonly experience:
Confirming Giardiasis as the cause of diarrhea:
Untreated giardiasis causes diarrhoea for 2–6 weeks. With metronidazole or tinidazole treatment, symptoms typically resolve within 5–7 days.
Not always. Giardia-related stool is typically greasy, pale, and foul-smelling due to fat malabsorption — not the watery diarrhoea typical of bacterial infections.
Yes. In untreated cases or in immunocompromised patients, giardiasis can cause chronic intermittent diarrhoea lasting months, leading to significant malnutrition.
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