Summary of Giardia lamblia
Giardia lamblia is a flagellated protozoan parasite that colonizes and reproduces in the small intestine, causing giardiasis. It occurs classically in campers and hikers who present with bloating, flatulence, and a foul-smelling, fatty diarrhea after drinking water contaminated with Giardia cysts. Metronidazole is the drug of choice for giardiasis. Gut IgA, secreted by plasma cells, protects against giardiasis (and other gut infections).