The normal habitat of giardia is -

GIARDIA LAMBLIA: Habitat: Mucosa of duodenum and upper ileum of man. Morphology: 2 forms: Trophozoite and Cyst Infective stage: Cyst, Route of infection: Feco-oral route Cyst transforms to trophozoites which multiply in duodenum, attach to GIT mucosa by adhesive disk and later on, shed in the lumen, transforms to cysts which are passed in feces. They are the diagnostic form of the parasite. E.histolytica resides in distal ileum and caecum.