Giardia trophozoites in endoscopic study and biopsy of the duodenum is seen in:

Biopsy of the small intestinal mucosa: Diffuse and specific lesions are seen in: 1. Whipple's disease Presence of periodic acid-Schiff (PAS)-positive macrophages in the lamina propria 2. Abetalipoproteinemia Normal mucosal appearance except for the presence of mucosal cells contain lipid postprandially and disappear following a prolonged period of fasting. 3. Immune globulin deficiency: Absence of plasma cells in the lamina propria; the mucosal architecture may be either perfectly normal or flat (i.e., villous atrophy). Patients are often infected with Giardia lamblia,Giardia trophozoites seen in the biopsy Ref: Harrison, E-18, P-2468.