|Description:||Magnified 128X, this photomicrograph revealed the presence of a cestode, Diphyllobothrium latum, or “fish” or “broad” tapeworm, egg, which is described as oval or ellipsoidal, and ranges in size from 55µm to 75µm X 40µm to 50µm. There is an operculum at one end that can be inconspicuous, and at the opposite (abopercular) end is a small knob that can be barely discernible. The eggs are passed in the stool unembryonated.|
Diphyllobothriasis can be a long-lasting infection (decades). Most infections are asymptomatic. Manifestations may include abdominal discomfort, diarrhea, vomiting, and weight loss. Vitamin B12 deficiency with pernicious anemia may occur. Massive infections may result in intestinal obstruction. Migration of proglottids can cause cholecystitis or cholangitis.
Microscopic identification of eggs in the stool is the basis of specific diagnosis. Eggs are usually numerous and can be demonstrated without concentration techniques. Examination of proglottids passed in the stool is also of diagnostic value.