Parasitology Diagnostic Laboratory

Taenia sp.

The image below is of Taenia sp. This is the diagnostic egg of the intestinal cestode Taenia sp. typically found in human stools. These tapeworm eggs are yellow-brown, round to oval and measure 35-40 µm. They have a thick, radially-striated shell and contain an oncosphere embryo with 3 pairs of visible hooks. Infection occurs when raw or poorly cooked beef (or pork) containing encysted larvae is ingested. In the stomach, these larvae are released from the meat by digestion, and then attach to the wall of the small intestine. The adult worms mature in about 5-12 weeks and begin to produce proglottids containing infective eggs. Eggs are excreted in the stool and then onto the soil where the cycle continues.