Answer to Case 667

 Answer to the Parasite Case of the Week 667: Ascaris lumbricoides. 

This adult nematode is easy to identify when found in human stool, or expelled through the mouth, nose, or anus, due to its large size and characteristic 3 fleshy lips. Importantly, anisakid larvae also have 3 fleshy lips, and must therefore be differentiated from immature Ascaris when expelled from the human gastrointestinal tract. This can be accomplished by examining the characteristics of the intestinal tract, mouth and tail.

Thanks again to Heather for this beautiful photograph!