Answer to Case 545

Answer: Not a human parasite: earthworm (Phylum Annelida, subclass Oligochaeta). It could very well be aLumbricusspecies as some readers suggested, but I don ' t know enough about the different genera of earthworms to tell you for sure. Perhaps a knowledgeable reader can educate us on this topic?So, wow, I ' ve been on a roll with these parasite mimics! I ' ll try my best to include some true parasites in upcoming posts. Those of you who have followed this blog for a while probably know that I am fond of mimics - probably because they are so commonly seen in the clinical microbiology lab and provide an interesting challenge to clinicians, patients and laboratorians alike. In this case, I ' m sure the patient wouldn ' t have hesitated to identify this object as an earthworm if it had been in a bait and tackle shop. It ' s when mimics end up in unfamilar settings (i.e., the toilet bowel) that they become a cause for alarm.So how did this earthworm end up in the toilet? My plumber friend tells me that this is not an uncommon occurrence since pipes break due to the wear and tear of being in the ground. Tree roots, it would seem, are the enemy of sewage pipes.For those of you wondering how to tell an earthworm apart from other large worms (e.g.,Ascaris lumbricoides), here are some of the defining features that are not seen in human parasites:1. Clitellum - the thickened glandular non-segmented portion of the earthworm ' s body found in sexually-mature adults.2. Segmented body...
Source: Creepy Dreadful Wonderful Parasites - Category: Parasitology Source Type: blogs