Answer to Case 537

Answer toCase of the Week 537:EchinococcusspeciesShown here are the classic protoscoleces ofEchinococcus,each with a rostellum containing a row of hooklets (i.e. an ' armed ' rostellum). The rostellum is the anterior protrusion found on some tapeworms.As Old One mentioned, " There are 4 species ofEchinococcusthat infect humans:E. granulosus, E. multilocularis, E. vogeli, and E. oligarthus. Without more information such as host location, medical imaging, measurement of rostellar hooklets, one cannot be certain of the species. However one can make an educated guess.E. multiloculariscysts are [usually] sterile (no protoscoleces) [in humans],E. oligarthus is exceedingly rare in humans,E. vogeliphotoscoleces contain very few calcareous corpuscles, leavingE. granulosusas the best guess. "  I will also add that infections withE. oligarthusor E. vogeliare extremely uncommon in humans and occur in Central and South America.E. granulosusis, by far, the most common species causing human infection in the United States, and causes a form of disease called cystic echinococcus. Usually a single cyst is produced, within which multiple daughter cysts may develop. In comparison,E. multiloculariscauses alveolar echinococcus which infiltrates normal host tissue without remaining confined to a single cyst.I did not provide enough clinical or epidemiologic information to provide a species level ID. However, in this case, we also believe thatE. granulosuswas the most likely identification...
Source: Creepy Dreadful Wonderful Parasites - Category: Parasitology Source Type: blogs