Answer to Case 604

 Answer toParasite Case of the Week 604: Plant material, not a parasite. Although the large size and round shape in section superficially resembles a cross-section of a large roundworm (i.e.,Ascaris lumbricoides), there are some key features that allow us to identify this as plant material. As nicely stated by Florida Fan, " There does not seem to be a layer of polymyarian muscle cells as well as the other anatomical components such as a digestive tube or reproductive organs and no excretory organs either " which would be seen inAscaris lumbricoides.He also adds: " when magnified enough we can see polygonal cells often observed on vegetable matters. The other observation is that there is a fine brown line inside which I believe to contain melanin pigment, a character we do not find in helminths. "These are excellent observations on the key features for distinguishing plant material - in this, likely a cereal bran - from round worms. The polygonal cells are a characteristic feature of plants, and can be seen in the outer layer of the structure in this caseThis outer layer would likely have been birefringent with polarized light, which is another helpful feature for differentiating plant material from helminth body layers. Dr. Mary Parker, a botanist, kindly provided the following explanation for this case:  " I am pretty sure this is plant material, probably a few layers of the bran of a cereal grain. One of the layers of cereal bran contains a water-insoluble o...
Source: Creepy Dreadful Wonderful Parasites - Category: Parasitology Source Type: blogs