Answer to Case 744

 Answer to theParasite Case of the Week 744:Mansonella perstansmicrofilariae.As described by Florida Fan, " This is a rather small microfilaria, its width is only about half the diameter of the surrounding neutrophils. The Carrazi stain [a hematoxylin-based stain] did not show a sheath either. As such, we can definitely rule out all the sheathed and large microfilaria. We know that we are dealing withMansonellaspecies. The tail of thisMansonellais not curved , this allows us to eliminateMansonella streptocerca(strepto = curved, cerca = tail) [and also the source is not tissue]. The tail is also not pointed, this rules outMansonella ozzardi. We only have one left with a blunt tail:Mansonella perstanswhich persists. " This image nicely shows all of these features:You have all done a great job learning to differentiate the small, unsheathed blood microfilariae (i.e.Mansonella perstansandM. ozzardi) from the larger, sheathed microfilariae. Of course, co-infections can occur, and the following is astunningphotograph ofM. perstansandLoa loaco-infection. I think we can all appreciated that theLoa loamicrofilaria is the top based on its larger size and sheath. Thank you for these outstanding cases, Idzi!Next week we will finish up with the tissue microfilariae. Will you be able to tell them apart?
Source: Creepy Dreadful Wonderful Parasites - Category: Parasitology Source Type: blogs