Answer to Case 623

 Answer toParasite Case of the Week 623:Wuchereria bancroftimicrofilariaeThis case showed all of the classic features ofW. bancroftimicrofilariae, including the sheath which was nicely highlighted by the Delafield ' s hematoxylin stain. The sheath may not always be seen with routine Giemsa stain; when it is present, it often appears as a negatively-staining outline only. The Delafield ' s hematoxylin isn ' t routinely performed in the parasitology laboratory, but it is in all of the classic parasitology texts as an option for highlighting microfilariae sheaths. It ' s a beautiful stain!Here are the features of interest:Presence of a sheathNuclei do not go all the way to the tip (tip isWithout nuclei inWuchereria)Width of the microfilaria is about the same or greater than the surrounding WBCs on thin blood films. This is in contrast toMansonellaspp. which are more slender than the WBC diameter on thin films (important when a sheath is not seen).
Source: Creepy Dreadful Wonderful Parasites - Category: Parasitology Source Type: blogs