Microbiology & infectious diseases
Parasites-gastrointestinal (not liver)
Ascaris
Author: Nat Pernick, M.D.
Last author update: 7 August 2019
Last staff update: 11 February 2022
Copyright: 2019-2025, PathologyOutlines.com, Inc.
PubMed Search: Ascaris[TI] pathology full text[sb]
Table of Contents
Case reports | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Videos | Differential diagnosisCite this page: Pernick N. Ascaris. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/parasitologyascaris.html. Accessed January 15th, 2025.
Case reports
- Objects were seen in a concentrated wet prep of a stool specimen from an international adoptee from Ethiopia (Pritt: Creepy Dreadful Wonderful Parasites Blog - Case of the Week 550 [Accessed 7 August 2019])
- Nematode in fresh (unfixed) stool specimen (Pritt: Creepy Dreadful Wonderful Parasites Blog - Case of the Week 553 [Accessed 9 August 2019])
Gross description
- Anterior end has characteristic 3 fleshy lips common to all ascarids (Pritt: Creepy Dreadful Wonderful Parasites Blog - Answer to Case 553 [Accessed 9 August 2019])
Gross images
Contributed by Bobbi Pritt, M.D.
Adult with 3 fleshy lips
Microscopic (histologic) description
- Ascaris lumbricoides can have both mammillated and decorticated eggs (Pritt: Creepy Dreadful Wonderful Parasites Blog - Answer to Case 550 [Accessed 7 August 2019])
- Mammillated: having relatively small protrusions from the exterior, most commonly the surface
- Decorticated: to remove the bark, rind or husk from, i.e. to remove the outer mammillated layer
Microscopic (histologic) images
Contributed by Bobbi Pritt, M.D. and Institute of Tropical Medicine Antwerp
Ascaris lumbricoides eggs, decorticated
Videos
Creepy Dreadful Wonderful Parasites Case
Differential diagnosis
- Other helminth eggs such as hookworm and Schistosoma japonicum (Pritt: Creepy Dreadful Wonderful Parasites Blog - Answer to Case 550 [Accessed 7 August 2019]):
- When only decorticated eggs are seen, they can be confused for other helminth eggs
- Size and thick shell can be used to reliably differentiate them
