Small bowel (small intestine)
Infectious disorders

Author: Hanni Gulwani, M.D. (see Authors page)

Revised: 14 February 2018, last major update August 2012

Copyright: (c) 2003-2018,, Inc.

PubMed Search: Anisakis small bowel

Cite this page: Gulwani, H. Anisakis. website. Accessed October 18th, 2018.
Definition / general
  • Larvae of ascarids (Anisakidae) are found in sea animals
  • After ingesting contaminated raw fish or other sea food, larvae attach to mucosa of stomach or small intestine and cause ulceration, penetration or perforation
Diagrams / tables

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Life cycle

Case reports
Clinical images

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Larvae in terminal ileum

Larvae in fish

Larvae in a herring

Microscopic (histologic) description
  • Serositis, mucosal edema, submucosal abscess with eosinophils surrounding parasite with unpaired excretory gland (renette cell), Y shaped lateral epidermal cords, no apparent reproductive system and a ventriculus (glandular esophagus)
  • No lateral alae, no ventricular appendage, no intestinal cecum
Microscopic (histologic) images

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Larva in submucosa with eosinophils and lymphocytes

Larva in jejunum; note its intestinal lumen (L), the large lateral chords (LC) with a butterfly-like shape and many somatic muscle cells (MC); also a marked eosinophilic infiltrate with neutrophils and lymphocytes