Small intestine & ampulla

Infectious disorders


Last author update: 1 August 2012
Last staff update: 19 November 2020

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PubMed Search: Anisakis small bowel

Hanni Gulwani, M.B.B.S.
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Cite this page: Gulwani H. Anisakis. website. Accessed June 10th, 2023.
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

Gross images

Contributed by Bobbi Pritt, M.D.

Most likely a
type I Anisakis or

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

Contributed by Bobbi Pritt, M.D.

Most likely a type I Anisakis or Pseudoterranova: anterior boring tooth (left); mucron (terminal spicule-like structure) (right)

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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

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