Microbiology & parasitology

Parasites-cutaneous / subcutaneous / soft tissue


Topic Completed: 15 April 2019

Minor changes: 5 October 2020

Copyright: 2019-2021, PathologyOutlines.com, Inc.

PubMed Search: Toxocara pathology skin

Nat Pernick, M.D.
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Cite this page: Pernick N. Toxocara. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/parasitologytoxocara.html. Accessed October 15th, 2021.
Clinical features
  • Member of ascarid family since adult worm has 3 lips
  • Cats are infected by Toxocara cati and Toxascaris leonina
  • Ingested eggs can hatch to release larva that cause larva migrans
  • Adult worms are not a risk to humans
  • T. leonina: little risk of clinical infection, although has been reported rarely in a human leg abscess and in children as visceral larval migrans
  • T. cati: higher risk than T. leonina of visceral larval migrans (visceral, ocular and neural) (Pritt: Creepy Dreadful Wonderful Parasites Blog - Answer to Case 538 [Accessed 15 April 2019])
Case reports
Gross description
Gross images

Contributed by Bobbi Pritt, M.D.

T. cati worms

Cytology images

Contributed by Bobbi Pritt, M.D.

T. cati egg

Pollen grain and Toxocara egg

Differential diagnosis
  • Pollen grain (Pritt: Creepy Dreadful Wonderful Parasites Blog - Answer to Case 529 [Accessed 20 September 2019]):
    • Superficially resembles ascarid eggs
    • Size and surface texture of eggs help to differentiate
      • Toxocara canis is 80 - 85 micrometers in greatest dimension with a golfball pitted surface texture
      • T. cati is 65 - 70 micrometers and also has the golfball pitting but smaller and less distinct than T. canis
      • Baylisascaris procyonis is 63 - 88 micrometers and has a granular surface texture
    • Pores also help to differentiate the pollen grain from a true helminth egg
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