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Toxocara canis

Toxocara canis

Toxocara canis


  • Kingdom Animalia
  • Phylum Nematoda
  • Class Secernentea
  • Order Ascaridida
  • Superfamily Ascaridoidea
  • Family Ascarididae
  • Genus Toxocara

Final host

  • Dog, fox, wild canids


  • Adults: large (≈ 10 - 18 cm long, according to sex) white- cream-coloured worms
  • The mouth is surrounded by three large lips and the cuticle is expanded anteriorly forming a pair or large cervical alae
  • The tail of the male has a terminal narrow appendage, caudal papillae and two spicules
  • Female genital organs extend anteriorly and posteriorly to the vulva
  • Eggs are medium sized (≈ 90 x 75 µm), dark brown and subglobular with a thick rough pitted shell and granular unsegmented dark contents that normally fill the whole inner volume


  • Direct with ascaroid migration (larvae travel by blood-stream via liver, lungs and trachea to small intestine)
  • Transplacental and transmammary transmission in pregnant bitch
  • Ingestion of paratenic hosts induces direct intestinal route without migration


  • Small intestine


  • Intestinal content


  • Eggs


  • L3 within the egg
  • L3 within a paratenic host
  • L3 transplacental or transmammary route