Pearsonema spp

From Dog
Pearsonema spp egg showing the characteristic flattened bipolar plugs[1]
Larval immature stage of C. plica isolated from an 8-month-old symptomatic cat[2]

Pearsonema spp are a parasitic trichurid intestinal nematode which infect dogs, cats[3][4], foxes and wolves.

The normal definitive host for this parasite is thought to be badgers or foxes[5]. These worms weave the anterior portions of their bodies into the mucous membranes of the urinary bladder and other parts of the urinary tract. The eggs contain one cell which is passed into the urine.

The first stage-larvae develops within annelid worms (paratenic host), which is then eaten by the dog. Transmigration of infective larvae from the intestine into the viscera results in aberrant infections throughout the dog, but patent infections are the result of adult worms migrating into the urinary system, similar to what s observed with the giant kidney worm Dioctophyme renale[6].

Species which are pathogenic to dogs include:

  • Pearsonema plica (= Capillaria plica)

A related capillaria, Eucoleus aerophilus, infects the lungs of dogs.

Dogs are usually unaffected by even moderate infestations of this worm apart from rhinitis, but abdominal pain, fever, distended painful bladder and urinary blockage have been reported in other species.

Diagnosis is based on finding larvae and fragments of adult stages in urine sediment[2].

This parasite is readily treated with proprietary medicines such as fenbendazole and ivermectin.

Fenbendazole is given at 25 mg/kg twice daily for 10 days.


  1. Study Droid
  2. 2.0 2.1 Rossi M et al (2011) Symptomatic Capillaria plica infection in a young European cat. J Feline Med Surg Aug 9
  3. Bowman, DD et al (2003) Feline clinical parasitology. Iowa University Press, Iowa
  4. Castro O et al (2009) Two new records of helminth parasites of domestic cat from Uruguay: Alaria alata (Goeze, 1782) (Digenea, Diplostomidae) and Lagochilascaris major Leiper, 1910 (Nematoda, Ascarididae). Vet Parasitol 160(3-4):344-347
  5. Shimalov VV & Shimalov VT (2003) Helminth fauna of the red fox (Vulpes vulpes Linnaeus, 1758) in southern Belarus. Parasitol Res 89(1):77-78
  6. Bowman, DD (2009) Georgis' parasitology for veterinarians. 9th edn. Elsevier Saunders, Missouri. pp:226