Felis ISSN 2398-2950

Capillaria aerophila

Synonym(s): Eucoleus aerophilia, C. aerophila, C. aerophilus

Contributor(s): Maggie Fisher, Grace Mulcahy, Stephen Barr, Eran Dvir




  • Class: Nematoda.
  • Superfamily: Trichuroidea.
  • Genus: Capillaria.
  • Capillaria aerophila is a trichuroid nematode affecting domestic and wild carnivores and, sometimes, humans. It may cause respiratory distress in cats. It is a new emerging pathogen with a worldwide distribution. Global warming is a potential driver to the spread of this parasite.

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Clinical Effects



  • Adults in trachea and bronchi of dog, fox, coyote, wolf and other wild mammals, and occasionally cats.
  • Eggs in environment.
  • Possibly there is an earthworm paratenic host.


  • The cat acquires the infection by ingestion of larvated eggs from the environment or possibly from earthworms as well.
  • The ova hatch in the intestine.
  • Larva migrate via the blood stream or the lymphatics into the lungs.
  • The adults reside and mate beneath the respiratory epithelium.
  • The female lay eggs that are coughed, swallowed and released via the feces.


  • Direct feco-oral transmission with fecal excretion of eggs and ingestion of infective eggs.
  • The earthworm might act as a paratenic host.

Pathological effects

  • No age immunity but disease more common in younger animals.
  • Adults embedded for their full length in the mucosa cause a catarrhal inflammation of the trachea and bronchi.
  • Inhalation of eggs and secondary bacterial infection may lead to bronchopneumonia.

Other Host Effects

  • General respiratory distress.
  • Bronchovesicular sounds.
  • Sneezing.
  • Wheezing.
  • Chronic cough.
  • Bronchopneumonia Pneumonia and respiratory failure in severe cases.


Control via animal

  • Anthelmintic treatment.
  • Remove from access to eggs in soil and/or fox environment.
  • Consider all in contact dogs and cats potentially infected.

Control via chemotherapies

  • No conclusive evidence for effective treatment.
  • Either Ivermectin Ivermectin (not licensed for use in cats). Efficacy has been reported for nasal and urinary capillariasis in a few dogs, so it may have benefit in tracheal infection.
    Or Fenbendazole Fenbendazole (20-50 mg/kg/day) (unlicensed for use in cats) 30 mg/kg for 2 days and repeated 4 times at 4 weekly intervals has reported efficacy in foxes and could be useful, although fenbendazole showed no efficacy for urinary capillariosis.
  • Relatively new spot-on preparations are showing good response for therapy of capillariosis including:
    • Emodepside.
    • Imidacloprid Imidacloprid 10%/moxidectin Moxidectin 1%.
    • Abamectin (0.3 mg/kg, subcutaneous, repeated in 2 weeks).

Control via environment

  • Eggs are susceptible to desiccation in sunlight.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Di Cesare A, Iorio R, Crisi P et al (2015) Treatment of Troglostrongylus brevior (Metastronyloidea, Crenosomatidae) in mixed lungworm infections using spot-on emodepside. J Feline Med Surg 17 (2), 181-185 PubMed.
  • Di Cesare A, Otranto D, Latrofa M S et al (2014) Genetic variability of Eucoleus aerophilus from domestic and wild hosts. Res Vet Sci 96 (3), 512-515 PubMed.
  • Traversa D & Di Cesare A (2013) Feline lungworms: what a dilemma. Trends in Parasitology 29 (9), 423-430 PubMed.
  • Traversa D, Di Cesare A, Di Giulio E et al (2012) Efficacy and safety of imidacloprid 10%/moxidectin 1% spot-on formulation in the treatment of feline infection by Capillaria aerophilia. Parasitol Res 111 (4), 1793-1798 PubMed
  • Conboy G (2009) Helminth Parasites of the Canine and Feline Respiratory Tract. Vet Clin North Am Small Anim 39 (6), 1109-1126 PubMed.