Respiratory disease caused by parasites (Proceedings) - Veterinary Healthcare


Respiratory disease caused by parasites (Proceedings)


Trachea and bronchi

Crenosoma vulpis

Epidemiology: Metastrongyloid nematode of bronchi (dogs and other canids). Adult worms (males; 4 to 8 mm long, females; 12 to 16 mm long) parasitize the terminal bronchi of the respiratory tract where eggs are laid, develop and hatch, larvae then coughed up and swallowed to be passed in the feces.

  • Dogs infected when ingest gastropod (snails) intermediate hosts. Larvae migrate to the lungs by way of the visceral lymphatic or via the hepatic portal system: prepatent period about 18 to 21 days.

Clinical signs: Infection occurs during summer in dogs living or visiting rural areas frequented by foxes, the more usual definitive host. - dry, nonproductive cough easily elicited by tracheal palpation. Cough may be chronic and productive.
  • Radiology: Diffuse bronchial patterns with prominent interstitial markings.
  • Bronchoscopy: Moderate mucoid to mucopurulent discharge in the airways. Cytology of tracheal wash: reveal inflammatory cells, mainly eosinophils (matching a peripheral eosinophilia).

Diagnosis: Larvae (pointed tail, 250 - 300 um) in feces or tracheal wash sample.

Treatment: Fenbendazole (50 mg/kg PO, q24h, 3 days, or 20 mg/kg, PO, q24h, 14 days).

  • Levamisole (7.5 mg/kg, PO, once, followed by a second dose 2 days later).

Oslerus osleri

Epidemiology: Metastrongyloid nematode: causing nodules in the terminal trachea and bronchi of dogs and other canids (coyotes, foxes). Adult worms found in subepithelial fibrous nodules usually close to the bifurcation of the trachea and extending down into the mainstem bronchi. Thin-shelled eggs or larva (L1 - infective stage and very similar to F. hirthi) are coughed up, swallowed, enter feces, or coat regurgitated food.

  • Direct lifecycle. Pups infected by L1 in sputum (infected when cleaning, or coating regurgitated food.

Clinical signs: Dry cough (often precipitated by exercise or tracheal palpation) unresponsive to antibiotics or


  • Severe respiratory distress due to upper airway obstructive disease.

Diagnosis: L1 in fecal samples or in transtracheal washes. Bronchoscopy: identifies the brown reddy nodules at the tracheal bifurcation. Radiology may reveal soft tissue nodular densities at the tracheal bifurcation.

Treatment: Physical removal of nodules via bronchoscopy can be life saving.

  • Oxfendazole (10 mg/kg PO, q24h, 28 days). Only drug known to work.
  • Prednisone (0.5 - 1 mg/kg PO, q12h, 5 days post-nodule removal). Removes inflammation with worm death.


Glass EN, Cornetta AM, deLahunta A, et al. Clinical and clinicopathologic features in 11 cats with cuterebra larvae myiasis of the central nervous system. J Vet Intern Med 1998;12:365-368.

Gunnarsson LK, Moller LC, Einarsson AM, et al. Clinical efficacy of milbemycin oxime in the treatment of nasal mite infection in dogs. J Am Anim Hosp Assoc 1999;35:81-84.

Barr SC. Feline Lungworm (Aelurostrongylus). In: Canine and Feline Infectious Diseases and Parasitology. Barr SC and Bowman DD (eds). Ames Ia: Blackwell Publishing. 2006. p. 233.

Peterson EN, Barr SC, Gould WJ, et al. Use of fenbendazole for treatment of Crenosoma vulpis in a dog. J Am Vet Med Assoc 1993;202:1483-1484.

Kelly PJ, Mason RP. Successful treatment of Filaroides osleri infection with oxfendazole. Vet Rec 1985;116:445-446.

Barr SC, Lavelle RB, Harrigan KE, et al. Oslerus (Filaroides) osleri in a dog. Aust Vet J 1986;63:334-336.

Error Page - Veterinary Healthcare


Error Page
CG(n0) [org/apache/xerces/impl/XMLErrorReporter.reportError(Lorg/apache/xerces/xni/XMLLocator;Ljava/lang/String;Ljava/lang/Stri
Can't Find What You Seek?
DVM360 has been redesigned to present the great print and Web content from DVM Newmagazine, Veterinary Medicine, Veterinary Economics, and Firstline magazine by content area. Some pages may have moved. Please search at the top of this page or click on one of the links below to find what you are looking for.


Click here