Canis ISSN: 2398-2942

Oslerus osleri infection

Synonym(s): Filaroides osleri, parasitic tracheobronchitis

Contributor(s): Lynelle Johnson

Introduction

  • Cause: infection with parasitic nematode.
  • Signs: chronic, non-productive cough.
  • Diagnosis: radiography, bronchoscopy, cytology.
  • Treatment: anthelmintic.
  • Prognosis: good, although severe infection may be difficult to resolve.
    Print off the owner factsheet Lungworms in dogs (Oslerus osleri) Lungworms in dogs (Oslerus osleri) to give to your client.

Pathogenesis

Etiology

Predisposing factors

General
  • Densely stocked kennels, eg Greyhound kennels.
  • Poor hygiene conditions.

Pathophysiology

  • Direct transmission is suggested.
  • Infection via feco-oral route, or regurgitated feeding → larvae pass via lymphatics to bronchial tree.
  • Worms develop in nodules → eggs layed by female are coughed up and swallowed to pass out in feces.
  • Infective larvae are ingested via contact with infected feces or contaminated environment.
  • Infection commonly acquired by puppies <6 weeks old through contact with infected dam.
  • Larvae penetrate intestine and migrate via lymphatics to lung.
  • Migrate from alveolar tissue into tracheobronchial tree and travel to bifurcation of trachea where they continue development in granulomatous nodules.
  • Nodules are completely encapsulated except for a small pore through which mature female lays eggs.
  • The eggs immediately hatch to release infective larvae which are coughed up and swallowed by host to appear in feces.
  • The nodules cause tracheobronchial irritation → chronic cough.

Timecourse

  • Months. (Although signs often appear around 5-6 months, many animals are not presented for investigation until months later.)

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Levitan D M, Matz M E, Finalen C S & Fister R D (1996) Treatment of oslerus osleri infestation in a dog - case report and literature review. JAAHA 32 (5), 435-438 PubMed.
  • Brownlie S E (1990) A retrospective study of diagnosis in 109 cases of lower respiratory disease. JSAP 31 (8), 371-376 VetMedResource.


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