Encyclopedia of Parasitology

2016 Edition
| Editors: Heinz Mehlhorn

Oslerus Species

  • Heinz Mehlhorn
Reference work entry
DOI: https://doi.org/10.1007/978-3-662-43978-4_4120


Osler = name of a veterinarian scientist. Latin: rostratus = provided with a pointed end.

Geographic Distribution/Epidemiology

Worldwide among felids, canids, and in other carnivores, especially common in rearing facilities.

Morphology/Life Cycle

The species O. rostratus (in felids) and O. osleri (in canids) live in nodules within the mucous layer of the bronchia and of the trachea. The males reach a length of 6 mm, while the females may have the double size. The females deposit their larva 1 containing eggs in the breathing system of their hosts. The larva 1 reaches within the mucus the mouth of their hosts, from where they enter the esophagus or may be transmitted by licking other hosts (e.g., females transmit them to puppies).

Symptoms of Disease

The nodules in trachea and in the bronchioles reach diameters of about 1 cm and thus pose problems during breathing and introduce symptoms like coughing, which may reach a chronic phase.


Microscopical determination of the 350 μm long larvae 1, which can be isolated from the feces by help of the Baerman technique.


Oral uptake of larvae 1 from saliva or feces of infected cats, dogs, or their wild relatives.


Very difficult in free roaming animals (due to possible ingestion of vomited material or licking at infected animals).

Incubation Period

2–3 weeks.

Prepatent Period

5–6 weeks.


Long lasting to repeated self-infections.


Ivermectin (0.2–0.4 mg/kg bodyweight subcutaneously) and also moxidectin showed high efficacy, while fenbendazole and oxfendazol needed applications for several weeks in order to reduce the size of the nodules in the trachea.

Further Reading

  1. Chaoqun Y et al (2011) Filaroides osleri (Oslerus osleri): two case reports and a review of canid infections in North America. Vet Parasitol 179:123–129CrossRefGoogle Scholar
  2. Dunsmore JD, Spratt DM (1979) The life history of Filaroides osleri in wild and domestic canids in Australia. Vet Parasitol 5:275–289CrossRefGoogle Scholar
  3. Outerbridge CA, Taylor SM (1998) Oslerus osleri tracheobronchitis: treatment with ivermectin. Can Vet J 39:238–240PubMedPubMedCentralGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  1. 1.Institut für Zoomorphologie, Zellbiologie und ParasitologieHeinrich-Heine-UniversitätDüsseldorfGermany