Species which are pathogenic to dogs include:
- Filaroides osleri (formerly Oslerus osleri)
- Filaroides hirthi
Adult F. osleri form nodules in the trachea and bronchi of dogs, where females deposit eggs that are transported via cilia and coughing into the oropharynx, where they are swallowed and pass out into the feces. The first stage larvae which develop in the soil of dog's habitat are directly infective and dogs reinfect themselves through ingestion of regurgitated stomach contents, or via feces from other dogs. Infection may also pass via oral transfer from bitches to pups during feeding. The prepatent period is 6 - 7 months.
These parasites commonly cause verminous tracheobronchitis, tracheal stenosis and pneumonia which can appear similar clinically to kennel cough. In younger dogs, acute onset dyspnea is common in heavy parasitism and complications with other diseases such as distemper are not uncommon.
Diagnosis is based on presenting clinical signs and evidence of eggs on coprological examination, which can be difficult as eggs are not always found. Fecal floatation using the Baermann technique and tracheal washes appear to be more successful at identifying this parasite.
Radiography of the chest often reveals a diffuse pulmonary infiltrate throughout the lungs. Haematological abnormalities usually reflect a neutrophilia and eosinophilia.
- Uni of Pennsylvania
- Bowman, DD (2009) Georgis' parasitology for veterinarians. Elsevier Saunders, Missouri. pp:190
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