Respiratory disease caused by parasites (Proceedings) - Veterinary Healthcare


Respiratory disease caused by parasites (Proceedings)


Eucoleus aerophilus (Capillaria aerophila)

Epidemiology: Trichuroidea parasite with bi-operculate eggs. Direct life cycle.

  • Eggs – easily confused with those from other Capillarids (Eucoleus boehmi of the nose, and Pearsonema plica in the urinary bladder) and whipworms of dogs (Trichuris vulpis).
  • Adult worms – embed in the mucosal lining of large airways expelling eggs into the respiratory passages. Eggs - coughed up the trachea, and swallowed to be passed in the feces.
  • Infection – occurs by ingesting L1 larvae (take about 40 days to mature in eggs).Infections - can last as long as a year. PPP = 3 to 5 weeks.

Clinical Signs: Fairly common infection in both cats and dogs.

  • Most infections are asymptomatic - rarely causes clinical signs.
  • When signs occur:- mild wheezing, chronic cough can occur. Very rarely produces weight loss. When complicated with bacterial pneumonia, can cause death.
  • Thoracic radiographs may show diffuse mild bronchoalveolar pattern but are not pathognomonic.
  • Diagnosis made by finding bi-operculate eggs in feces or tracheal wash fluids.

Treatment: Assymptomatic cases do not require treatment.
  • Fenbendazole (50 mg/kg, PO, q24h, 14 days). Treatment of choice in dogs.
  • Ivermectin (200 g/kg, PO, once). Efficacy is unknown but is effective against nasal capillariasis and indications are that it is effective against E. aerophilus as well.

Filaroides hirthi

Epidemiology: Metastrongyloid nematodes found in the lung parenchyma of dogs. Direct life cycle.

  • Infection of pups probably occurs during nursing. After ingestion, larvae migrate to lungs via hepatic-portal or mesenteric lymph system. Prepatent period is 5 weeks. Larvae appear in the feces.
  • Most cases reported in beagles in research colonies.

Clinical signs: Nonproductive cough + increased respiratory rate.

  • Severe infestations: respiratory distress and exercise intolerance, looks like "kennel cough."
  • Radiographs: diffuse interstitial lung opacities and mixed alveolar patterns with consolidation

Treatment: Albendazole (25 mg/kg, PO, q12h, 5 days, then repeat treatment 2 wks later).

  • Fenbendazole (50 mg/kg, PO, q12h, 14 days), or Ivermectin (0.2 mg/kg, PO, q24h, 3 days).
  • Prednisone (1.25 mg/kg, PO, q24h, 14 days)

Paragonimus kiettiella

Epidemiology: Trematode (fluke) normally found in mink, but occasionally in the lungs of dogs and cats.

  • Adult pairs live in subpleural cysts that communicate with bronchiole. Eggs produced in the cysts are carried into the bronchiole, swept up airways and swallowed.
  • Carnivores infected by eating 2nd intermediate host (crayfish).

Clinical signs: Most are asymptomatic but those with disease present with a chronic cough (unresponsive to most treatments) and rarely pneumothorax.

Diagnosis: Identifying eggs (large, operculated) in feces or tracheal wash. Radiology; multiloculated cysts (dogs), and interstitial nodules (cats).

Treatment: Praziquantel (23 mg/kg PO, q8h, 3 days), or fenbendazole (50 mg/kg PO, q24h, 10-14 days).


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