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 µg/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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