Introduction

• Distress associated with difficult or labored breathing which leads to a shortness of breath.
• Cause: respiratory causes including disease of the upper and/or lower respiratory tract; non-respiratory causes include pain, anxiety, fever, heat stroke, obesity, abdominal distension, cardiac disease, metabolic disorders, neuromuscular disease, and anemia.
• Signs: depends on underlying cause. General: anorexia, lethargy, weight loss, poor hair coat. Increased respiratory effort, pyrexia, nasal discharge, sneezing, coughing, wheezing.
• Diagnosis: a complete physical examination with history. CBC/chemistries, microbiology, ELISA and IFA, PCR tests, nasal swab/wash, transtracheal wash or bronchoalveolar lavage, cytology of any exudate, ultrasound-guided lung aspiration, thoracentesis, abdominocentesis, histopathology, radiography, CT or MRI, ultrasonography, respiratory endoscopy.
• Treatment: oxygen administration, fluid therapy, anxiolytics, analgesia.
• Prognosis: poor if the ferret is open-mouth breathing; poor to grave for underlying disease such as neoplasia, cardiac disease; guarded to poor if a severely dyspneic ferret has not improved within 12 hours of intensive care.

Pathogenesis

Etiology

Respiratory causes

• Upper respiratory tract:
  • Nasal passage obstruction.
  • Rhinitis, sinusitis.
  • Dental disease Periodontal disease: tooth root abscess Dental abscess.
  • Trauma (to face, nose, neck).
  • Foreign body (ferrets are very inquisitive).
  • Neoplasia (such as nasal adenocarcinoma, lymphoma Lymphoma overview).
  • Laryngotracheal obstruction (edema, swelling from trauma): traumatic intubation, multiple intubation attempts, or inadvertent laryngeal trauma that occurred during dental procedures.
  • Canine distemper virus Canine distemper.
  • Influenza Influenza.
  • Contact irritation.
• Lower respiratory tract:
  • Pneumonia.
  • Bacterial (uncommon) Bacterial pneumonia:
    • Streptococcus pneumoniae, S. zooepidemicus, Groups C and G Streptococci.
    • Bordetella bronchiseptica.
    • Listeria monocytogenes.
    • Mycobacterium spp.
  • Viral (common):
    • Influenza Influenza.
    • Canine distemper Canine distemper.
    • Coronavirus Ferret systemic coronavirus.
  • Foreign bodies/material (aspiration):
    • Common.
    • Can be sequalae to force feeding, administration of oral medication, or incorrectly placed feeding tube.
  • Fungal:
    • Blastomyces dermatitidis.
    • Coccidioides immitis.
    • Histoplasma capsulatum.
    • Cryptococcus neoformans.
• Aspiration pneumonia may follow force feeding or oral medication.
• Neoplasia: lymphoma Lymphoma overview, pulmonary adenoma.
• Pulmonary edema (usually cardiogenic).
• Pulmonary contusion from trauma.
• Allergy (not well documented).
• Intrathoracic tracheal disease including neoplasia, abscess, foreign body.
• Extraluminal tracheal compression due to abscess or neoplasia.
• Traumatic airway rupture.

Non-respiratory causes

• Any cause of anxiety, pain.
• Obesity Obesity.
• Heat stroke Heat stress.
• Abdominal distension: pregnancy, organomegaly, dilation of stomach, ascites.
• Cardiac disease, including congestive heart failure, shock, severe arrhythmias Heart disease.
• Metabolic acidosis or uremia.
• Severe central nervous system disease such as trauma Trauma overview, abscess, neoplasia, inflammation.
• Spinal disease (trauma) Traumatic injuries.
• Anemia Anemia overview, common in hyperestrogenism in unmated in estrus jills.
• Iatrogenic: following multiple attempts at intubation or recent intubation.
• Diaphragmatic hernia.

Predisposing factors

General

• Poor husbandry which contributes to irritation of the airways, including:
  • Use of substrates that contain aromatic oils (such as pine, cedar).
  • Disinfectants/cleaning chemicals.
  • Poor sanitation that leads to ammonia build-up within the cage.
  • Smoke.
  • Inadequate/improper ventilation.
  • Ambient temperature.
  • Humidity.

Specific

• Immunosuppression due to poor diet, stress, age, overcrowding, concurrent disease, corticosteroid use.
• Laryngeal edema or trauma due to traumatic intubation, multiple intubation attempts, or inadvertent laryngeal trauma that occurred during dental procedures.
• Unvaccinated for canine distemper vaccine (no licensed ferret vaccine available in the UK).
• Contact with humans or other ferrets with respiratory signs.
• Contact with dogs or foxes transmitting canine distemper.
• Entire jills in season not being mated or not being brought out of season.

Pathophysiology

• Primary respiratory disease: upper or lower respiratory tract disease or dysfunction.
• Non-respiratory disease:
  • Abnormalities in pulmonary vascular tone as seen with central nervous system disease or shock.
  • Abnormalities with pulmonary circulation as seen with congestive heart failure.
  • Problem with oxygenation as seen with anemia.
  • Problems with ventilation: obesity, ascites, abdominal organomegaly, or musculoskeletal disease.
• Aspiration pneumonia: caudal portion of the left cranial lung lobe and the right middle lobe are most often affected.

Timecourse

• Depends on underlying disease.
• If dyspnea becomes severe such that there is open-mouth breathing; that is an acute development.

Epidemiology

• With infectious disease, there may be transmission between ferrets in a colony or household, including humans for viral infections.

Diagnosis

Treatment

Prevention

Outcomes