Recognizing the dyspneic ferret
Ferrets (Mustela putorius furo) with respiratory disease exhibit clinical signs that are similar to those seen in dogs and cats, including non-specific signs of illness (Fig 1), such as reduced appetite, lethargy, and weight loss, sneezing, oculonasal discharges, as well as tachypnea, and labored breathing or dyspnea. When compared to other species like the dog, cough is relatively rare in the dyspneic ferret.
Key points of urgent care
Initial management of the dyspneic ferret should focus on stabilization, including supplemental oxygen. Oxygen can be delivered via face mask, with the diaphragm removed, or by placing the ferret in an oxygen cage. Pulse oximetry is an easy and non-invasive technique, however this equipment is not intended for use in ferrets and the accuracy of results is questionable. Nevertheless, changes or trends in oxygen saturation may provide valuable clinical information.
Although it is desirable to establish intravenous access as soon as possible in a dyspneic patient, this is not always possible or practical in the ferret. Use your own clinical judgment to determine if your patient will tolerate the necessary restraint.
Signalment and history
- How old is the ferret?
Some infections, such as distemper virus and feline infectious peritonitis (FIP)-like disease, are more commonly reported in young animals (Perpiñán et al 2008, Garner et al 2008)
- Is the vaccination status of the ferret current?
Ferrets are extremely susceptible to canine distemper virus.
- Obtain a detailed clinical history. Have the owner describe the onset and progression of clinical signs.
Some conditions, such as bacterial pneumonia, may be associated with acute episodes of labored breathing (Martínez et al 2011).
Ferrets that present severely dyspneic with open-mouth breathing and/or cyanosis should first be stabilized and provided with supplemental oxygen (see Key Points above). Carefully observe the patient’s breathing pattern and carefully auscultate the lung fields and heart. Perform a complete physical examination to look for clues to the underlying cause of respiratory difficulty. For instance, the ferret with canine distemper will display not only respiratory signs, but also dermatologic and gastrointestinal problems (Fox and Marini 2014, Perpiñán et al 2008) (Box 1).
|Mucopurulent oculonasal discharge
|Facial, chin, and perineal dermatitis
Crusting dermatitis of lips, eyes, nose, footpads, and perineum
|Neurologic signs||Muscle tremors, seizure activity, and coma are possible but rare
Clinical signs of feline infectious peritonitis (FIP)-like disease can include dyspnea, but more commonly ferrets suffer from diarrhea and central nervous system deficits (Garner et al 2008).
A variety of etiologies can be associated with respiratory difficulty in ferrets, ranging from degenerative disease and infection to neoplasia or trauma. Among the many potential causes of respiratory signs in the ferret, the most important differentials include:
- Respiratory tract disease caused by influenza virus or canine distemper virus (Martínez et al 2011, Perpiñán et al 2008)
- Primary heart disease such as congestive heart failure
- Heartworm disease
Influenza is a common, but fortunately relatively harmless, cause of respiratory signs in pet ferrets. Ferrets are susceptible to influenza type A and B. Although it is theoretically possible for ferrets to transmit influenza virus to people, transmission occurs primarily via aerosol droplets from ferret to ferret or from human to ferret (Barron and Rosenthal 2012, Maher and DeStefano 2004). As in their human counterparts, influenza infection commonly begins as rhinitis that progresses to tracheobronchitis. Clinical signs in afflicted ferrets include the rapid onset of sneezing, nasal discharge, lethargy, and fever. Infection can extend to interstitial pneumonitis but this is rare except in the very young or the immunocompromised patient. The course of clinically illness typically lasts 3 to 5 days in uncomplicated cases (Maher and DeStefano 2004).
Traumatic or structural injury, like hemothorax or diaphragmatic hernia, is another potential cause of respiratory distress in the pet ferret. Lymphoma, associated with pleural effusion and possibly a mediastinal mass, is also a possible cause for dyspnea in the ferret. A viral disease of growing importance is a systemic pyogranulomatous inflammation resembling FIP. Partial DNA sequencing indicates this virus is related to ferret enteric coronavirus (Garner et al 2008, Martina et al 2003). Ferrets are also susceptible to pneumonia and pleuritis caused by bacterial infection or fungal agents such as Blastomyces dermatitids, Coccidiodes immitis, Cryptococcus spp., and Histoplasma capsulatum (Darrow et al 2014, Fox and Marini 2014, Martínez et al 2012, Eshar et al 2010). The fungal agent Pneumocystis carinii has also caused pneumonia in immunosuppressed ferrets (Stokes et al 1987).
- Blood collection for hematology/biochemistry panel testing can be delayed until the patient is stable.
Anemia and hypergammaglobulinemia have been reported with distemper virus and FIP-like infection (Perpiñán et al 2008, Garner et al 2008). Thrombocytopenia has also been described in FIP-like infection (Garner et al 2008).
- Use survey radiographs to screen the heart and lung fields.
Look for cardiomegaly, consolidation or parenchymal masses, pleural effusion, or increased soft tissue density within the mediastinum.
- Perform thoracic ultrasound to more thoroughly evaluate the heart, mediastinum, and pleural space.
- Use fine needle aspiration to collect samples for cytologic evaluation of pleural effusion or intrathoracic mass lesions.
Treatment will vary with the underlying cause of dyspnea, but may include nebulization with saline, antimicrobials, and/or mucolytics; thoracocentesis of pleural effusion to allow lung re-expansion, and/or anti-inflammatory agents. For many conditions, drug regimens and drug dosages are extrapolated from what is used in cats. For instance, furosemide (1-4 mg/kg PO, SC, IM, IV q8-12h), nitroglycerin (1/16-1/8 in per animal q12-24h), and an anxiolytic such as midazolam (0.25-0.3 mg/kg SC, IM) may prove therapeutic in congestive heart failure (Morrisey 2013).
Prognosis varies with the underlying cause of disease, ranging from good in uncomplicated cases of influenza to grave for ferrets with distemper virus infection. In a recent case report, most animals with distemper died or were euthanized because of respiratory complications (Perpiñán et al 2008).
Barron HW, Rosenthal KL. Respiratory diseases. In: Quesenberry KE, Carpenter JW (eds). Ferrets, Rabbits, and Rodents: Clinical Medicine and Surgery, 3rd ed. Elsevier Saunders, St Louis, MO. 2012: 80.
Belser JA, Katz JM, Tumpey TM. The ferret as a model organism to study influenza A virus infection. Dis Model Mech 4(5):575-579, 2011.
Darrow BG, Mans C, Drees R, et al. Pulmonary blastomycosis in a domestic ferret (Mustela putorius furo). J Exotic Pet Med 23(2):158-164, 2014.
Eshar D, Mayer J, Parry NM, et al. Disseminated, histologically confirmed Cryptococcus spp. infection in a domestic ferret. J Am Vet Med Assoc 236(7):770-774, 2010.
Fox JG, Marini RP (eds). Biology and Diseases of the Ferret, 3rd ed. Ames, IA: John Wiley & Sons; 2014.
Garner MM, Ramsell K, Morera N, et al. Clinicopathologic features of a systemic coronavirus-associated disease resembling feline infectious peritonitis in the domestic ferret (Mustela putorius). Vet Pathol 45(2):236-246, 2008.
Maher JA, DeStafano J. The ferret: an animal model to study influenza virus. Lab Anim 33(9):50-53, 2004.
Martina BEE, Haagmans BL, Kuiken T, et al. SARS virus infection of cats and ferrets. Nature 425 (6961):915, 2003.
Martínez J, Martorell J, Abarca ML, et al. Pyogranulomatous pleuropneumonia and mediastinitis in ferrets (Mustela putorius furo) associated with Pseudomonas luteola infection. J Comp Pathol 146(1):4-10, 2012.
Menicagli F, Lanza A, Sbrocca F, et al. A case of advanced second-degree atrioventricular block in a ferret secondary to lymphoma. Open Vet J. 6(1): 68-70, 2016.
Morrisey JK. Ferrets. In: Carpenter JW, Marion CJ (eds). Exotic Animal Formulary, 4th ed. St. Louis, MO: Elsevier; 2013: 569-572.
Perpiñán D, Ramis A, Tomas A, et al. Outbreak of canine distemper in domestic ferrets (Mustela putorius furo). Vet Rec 163(8):246-250, 2008.
Stokes DC, Gigliotti F, Rehg JE, et al. Experimental pneumocystis carinii pneumonia in the ferret. Br J Exp Pathol 68(2):267-276, 1987.
Bezos J, Álvarez-Carrión B, Rodríguez-Bertos A, et al. Evidence of disseminated infection by Mycobacterium avium subspecies hominissuis in a pet ferret (Mustela putorius furo). Res Vet Sci 109:52-55, 2016.
Desmarchelier M, Lair S, Dunn M, Langlois I. Primary hyperaldosteronism in a domestic ferret with an adrenocortical adenoma. J Am Vet Med Assoc 233(8):1297-1301, 2008.
DuVal-Hudelson KA. Coccidiomycosis in three European ferrets. J Zoo Wildl Med 21(3):353-357, 1990.
Lenhard A. Blastomycosis in a ferret. J Am Vet Med Assoc 186(1):70-72, 1985.
Malik R, Martin P, McGill J, et al. Successful treatment of invasive nasal cryptococcosis in a ferret. Aust Vet J 78(3):158-159, 2000.
Williams J. What is your diagnosis? J Am Vet Med Assoc 217(11):1625-1626, 2000.
Wylie SE, Kelman M, Ward MP. Epidemiology and clinical presentation of canine distemper disease in dogs and ferrets in Australia, 2006-2014. Aust Vet J 94(7):15-22, 2016.
Pollock CG. Presenting problem: Dyspnea in ferrets. LafeberVet Web site. Available at https://lafeber.com/vet/presenting-problem-dyspnea-in-ferrets/