6-month-old, male, domestic ferret (Mustela putorius furo)This 6-month-old, male domestic ferret presented to the referring veterinarian with a 1-2 week history of diarrhea and lethargy. On physical exam, the animal was assessed as being moderately dehydrated. The abdomen was moderately distended. Abdominal ultrasound showed marked enlargement of the spleen, multifocal areas of hyperechogenicity in the liver, and markedly enlarged mesenteric lymph nodes. Over the next week, diarrhea continued and the ferret became anorexic, lost weight, and developed a mild cough despite symptomatic treatment. Euthanasia was elected and the animal was submitted to the Diagnostic Center for Population and Animal Health, Lansing, MI for necropsy.

Gross Description:  

On gross necropsy, the animal was in fair to poor body condition with no visible fat stores and increased prominence of bony protuberances. Dehydration was marked as evinced by retraction of the eyes into the orbits and tackiness of visceral surfaces. The abdomen was prominently distended due to marked enlargement of the spleen and mesenteric lymph nodes. The spleen was approximately 10 times normal size, dark black and diffusely meaty. There were 7-8 relatively indistinct, poorly circumscribed, pale white, semi-firm, nodular foci dispersed throughout the splenic parenchyma. These foci ranged from 0.5-1.5 cm in maximum diameter, and the capsular surface of the spleen overlying few of these areas was slightly raised. The liver was diffusely mottled dark red and tan, and was mildly enlarged with slightly rounded borders. There were 10-12 slightly raised, occasionally coalescing, pale white, firm, slightly nodular plaques ranging from 0.5-1 cm in diameter randomly distributed on the capsular surface of the liver. The mesenteric lymph nodes were markedly enlarged being approximately 5-8 times normal size. The capsular surfaces of lymph nodes were irregular due to dozens of 2-5 mm in diameter, slightly raised white nodules. On cut surface, the normal nodal architecture was obliterated by pale tan to white, firm tissue (Fig. 3-1). The mesentery was irregularly thickened by dozens of coalescing pale white, firm nodules and irregular plaques. Similar white nodules and plaques were segmentally distributed across the serosal surfaces of the jejunum, ileum and to a lesser degree colon. In few areas, sections of intestinal loops were adhered to each other and to adjacent mesenteric lymph nodes by both fibrinous and fibrous adhesions. The visceral pleural surfaces of the lung were focally raised 1-3 mm by similar irregularly shaped, pale white, poorly demarcated, firm plaques that ranged from .2-1.5 cm in diameter. No other significant lesions were noted grossly.

Histopathologic Description:

In the wall of the small intestine, there are multifocal to coalescing areas of granulomatous to pyogranulomatous inflammation. These areas are most prominent on the serosal surfaces of the intestine, but also extend into the underlying tunic muscularis and more rarely into the submucosa and mucosa. Granulomas and pyogranulomas are characterized by variable central necrosis and infiltrates of degenerate neutrophils surrounded by thick dense bands of plump epithelioid macrophages and rare multinucleated foreign body type giant cells. Varying rings of lymphocytes, plasma cells, and dense maturing fibrosis surround granulomas. Granulomatous inflammation is generally randomly distributed, but occasionally is associated with vasculature. In sections of lymph node, nodal architecture is expanded and ablated by multifocal and coalescing granulomas and pyogranulomas similar to those described in the small intestine (Fig. 3-2). Granulomatous inflammation extensively extends through the capsule into the surrounding perinodal adipose tissue. Similar foci of granulomatous to occasionally pyogranulomatous inflammation expand the serosal surfaces of the liver and lung, and focally obliterate the normal parenchyma of the lung and spleen. In rare areas, the meninges overlying the cerebral cortex are expanded by granulomatous inflammation. Vasculature within tissue surrounding foci of granulomatous inflammation in the liver, lung, and cerebral cortex is segmentally surrounded by moderate cuffs of lymphocytes, plasma cells, and fewer histiocytes (Fig. 3-3). Immunohistochemistry using a generic antibody against Group 1 coronaviruses on sections of small intestine, lymph node, lung, and spleen demonstrated strong positive, intracytoplasmic immunoreactivity within macrophages at the center of granulomas. A generic coronavirus RT-PCR yielded amplification of a 650 base pair fragment. Sequencing of this segment suggests that the amplified virus is distinct from feline coronavirus (FeCoV). The amplified virus appears to be most closely related to ferret enteric coronavirus (FECV) that reportedly causes epizootic catarrhal enteritis (ECE) in ferrets.

Morphologic Diagnosis:  

Small intestine: Severe chronic segmental granulomatous to pyogranulomatous enteritis and peritonitis Lymph node: Severe chronic multifocal and coalescing granulomatous to pyogranulomatous lymphadenitis

Lab Results:  

PCR for Aleutian mink disease virus was negative.


Coronavirus-associated granulomatous disease

Contributor Comment:  

This case presentation represents a disease that has been termed granulomatous inflammatory syndrome (GIS) or ferret systemic coronavirus infection (FSCV).1,4 This is an emerging disease in ferrets that was first reported in the veterinary literature in 2006 and closely resembles the clinical, gross and microscopic features of feline infectious peritonitis.1,2,4

The exact etiopathogenesis of this lesion is unclear at this point, but appears to be related to infection with a group 1 coronavirus. Immunohistochemistry using monoclonal antibodies against feline coronavirus (FCoV) has been reported to demonstrate immunoreactivity in macrophages within lesions.1,2 This antibody is not specific for FCoV as it has been shown to detect other group 1 coronaviruses including ferret enteric coronavirus (FECV) that has been implicated as the cause of epizootic catarrhal enteritis (ECE).5,6 Electron microscopy confirmed the presence of coronavirus-like particles within macrophages.1 RTPCR using primers that detect a broad array of group 1 coronaviruses yielded amplification of a 599bp sequence that showed significant similarity to FECV (77% homology) and to other group 1 coronaviruses.1 Whether this virus represents a novel virus or variation within an already described coronavirus is unclear. The exact mechanism by which this virus causes the described lesions is unknown. Further characterization of the virus is required.

JPC Diagnosis:  

Small intestine: Enteritis and peritonitis, pyogranulomatous, multifocal to coalescing, moderate
Lymph node: Lymphadenitis, pyogranulomatous, multifocal to coalescing, moderate

Conference Comment:  

Coronaviruses are singlestranded RNA viruses of major importance in domestic animals.3 Coronaviruses are currently split into 3 serogroups. Group 1 includes transmissible gastroenteritis of swine (TGEV), canine coronavirus (CCV), feline coronavirus (FCoV), and human coronavirus 229E. Mouse hepatitis virus, sialodacryoadenitis of rats, turkey coronavirus (bluecomb), and bovine coronavirus are the major viruses recognized in group 2.1,3 Group 3 comprises the avian viruses and includes infectious bronchitis virus.1,3 As the contributor mentioned, ferret systemic coronavirus infection (FSCV) has an almost identical gross and histologic appearance as FIP in domestic cats. Juvenile and young adult ferrets seem to be the most susceptible to this disease.(1) Gross lesions consist of widespread nodular foci on multiple serosal surfaces that closely resemble similar foci seen in clinical cases of FIP.1 Involvement of mesenteric lymph nodes is also reminiscent of FIP in cats. FSCV closely resembles the dry form of FIP.1 Histologic lesions are identical to what is seen in cats with FIP and consist of pyogranulomatous inflammation with vasculitis and perivasculitis.1 Relevant clinical pathologic findings in these ferrets included a mild non-regenerative anemia (anemia of chronic disease), thrombocytopenia and hyperproteinemia.1 The thrombocytopenia was attributed to DIC secondary to vasculitis, while the hyperproteinemia occurred due to hyperglobulinemia.1


1. Garner MM, Ramsell K, Morera N, Juan-Sall+�-�s C, Jim+�-�nez J, Ardiaca M, Montesinos A, Teifke JP, L+�-�hr CV, Evermann JF, Baszler TV, Nordhausen RW, Wise AG, Maes RK, Kiupel M. Clinicopathologic features of a systemic coronavirus-associated disease resembling feline infectious peritonitis in the domestic ferret (Mustela putorius). Vet Pathol 45(2):236-46, 2008
2. Mart+�-�nez J, Ramis AJ, Reinacher M, Perpi+�-�+�-�n D. Detection of feline infectious peritonitis virus-like antigen in ferrets. Vet Rec 158:523, 2006
3. Murphy FA, Gibbs EPJ, Horzinek MC, Studdert MJ: Coronaviridae. In: Veterinary Virology, 3rd ed., pp. 495- 508. Academic Press, San Diego, California, 1999
4. Perpi+�-�+�-�n D, L³pez C. Clinical aspects of systemic granulomatous inflammatory syndrome in ferrets (Mustela putorius furo). Vet Rec 162(6):180-185, 2008
5. Williams B, Kiupel M, West K, Raymond JT, Grant CK, Glickmann LT, Coronavirus associated enzootic catarrhal enteritis (ECE) in ferrets (Mustela putorius furo): a review of 120 cases (1993-1998) JAVMA 217: 526-530, 2000
6. Wise AG, Kiupel M, Maes RK. A novel coronavirus associated with epizootic catarrhal enteritis (ECE) in ferrets. Virol 349:164-174, 2006

Click the slide to view.

3-1. Mesenteric lymph node

3-2. Mesenteric lymph node

3-3. Small intestine

Back | VP Home | Contact Us |