Mycobacterium genavense infection in two aged ferrets with conjunctival lesions

Mycobacterium genavense infection was diagnosed in two adult ferrets. Disseminated mycobacteriosis was diagnosed in a castrated 5-year-old sable ferret with generalised peripheral lymph node enlargement and a proliferative lesion of the conjunctiva of the nictitating membrane. The diagnosis was based on characteristic cytology and sequence analysis of the 16S rRNA gene amplified using the polymerase chain reaction from fresh biopsy material. Therapy with rifampicin, clofazimine and clarithromycin probably cured the infection. An entire 4-year-old female ferret with conjunctival swelling, serous ocular discharge and swelling of the subcutaneous tissues of the nasal bridge was diagnosed as having M genavense infection on the basis of typical cytology, histopathology and sequence analysis of 16S rRNA amplicons from formalin-fixed paraffin-embedded tissue. This patient was treated successfully using rifampicin. Both ferrets subsequently died as a result of other disease conditions, 10 and 4 months following initiation of therapy, respectively. This is the first report documenting M genavense as a cause of disseminated mycobacterial disease in ferrets. Conjunctival involvement may be a feature of disseminated mycobacteriosis in the ferret. The possibility that these infections were the consequence of a ferret retrovirus infection should be considered further.     

Hypofractionated radiation therapy for treatment of an adrenal mass in a ferret

Background: Ferret hyperadrenocorticism is the most common endocrine disease among domesticated ferrets. Current therapies include adrenalectomy and gonadotropin-releasing hormone analogs. Radiation therapy was used as an alternative noninvasive local therapy option. Case presentation: A 5-year-old male castrated ferret originally presented for pollakiuria. An abdominal ultrasound evaluation revealed an enlarged right adrenal gland with heterogenous parenchyma. Hypofractionated radiation therapy for treatment of the right adrenal mass was planned and performed using a small animal irradiator system. The prescribed radiation protocol was 30 Gray administered in 5 weekly fractions. The volume of the irradiated adrenal mass was serially quantified via the weekly cone beam CT. The adrenal mass volume decreased by 88% over the 10-month period. The ferret was euthanized 10 months postradiation therapy due to progressive co-morbidities, and the body was submitted for necropsy examination. No evidence of adrenal tissue or neoplastic tissue was found on histopathology of the irradiated right adrenal mass at the time of death. Evidence of systemic mycobacteriosis was discovered on necropsy. Conclusion and case relevance: Based on histopathologic evaluation, a complete response was achieved with hypofractionated radiation therapy of the right adrenal mass. Additional studies are needed to evaluate the safety and efficacy of this novel therapeutic approach.     

Adenosquamous Carcinoma of the Trachea in a Domestic Ferret (Mustela putorius furo)

A 4-year-old, castrated, male domestic ferret (Mustela putorius furo) was evaluated for a possible upper respiratory tract infection and wheezing for approximately 3 weeks. Supportive care for a suspected upper respiratory tract infection was initiated; however, the patient became progressively more dyspneic over the next 48 hours. A possible tracheal mass was identified upon thoracic radiographic imaging of the ferret. Tracheoscopy and a computed tomography scan of the neck and thorax confirmed the presence of a tracheal mass approximately 3 cm from the larynx obstructing 80% of the tracheal lumen. Rather than pursuing surgical resection, the owners elected humane euthanasia. An adenosquamous carcinoma of the trachea was diagnosed after histologic analysis. This tumor type has been diagnosed in the lungs of ferrets that were experimentally exposed to carcinogens found in cigarette smoke; however, there are no previous reports of this or any other tumor type associated with the ferret trachea. A tracheal mass causing a partial upper airway obstruction should be considered within the differential disease diagnosis list when a ferret is presented with dyspnea.     

Two cases of paraprostatic cysts in castrated male dogs

Two castrated male dogs presented for evaluation of tenesmus. Presurgical evaluations included complete physical examinations, serum biochemistry, abdominal ultrasonography, and MRI (case 2 only). Paraprostatic cysts were diagnosed in both cases based on the results of abdominal ultrasonography, MRI, and histopathology of tissue samples obtained during exploratory laparotomy. To the authors' knowledge, the two cases presented herein are the first documented cases of paraprostatic cysts that developed after castration in male dogs. Paraprostatic cysts should be considered in the differential diagnoses for castrated male dogs with prostatic disease.     

IMAGING FINDINGS IN 14 DOMESTIC FERRETS (MUSTELA PUTORIUS FURO) WITH LYMPHOMA

Lymphoma is the most common malignant neoplasia in domestic ferrets, Mustela putorius furo. However, imaging findings in ferrets with lymphoma have primarily been described in single case reports. The purpose of this retrospective study was to describe imaging findings in a group of ferrets with confirmed lymphoma. Medical records were searched between 2002 and 2012. A total of 14 ferrets were included. Radiographs (n = 12), ultrasound (n = 14), computed tomography (CT; n = 1), and magnetic resonance imaging (MRI; n = 1) images were available for review. Median age at the time of diagnosis was 5.2 years (range 3.25–7.6 years). Clinical signs were predominantly nonspecific (8/14). The time between the first imaging study and lymphoma diagnosis was 1 day or less in most ferrets (12). Imaging lesions were predominantly detected in the abdomen, and most frequently included intra‐abdominal lymphadenopathy (12/14), splenomegaly (8/14), and peritoneal effusion (11/14). Lymphadenopathy and mass lesions were typically hypoechoic on ultrasound. Mild peritoneal effusion was the only detected abnormality in two ferrets. Mild pleural effusion was the most common thoracic abnormality (3/12). Expansile lytic lesions were present in the vertebrae of two ferrets with T3‐L3 myelopathy and the femur in a ferret with lameness. Hyperattenuating, enhancing masses with secondary spinal cord compression were associated with vertebral lysis in CT images of one ferret. The MRI study in one ferret with myelopathy was inconclusive. Findings indicated that imaging characteristics of lymphoma in ferrets are similar to those previously reported in dogs, cats, and humans.     

Phimosis and paraphimosis in two ferrets (Mustela putorius furo)

Cases of paraphimosis are rarely described in ferrets. Phimosis has not been reported in the ferret. Two castrated ferrets with abnormalities of the prepuce were presented separately. Case 1 had a 4-month duration of a non-reducible paraphimosis. A shortening of the sheath prevented complete covering of the penis. Case 2 had dermatitis around the prepuce of a month's duration. The foreskin was distended by urine which could be eliminated through a barely visible opening by the application of manual pressure. The penis could not be extruded under general anesthesia. Surgery was performed in both cases. In case 1, parts of the skin of the prepuce, and mucosa of the sheath were resected to create an enlarged opening correcting the constriction of the penis. In case 2, a circular incision was made along the periphery of the skin with dermatitis, and the skin of the prepuce. The skin was resected to enlarge the preputial orifice. Surgical treatment was successful in both cases, did not present any technical difficulties, and was of a short duration. Surgical treatment of paraphimosis and phimosis have not been reported in ferrets and should be considered in cases of scalding of the prepuce not responding to medical treatments.     

Circumcaval ureter in two ferrets

BackgroundCircumcaval ureter is an anomaly in the development of the caudal vena cava, rarely reported in ferrets.Materials and methodsInclusion criteria for ferrets were circumcaval ureter confirmed on surgery or post-mortem examination. Data collection of ferrets with circumcaval ureters presented between January 2014 and January 2021 included signalment, medical history, clinical signs, laboratory diagnostics, diagnostic imaging results, treatments, and clinical outcomes.ResultsTwo ferrets met the inclusion criteria. One presented following diarrhea, and one was found on routine examination that revealed a right nephromegaly. Abdominal ultrasound revealed severe unilateral hydronephrosis associated with hydroureter in both ferrets. No obvious cause of obstruction was identified. Biochemical results were unremarkable in both patients. Hydronephrosis was investigated through CT scans, revealing Type 1 circumcaval ureter in both ferrets. Section and relocation of the right ureter by uretero-vesical anastomosis was performed in one ferret. This ferret died 48 hours later following a nephrectomy performed due to persistent hydronephrosis. The second cas underwent right nephrectomy andd ureter resection due to severe hydronephrosis and stenosis of the circuncaval segment. This ferret has remained healthy on followup with no abnormalities found in biochemistries or ultrasound examination.Conclusion and case relevanceFindings suggest that circumcaval ureter should be suspected in ferrets with unilateral hydronephrosis and associated hydroureter without any identified cause of obstruction on abdominal ultrasonography. It should be confirmed with CT scan and/or urography and treated surgically.     

Successful treatment of invasive nasal cryptococcosis in a ferret

Invasive cryptococcal rhinitis due to Cryptococcus neoformans var gattii was diagnosed in a castrated, 5-year-old, albino ferret with subcutaneous swelling of the nasal bridge. The diagnosis was based on histology, needle aspirate cytology and positive culture on Sabouraud's dextrose agar and birdseed agar. The ferret was successfully treated using a long course of itraconazole (25 to 33 mg orally once daily with food) subsequent to surgical debulking of the lesion, using sequential cryptococcal antigen titre determinations to guide therapy.     

Hepatic hemangiosarcoma in two ferrets (Mustela putorius furo).

Two ferrets were presented to the authors' clinic. Hemoperitoneum was diagnosed in one ferret, and an abdominal mass was palpated in the other. One ferret was euthanized and necropsied, and one ferret underwent exploratory laparotomy and liver lobectomy. In both cases, the histopathologic diagnosis was hepatic hemangiosarcoma.     

Acute ibuprofen toxicosis in a ferret

A 20-month-old 1.44-kg (3.2-lb) castrated male ferret was examined because of vomiting, defecating in an abnormal location, dyspnea, and signs of depression. Within 5 minutes of initial evaluation, the ferret became nonresponsive to all stimuli except deep pain. Despite intensive supportive treatment, the ferret died. Toxicologic analyses for ibuprofen were performed on serum, urine, and liver, using gas chromatography and mass spectrophotometry. Serum ibuprofen concentrations were 245 micrograms/g before and 269 micrograms/g after death. Acute ibuprofen toxicosis may cause severe lethargy progressing to coma, apnea, and death in ferrets. Ibuprofen toxicosis should be considered in differential diagnoses for ferrets with signs of depression, with or without clinical signs of gastrointestinal tract dysfunction.     

Thoracic vertebral chordoma in a domestic ferret (Mustela putorius furo).

A castrated adult male 1.0-kg domestic ferret (Mustela putorius furo) was referred for evaluation of a mass of >5 mo duration that was associated with the thoracic spine. The ferret had motor dysfunction and no conscious proprioception or pain perception in either hind limb. Segmental reflexes were present. Survey radiography, myelography, and magnetic resonance imaging showed a mass involving the ninth and 10 thoracic vertebrae and compressing the spinal cord. Decompressive surgery was performed, but clinical signs persisted. A diagnosis of chordoma was made using histopathology and immunohistochemistry. This is the first reported case of a chordoma involving the thoracic vertebrae in a domestic ferret.     

Open reduction and internal fixation with a locking plate for the treatment of a femoral fracture in a ferret (Mustela putorius furo)

Long bone fractures in ferrets (Mustela putorius furo) are usually traumatic in etiology, and the femur is commonly affected [1]. A 4-year-old, castrated male ferret was examined for acute, non-weight-bearing lameness of the left pelvic limb after presumably falling from its elevated enclosure. Clinical and radiographic evaluation showed a complete, comminuted fracture of the proximal diaphyseal third of the left femur. Open reduction and internal fixation (ORIF) of the left femoral fracture was performed with cerclage wires and a 1.5 mm locking compression plate with associated locking screws. Anatomic reconstruction was achieved, and postoperative radiographs confirmed appropriate fracture fragment apposition, limb alignment, and implant placement. At 9 weeks postoperatively, the ferret was ambulatory with no evidence of lameness, and complete radiographic union was noted. This is the first published report of the use of a bone plate for femoral fracture stabilization in a ferret. Bone plates, including locking plates, could be considered for long bone fracture stabilization in ferrets as an alternative to other methods.     

Cryptococcus gattii chorioretinitis in a ferret

Bilateral exudative chorioretinitis was diagnosed in an 18‐month‐old male neutered ferret (Mustela putorius furo) with a generalized Cryptococcus gattii infection confirmed by PCR. The animal was referred to the Ophthalmology Service of the Autonomous University of Barcelona (VTH‐UAB) for acute onset blindness. Complete ophthalmic examination revealed absent menace response and dazzle reflex in both eyes (OU), as well as subretinal edema located in the tapetal fundus. At that time, the clinical ophthalmologic diagnosis was bilateral exudative chorioretinitis. Treatment with prednisone (0.5 mg/kg PO q24 h) was instituted in addition to the ongoing treatment with fluconazole (10 mg/kg PO q24 h). The following rechecks revealed secondary cataracts with subsequent lens subluxation and panretinal degeneration OU. Despite being blind and the poor prognosis of disseminate cryptococcosis, the patient remained active and in good body condition during 6 months after the initial diagnosis. At that time, the ferret showed ataxia, incontinence, and generalized pain. A magnetic resonance imaging study revealed a mass affecting the spine. The owners declined further investigations and the ferret was humanely euthanized. The postmortem histopathology confirmed the initial diagnosis of cryptococcosis and the presence of intraretinal Cryptococcus spp. To the authors’ knowledge, this is the first report of Cryptococcus spp. induced exudative chorioretinitis in a ferret.     

Diffuse leptomeningeal histiocytic sarcoma in the cerebrospinal fluid of 2 dogs

Two adult male castrated dogs were evaluated for progressive paraparesis and ataxia. Neurologic examination showed severe ataxia, delayed proprioceptive placement in the pelvic limbs, pain upon palpation of the lumbar spine as well as facial paresis in one dog, and decreased withdrawal reflex of the pelvic limbs in the other dog. Magnetic resonance imaging (MRI) in both dogs showed diffuse meningeal and intramedullary lesions. However, no evidence of a mass was found. Biopsies could not be performed safely due to the location of the lesions. Cerebrospinal fluid (CSF) examination revealed an inflammatory pleocytosis associated with increased protein concentration and numerous large atypical round cells, often multinucleated. Nuclear fragmentation, micronuclei, and rare atypical mitoses were observed. Immunocytochemistry revealed CD1⁺ and CD11c⁺ staining, which, in concert with the morphology confirmed the diagnosis of histiocytic sarcoma (HS). Euthanasia was elected due to poor prognosis. Histopathologic examination showed diffuse spinal and meningeal infiltration with CD18⁺ neoplastic cells, without any evidence of mass formation, which completed the diagnosis of diffuse leptomeningeal HS involving the brain and the spinal cord. Canine central nervous system (CNS) HS has been seldom reported in the literature, with only isolated cases identified on CSF cytology. The cases reported here are remarkable in describing a diffuse CNS leptomeningeal HS associated with neoplastic cells in the CSF of dogs without a tumor mass. These cases emphasize the potential critical importance of CSF analysis in providing an antemortem diagnosis of neoplasia in neurologic patients.     

Diagnosis and treatment of a congenital portosystemic shunt in a ferret (Mustela putorius furo)

A 3-year-old female neutered ferret presented with progressive weight loss was diagnosed with portosystemic shunting based on increased fasting bile acids, rectal ammonia tolerance testing and advanced imaging. Ammonia reference values were determined in 16 healthy ferrets. A congenital extrahepatic spleno-caval shunt was visualised with ultrasonography and CT angiography of the abdomen. Complete surgical shunt closure by suture ligation was performed, without clinical improvement after surgery. Euthanasia was elected 4 months postoperatively because the clinical condition deteriorated. This is a case report of advanced diagnostics and surgical treatment of a congenital extrahepatic portosystemic shunt in a ferret, demonstrating rectal ammonia tolerance testing and imaging as feasible techniques for the diagnosis.     

Pyloric adenocarcinoma in a ferret.

Pyloric adenocarcinoma was diagnosed in a ferret with clinical signs of gastric distention. The development of this tumor may be related to Helicobacter mustelae infection in the gastric mucosa of ferrets. Pyloric adenocarcinoma has only recently been reported in ferrets and should be considered as a differential diagnosis for gastric distention in this species.     

Comparative vaginal cytology of the estrous cycle of black-footed ferrets (Mustela nigripes), Siberian polecats (M. eversmanni), and domestic ferrets (M. putorius furo).

Vaginal cytology and vulva size were used to characterize the reproductive cycle of female black-footed ferrets (Mustela nigripes), Siberian polecats (M. eversmanni), and domestic ferrets (M. putorius furo). Emphasis was on black-footed ferrets because of the need to breed these critically endangered animals and on Siberian polecats because of the close taxonomic relationship to black-footed ferrets. Vaginal cytology of the 3 species of ferret is similar. Proestrus was characterized by an increasing percentage of superficial epithelial cells and enlargement of the vulva. During estrus, superficial cells were usually greater than or equal to 90% of epithelial cells in the vaginal lavage and after several days were fully keratinized. Neutrophils were more common during all stages of the estrous cycle in domestic ferrets than they were in the other species. Following copulation, percentage of superficial calls in the vagina declined and vulva swelling subsided. Large cells, probably of uterine symplasma origin, were observed in vaginal lavages following whelping or pseudopregnancy. Vaginal cytology is extremely useful in the reproductive management of black-footed ferrets and Siberian polecats. Knowledge of normal vaginal cytology could be applied to the diagnosis of female reproductive abnormalities in all 3 species.