Mycobacterium genavense Infection in a Domestic Ferret (Mustela putorius furo)

Mycobacterium genavense infection was diagnosed in an adult ferret with ptosis of the left eye, a proliferative lesion of the conjunctiva of the nictitating membrane, conjunctival swelling, and tumefaction of the periorbital tissues with a watery ocular discharge and the presence of a retrobulbar mass. The diagnosis was based on characteristic cytology of the retrobulbar mass and left mandibular lymph node that revealed granulomatous inflammation. Ziehl-Neelsen staining showed the presence of positive acid-fast bacilli in the cytoplasm of the macrophages. The diagnosis was confirmed by sequence analysis of the 16S rRNA gene amplified by using a multiplex polymerase chain reaction from a fresh lymph node biopsy. Therapy with marbofloxacin, rifampicin, and clarithromycin was recommended for 6 months and after this period, the veterinarian who was treating the ferret reported the disappearance of clinical signs. Six months after the end of the antibiotic treatment, the symptoms described previously reoccurred. Confirmatory laboratory tests were not performed but a recurrence of M genavense infection was suspected and the veterinarian, in agreement with the owner, euthanized the ferret.     

Extramural Ectopic Ureter in a Domestic Ferret (Mustela putorius furo)

Ectopic ureter is the most common cause of congenital urinary incontinence in the dog and cat. The occurrence of ectopic ureter in the dog has been estimated to be 0.016%. A 6-month-old ferret was evaluated for urinary incontinence and urine scalding around the perineal and inguinal areas. Ultrasonography showed a nondistended urinary bladder that contained a possible intraluminal blood clot. Excretory urography revealed a left ectopic ureter. The ferret was initially treated with oral amoxicillin-clavulanate and topical silver sulfadiazine ointment for the perineal and inguinal dermatitis associated with the incontinence. Because of the potential for complications and additional surgery with ureteral transplantation, a left nephroureterectomy was performed. Surgical recovery was uneventful and the incontinence improved, although a small amount of incontinence-associated dermatitis was still present 24 days after discharge. Phenylpropanolamine therapy was initiated to address a suspected dysfunction of the urethral sphincter. Urinary incontinence improved with the phenylpropanolamine therapy; however, a small amount of incontinence persisted throughout the 3 months in which the ferret was evaluated. To the authors' knowledge, this is the first report of an ectopic ureter in a domestic ferret.     

Congenital Peripheral Vestibular Syndrome in a Domestic Ferret (Mustela putorius furo)

A 3-month-old intact female ferret (Mustela putorius furo) was presented with a 2-month history of ataxia. On physical examination, the ferret had difficulty standing upright. During the neurologic examination, the patient had a left head tilt and positional strabismus, circled to the left, and was ataxic. Results of the complete blood count were consistent with a mild normocytic normochromic anemia. Initial treatment was supportive. Magnetic resonance imaging was performed and revealed an asymmetry of the inner ears. A brainstem auditory evoked response test was also performed. History, clinical signs, and diagnostic test results indicated that the ferret was suffering from congenital peripheral vestibular syndrome and left-sided deafness. Congenital disease should be considered in the differential diagnosis of young ferrets with peripheral vestibular syndrome. Supportive care and physiotherapy can improve balance and motor function, leading to an acceptable quality of life.     

Calvarial Osteoma with Cranial Vault Invasion in the Skull of a Ferret (Mustela putorius furo)

Osteoma is an uncommon tumor found in various animal species and is particularly rare or underreported in ferrets. A 2-year-old neutered male ferret (Mustela putorius furo) presented with an asymmetrical firm mass affecting the right dorsolateral skull. Radiographic images and computed tomography scans revealed a well-marginated mineralized mass involving the dorsal right calvarium that was growing concentrically into the cranium. A surgical biopsy sample was obtained and yielded a cytological diagnosis of sarcoma with reactive osteoblasts and osteoclasts and a histopathological diagnosis of osteoma. It was suspected that only the outer bony rim of the mass was submitted for histopathological evaluation, thereby adversely affecting the diagnostic quality of the sample. Based on interpretation of the combined imaging, cytological, and histopathological findings, a multilobular tumor of bone was suspected. Because of reduction in quality of life, the animal was euthanized 4 months after presentation, and postmortem examination yielded a definitive diagnosis of osteoma. This is the first report of an osteoma with cranial vault invasion in a ferret and is one of very few reports of this tumor diagnosed in this species. Lack of neurological signs in the patient, marked and extensive growth of the mass over several months, and the similar clinical appearance to other bony tumors leading to diagnostic ambiguity contributed to the distinctiveness of this case.     

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.     

Subcutaneous Liposarcoma in a Ferret (Mustela putorius furo)

A 6-year-old spayed female ferret (Mustela putorius furo) exhibiting clinical signs of weakness, anorexia, lethargy, weight loss, and frequent urination was presented for a veterinary evaluation to determine the underlying cause of the aforementioned abnormal behavior and clinical condition. Physical examination revealed a large, firm, painless, movable subcutaneous mass at the base of the tail. Radiographic and ultrasound images confirmed the presence of a soft tissue mass compressing the sacrococcygeal vertebrae, but there was no evidence of metastatic lesions. Because of the poor prognosis and progressive deterioration of the animal's clinical condition, the ferret was humanely euthanized. Gross necropsy revealed a 4 × 4 × 3.5 cm, firm, yellow-tan, ovoid, subcutaneous mass wrapped around the rectum and the anus. The mass did not appear to breach the serosa. Evaluation of the abdominal cavity revealed a pale yellow liver, possibly associated with hepatic lipidosis with no gross evidence of metastasis in the body cavity. The histopathological features of the mass were consistent with a liposarcoma. To the best of the authors' knowledge, this is the first case of subcutaneous liposarcoma reported in a ferret.     

Atrial Septal Defect in a Ferret (Mustela putorius furo)

A 2-year-old, male castrated ferret (Mustela putorius furo) was presented with progressive abdominal distention and loss of muscle mass despite normal appetite. Physical examination findings included pale mucous membranes, a prolonged capillary refill time, a pulse rate greater than 300 beats/min, and severe abdominal distention. Abdominal ultrasound showed free abdominal fluid and an enlarged liver with distended hepatic veins and caudal vena cava. During the echocardiographic examination, abnormalities observed included a 2-mm-diameter left-to-right shunting atrial septal defect (ASD) with concurrent severe dilatation of the right atrium and eccentric hypertrophy of the right ventricle with mild pulmonary hypertension. All other echocardiographic measurements were within normal limits. The owner declined treatment, and the ferret was euthanized. Postmortem examination confirmed the ultrasonographic findings. The free abdominal fluid (200 mL) was a non-septic fibropurulent exudate. Decompensated right-sided heart failure due to ASD and exudative peritonitis of undetermined origin were the final diagnoses. To our knowledge, this is the first report of an ASD in a ferret.     

Systemic Infection Due to Candida parapsilosis in a Domestic Ferret (Mustela putorius furo)

An 18-month-old castrated male ferret (Mustela putorius furo) was presented to the veterinary hospital for acute collapse but died despite initiation of emergency treatment. The body was submitted for a complete postmortem examination. The pathologist determined the ferret was suffering from severe necrotizing encephalitis, necrogranulomatous mediastinal lymphadenitis, and ulcerative dermatitis attributable to systemic Candida parapsilosis. This is the first report of systemic Candida parapsilosis in a ferret.     

Reproduction of the Female Ferret (Mustela putorius furo)

The domestic ferret is a seasonally polyoestrous species. Females reach puberty at the age of 8–12 months. Females exhibit a constant oestrus between late March and early August if they are not bred. Increasing tumescence in the pink-coloured vulva is a sign of pro-oestrus. Oestrus can persist for up to 5 months, but once ovulation is induced, either pregnancy or pseudopregnancy ensues. Follicular development and atresia overlap in such a manner that there is a recent cohort of follicles available for ovulation whenever copulation might occur. Copulation may last from 15 min to 3 h, the average being 1 h. Ovulation is induced by pressure on the cervix associated with copulation. After sufficient LH release, the pre-ovulatory follicles mature and an average of 12 oocytes (5–13) per female are ovulated 30–40 h after copulation into the ovarian bursa. The ferret oocytes are most capable of being fertilized up to 12 h after ovulation, i.e. 42–52 h after copulation. Ferret oocytes ovulate at the metaphase of the second meiotic division (MII) embedded in three layers of corona radiata cells. Embryos enter the uterus over a period of several days starting on day 5 after mating. Between days 12 and 13 after mating, the embryos have become implanted in the endometrium. Implantation in the ferret is central with rapid invasion of the uterine epithelium by the trophoblast over a broad area that eventually becomes a zonary band of endotheliochorial placenta. Gestation length is 41 days (39–42 days). The domestic ferret gives birth to an average of eight kits (1–18 kits), which weigh 6–12 g at birth.     

Testicular Neoplasms (Interstitial and Sertoli Cell Tumours) in a Domestic Ferret (Mustela putorius furo)

Unilateral testicular enlargement was detected in a 5‐years‐old domestic ferret during a routine sterilization. The right testicle showed two different types of proliferative lesions: (i) round nodules, well demarcated, showing a soft yellow tissue; (ii) white nodules, firm, with irregular‐shaped invaginations. Microscopically, the neoplastic proliferations were identified as an interstitial neoplasm and Sertoli cell tumour, respectively. The left testicle was small and showed intense testicular atrophy. Clinical evaluation of the ferret did not show any other apparent pathological processes. This study is the first case reporting the concomitant occurrence of a Sertoli cells tumour and an interstitial cell tumour in a domestic ferret.     

Surgical Repair of a Pelvic Fracture in a Ferret (Mustela putorius furo)

A 9-month-old, chemically spayed female ferret (Mustela putorius furo) presented after a fall (5.5 m) from the first floor of an apartment building. The animal was nonambulatory, with pain localized in the pelvic region. Radiographic examination revealed a bilateral fracture of the iliac body with medial displacement of the left hemipelvis and narrowing of the pelvic canal. Rib fractures, pulmonary contusions, and pleural effusion were also present on thoracic radiographic images. After emergency stabilization of the patient, the fracture of the left iliac body was successfully repaired using a composite internal fixation system with K-wires and polymethylmethacrylate. The implants allowed fracture healing despite loosening of one of the K-wires. Bony healing was achieved within 25 days, including the restoration of pelvic rigidity and maintenance of the diameter of the pelvic canal. Orthopedic examination was unremarkable 4 months following the surgical procedure. To the authors’ knowledge, this is the first described open reduction of a pelvic fracture in a ferret.     

Rhabdomyosarcoma in a ferret (Mustela putorius furo)

A 5-year-old spayed male ferret showed a subcutaneous mass in the right lateral thoracic wall. Microscopic examination revealed that the neoplasm had proliferated in the subcutis with infiltration into the surrounding tissues. A packed bundle of large polymorphic neoplastic cells, containing abundant eosinophilic cytoplasm and a round to ovoid, occasionally bizarre nucleus, were arranged interwoven. The neoplasm had metastasized to the right axillary lymph node. The neoplastic cells were intensively positive for vimentin, desmin and myoglobin. Skeletal muscle type creatine phosphokinase-positive granules were detected in the cytoplasm. Ultrastructurally, various amounts of disorganized myofibrils with focal density resembling the Z-band were shown in the cytoplasm of the neoplastic cells. The neoplasia was diagnosed as rhabdomyosarcoma.     

Distichiasis in a ferret (Mustela putorius furo)

A 4‐year‐old intact male ferret was presented to the Ophthalmology Service of the Department of Clinical Sciences of Companion Animals of Utrecht University with chronic blepharospasm, epiphora, and conjunctivitis of the right eye. Examination of the eye revealed mild conjunctivitis and three hairs protruding from the openings of meibomian glands in the upper eyelid, providing the clinical diagnosis of distichiasis. The distichia were removed by transconjunctival unipolar electrocautery. Recovery was uneventful, but the original signs recurred 10 weeks after surgery. Ophthalmic examination revealed another distichia at a different location in the same eyelid and it was removed by full‐thickness wedge excision. Histopathological examination failed to reveal the exact origin of the distichia. To our knowledge, this is the first reported case of distichiasis in a ferret.     

Cutaneous melanoma in a ferret (Mustela putorius furo)

A 4-year-old spayed female ferret (Mustela putorius furo) was clinically evaluated for a slightly raised subcutaneous mass in the dorsal lumbar area. The mass was surgically excised and submitted for histopathologic evaluation. Histologically, the mass was composed of closely packeted large, atypical, polygonal to spindle-shaped cells arranged in sheets and short bundles. A few cells contained variable amounts of granular, brown to black intracytoplasmic pigment. Warthin-Starry and Fontana-Masson silver stains demonstrated variable numbers of fine black intracytoplasmic granules in most cells. The atypical cells stained positively for vimentin and S100 protein and negatively for cytokeratin and Melan A. Ultrastructurally, the neoplastic cells contained intracytoplasmic melanosomes in different stages of development. Compound melanosomes were not identified. To our knowledge, this report documents the first case of a spontaneous cutaneous melanoma in the ferret.