Common diseases of ferrets (Proceedings)

Insulinoma

Very common in ferrets

Tumor of the beta cells in the pancreas that secrete excessive levels of insulin

Results in hypoglycemic episodes

      • Weakness

      • Lethargy

      • Salivation

      • Pawing at mouth

      • Seizures

      • Difficult to awaken from naps*

Generally malignant with metastasis to the liver, spleen, and other tissues

Presumptive diagnosis based on blood glucose level (<70mg/dl)

More than 1 test: non-fasted and then 4-6 hours fasted

Insulin levels can help to distinguish insulinoma from other causes of hypoglycemia

Definitive diagnosis based on histopathology of biopsy samples taken at exploratory laporatomy

Treatment

Surgical

      • Debulk extensive tumor

      • "shell-out" suspicious nodules

      • Pancreatic lobectomy

      • Post-op pancreatitis is rare

Medical

      • Dietary management

           o High protein

           o High fat

           o Frequent feedings

           o High sugar material on hand and to only be used in a hypoglycemic crisis

      • Chromium Picolinate may help in regulating glucose levels

           o Found in Brewer's yeast

           o 1/8 – 1/4 tsp per ferret 1-2 times per day

      • Prednisolone

           o Promotes gluconeogenesis by inhibiting glucose uptake by tissues

           o Raspberry flavored

           o Dose ranges: 0.1mg/kg – 4 mg/kg SID to BID

           o Start low then raise as needed to maintain adequate glucose levels

      • Diazoxide

           o Inhibits insulin release and reduces cellular uptake of glucose

           o Used alone or in conjunction with Prednisolone

           o Dose : 5-10 mg/kg BID

While insulinomas are rarely cured, most affected ferrets can be reasonably controlled and will often live months to years following diagnosis

Adrenal Endocrinopathy (Key Points)

      • Very common in ferrets

      • Represented by adrenal hyperplasia, adenomas, and adenocarcinomas

      • Usually >3 years of age

      • Left more commonly affected than right

      • Estrogen is most commonly secreted hormone NOT cortisol

      • Carcinomas slow to metastasize

      • Diagnosis not easy to confirm

           o Endocrinopathy can be useful if the correct tests are performed

           - Measure estrogen precursors NOT cortisol

           o Ultrasound has been useful but only 50% successful

           - Size greater than 3mm wide consistent with enlargement

Clinical Signs

      • Hair loss

      •       Pruritus

      • Enlargement of vulva in females

      • Loss of muscle mass/ weight loss

      • Skin can appear thin or almost translucent

      • Pot-bellied appearance

      • Aggressive or mating behavior

      • Urination difficulties in males

      • Enlargement of mammary tissue in either sex

      • Sometimes anemia &/or decreased platelets

           o Abdominal palpation – can palpate an enlarged adrenal in approx. 1/3 of cases

           o CBC, Chemistry panel, Radiographs, and Urinalysis can all be normal – but useful to look at concurrent disease

           o Sometimes will see estrogenic bone marrow suppression (anemia – normocytic/normochromic) (leukopenia) (thrombocytopenia)

           o Recommend adrenal endocrine panel from Univ. of Tennessee

           - Need 0.5cc of serum, frozen, by next day delivery

           - Measures cortisol, 17 OH Progesterone, Estradiol, Androstenadione, and DHEAS.

           - Cost = $60 + S/H

           o Treatment

                  ▪ SURGICAL REMOVAL! #1

                        • Left much easier to remove

                        • Right adrenal is close to the vena cava and can encompass this large abdominal vein

                        • If both removed have to think about steroid supplement

                        •* Surgical treatment of bilateral adrenal disease by subtotal bilateral adrenalectomy is effective with a low rate of complications and post-operative recurrence rate.

                        • Cryosurgery**- benefits include dec. bleeding, less intraoperative time, a quicker recovery & technically easier procedure

Medical

Lupron* (leuprolide acetate)– a long acting GnRH analog that stops the stimulation to the adrenal glands therefore decreasing the levels of both sex steroids & androgens

      • injectable drug available in 24 hr, 1 mo. depot, 3 mo. depot, and 4 mo. depot.

      • No clinical research done on the 24hr, 3mo. or 4 mo. Depot

      • *Only research available on the 1 month depot

     Dose: * 100mcg/kg IM of the 1 mo. depot diluted

      • comes in 3.75mg formulation: dilute to concentration of 500mcg/ml

      • can be stored indefinitely at –70C serum freezer or a liquid nitrogen storage.

      • possible using regular freezer but drug stability unknown – suspected to be 6 mo.

      • 1 vial costs $400 & will treat approx. 35 ferrets

Melatonin* – a natural hormone secreted by the pineal gland.

      • melatonin is involved in "activating" (in the spring) & "terminating" (in the fall) the ferret's hypothalmic-pituitary-gonadal axis in response to the seasonal changes in the photoperiod.

      • Melatonin inhibits GnRH release, decreases LH and FSH, and ultimately decreases the sex hormone concentrations.

      • Dose: 1mg/kg given 8-9 hours after sunrise or 0.5mg PO q 24 hrs

      • Implants

Estrogen Toxicity

           o Rarely encountered now due to early spaying

           o Jills are induced ovulators so remain in heat until bred

           o These extended periods of estrus lead to bone marrow suppression & pancytopenia

           o Weak, pale, and sometimes shocky, vulva can be swollen and turgid

           o Anemia, leukopenia, and thrombocytopenia present

           o Treatment: OVH

                ▪ Human chorionic gonadotropic (HCG) 100 IU once and repeated in 2 week can be given to stimulate ovulation

                ▪ Transfusion may be necessary

                ▪ All ferrets have the same blood type

                ▪ Use whole blood

Lymphosarcoma

           o Third most common neoplasia

           o Affects ferrets of any age

           o Lymphadenopathy is the hallmark of the disease

           o Peripheral lymphocytosis may be seen on CBC

           o Diagnose with histopathology or cytology

           o Treatment

                ▪ Vincristine

                ▪ Cyclophosphamide

                ▪ Prednisolone

                ▪ Doxorubicin

           o Prognosis is guarded although remissions of 3 months to 5 years are reported

Proliferative Bowel Disease

           o Same disease that swine and hamsters develop

           o Caused by the organism – Lawsonia intracellularis

           o Chronic diarrhea is the primary clinical sign

           o Partial rectal prolapse is sometimes seen

           o Weight loss due to malabsorption

           o Young ferrets most commonly affected

                ▪ 10-16 weeks of age

                ▪ Nutritional and environmental stressors play a role

           o Difficult to culture

           o PCR for swine available

           o Indirect FA to ID omega antigen in swine, hamsters and ferrets

           o Presumptive diagnosis based on signalment & clinical signs and even histopath lesions

           o Treatment: Chloramphenicol 50mg/kg BID

                ▪ Fluids and nutritional support also needed

Helicobacter Gastritis

           o Spiral shaped gram – rod bacteria

           o Causes gastritis and gastric ulceration

           o Clinical signs

                ▪ Vomiting

                ▪ Anorexia

                ▪ Weight loss

                ▪ Diarrhea

                ▪ Melena

           o Definitive diagnosis based on surgical or endoscopic examination of gastric lining

           o Treatment

                ▪ Amoxicillin 20mg/kg BID

                ▪ Metronidazole 20mg/kg BID

                ▪ Gastrointestinal protectants

                     • Bismuth subsalicylate 1cc/kg BID

                     • Cimetidine 10mg/kg TID

                     • Sucralfate 25mg/kg BID

                     • Omeprazole

                     • Ranitidine

Epizootic Catarrhal Enteritis

           o Unknown viral etiology (coronavirus)

           o Affects ferrets of any age but most will have a history of recent exposure to other ferrets

           o Often seen following shows, fairs, or in shelter ferrets

           o Clinical sign

                ▪ Green, mucoid diarrhea = "green slime disease"

                     • Voluminous and sometimes explosive

                ▪ Can progress to GI ulceration>melena>anemia

           o Diagnose based on history and clinical signsNecropsy Findings

           o Histopath shows lymphoplasmocytic enteritis with villar atrophy and blunting

           o Treatment = supportive care

           o High morbidity, low mortality

           o Most recover in a matter of 2-4 weeks

                ▪ More severe in older ferrets with concurrent disease

Influenza

           o Ferrets are susceptible to human influenza viruses

           o Mild to moderate upper resp. signs seen 48 hours post exposure

                ▪ Sneezing, nasal discharge, lethargy, anorexia

                ▪ Biphasic fever spike documented, but usually missed

                ▪ +/- enteritis

           o Disease is usually self limiting and treat symptomatically

                ▪ 5-14 days duration

                ▪ Diphenhydramine 0.5-2mg/kg BID

                ▪ Fluids and Nutritional support as necessary

      • Myofasciitis = Disseminated idiopathic myositis (DIM)

           o New emerging fatal disease

           o Noncontagious

           o Progressive and ultimately fatal

           o 1 WEEK – MONTHS

           o Young adult ferrets (6-18 months)

           o Clinical signs

                ▪ Acute onset of pain

                ▪ Reluctance to move

                ▪ Fever

                ▪ Leukocytosis with mature neutrophilia

                ▪ Failure to respond to antibiotics & anti-inflammatory meds

                ▪ Mild non-regenerative anemia

                ▪ Mild hypoalbuminemia

                ▪ Mild hyperglycemia

Necropsy Findings

      • Gross

      • Atrophy of leg & rib muscles with thin diaphragm

      • White streaks in muscle

      • White splotches in heart

      • Red/white mottling of esophagus*

      • Entire length

      • Check tongue

      • Reddened and inc. friability of adipose tissue

      • Reddened lungs

      • Splenomegaly

      • Reddened bone marrow

Histopath

      • Necrosis & loss or atrophy of myofibers

      • Suppurative to pyogranulomatous inflammation in muscles

      • Suppurative to pyogranulomatous inflammation in heart

      • Full length, circumferential, full thickness suppurative inflammation in all tunics but mucosa*

      • Suppurative inflammation in adipose tissue adjacent to muscle, lungs, mediastinum

      • Myeloid hyperplasia in spleen and bone marrow

Cause undetermined

      • Bacterial and viral cultures negative

      • PCR and immunohistochemistry negative

      • Immune mediated?

Treatment

      • Many drugs used – unsuccessful

      • Combo ?

      • Chloramphenicol, prednisone, cyclophosphamide