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)

     o Very common in ferrets

     o Represented by adrenal hyperplasia, adenomas, and adenocarcinomas

     o Usually >3 years of age

     o Left more commonly affected than right

     o Estrogen is most commonly secreted hormone NOT cortisol

     o Carcinomas slow to metastasize

     o Diagnosis not easy to confirm

          ♦ Endocrinopathy can be useful if the correct tests are performed

               • Measure estrogen precursors NOT cortisol

          ♦ Ultrasound has been useful but only 50% successful

               • Size greater than 3mm wide consistent with enlargement

     o 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

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

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

                    o *Only research available on the 1 month depot

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

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

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

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

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

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

          o                    o ; "terminating" (in the fall) the ferret's hypothalmic-pituitary-gonadal axis in response to the seasonal changes in the photoperiod.

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

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

                    o 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 signs

     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

     o 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

     o Cause undetermined

          ♦ Bacterial and viral cultures negative

          ♦ PCR and immunohistochemistry negative

          ♦ Immune mediated?

o Treatment

          ♦ Many drugs used – unsuccessful

          ♦ Combo ?

          ♦ Chloramphenicol, prednisone, cyclophosphamide