Ferrets

Ferrets (Mustela putorius furo) are thought to be a domesticated form of the European polecat (M. putorius) and, not surprisingly, have a history extending back alongside the domestic rabbit.

Consultation and handling

Ferrets vary markedly in their temperament; working ferrets are perhaps slightly more unpre­dictable, whereas pet ferrets are usually well handled and unlikely to bite unless provoked. When handling a ferret, it can be easily restrained around the neck; a towel can be used— draped over the body—before grasping the neck to protect from scratching. For those ferrets determined to bite, scruffing and holding with all four legs off the table will usually relax them to allow a reasonable examination.

Many ferrets intensely enjoy certain commercially available dietary supplements (e.g., 8 in 1 FerreTone) to the extent that they will readily tolerate some procedures such as electrocar­diography as long as they are supplied with a steady stream of product to lick.

Always weigh the ferret whenever examined to monitor weight trends. A healthy ferret aboveground walks with a dorsal flexure in its back. Hind-leg paresis can be a nonspecific sign of ill health in the ferret due to weakness of the muscle groups needed to maintain this position.

Odor is a feature of ferret life and is likely to be used for transmitting and receiving infor­mation about individuals, such as identification, age, sex, and sexual readiness. Most of this smell comes from the sebaceous skin glands, which regress following routine castration, ovariohysterectomy or deslorelin implantation. The anal sacs can produce a strong-smelling liquid, but this tends only to occur if the ferret is frightened. Therefore, routine anal gland removal ("descenting") of ferrets is largely pointless and could constitute unnecessary surgery.

Blood sampling

Suitable sites for venipuncture are the jugular, cephalic, and saphenous veins. Alternatively the ventral tail artery and veins can be used.

Blood collection from the tail in the ferret

1. The ferret is held on its back with ventral tail shaved.

2. Use a 21- or 23- gauge 25-mm needle.

3. There is a flattened area on the ventral side for the proximal 4 to 5 cm overlying the ventral concavity of the caudal vertebrae.

4. The artery there is flanked by two veins.

5. The needle is inserted at a shallow angle toward the body around 3 to 4 cm from the base of the tail.

If blood sampling is done under isoflurane anesthetic, note that isoflurane has been linked with a reduction in packed cell volume (PCV), hemoglobin level, and RBC count. In addition, one may need to centrifuge the blood for 20% longer than for other species and collect 3? plasma volume required. This may be due to increased erythropoiesis from the spleen.

The typical WBC count is neutrophilic with Keep warm.

Cardiopulmonary resuscitation

1. Intubate and ventilate at 20 to 30 breaths/min.

2. Reverse medetomidine (if used) with atipamezole at same volume as administered medetomidine IM.

3. If cardiac arrest, external cardiac massage at around 100 compressions/min.

4. Epinephrine at

a. 0.2 to 0.4 mg/kg diluted in sterile saline intratracheal.

b. 0.2 mg/kg intracardiac, IV or IO

5. Fluid therapy (see above)

6. If bradycardic, atropine at 0.05 mg/kg IV or 0.05 to 0.1 mg/kg intratracheal.

Skin disorders

Ferrets undergo a seasonal cycle of hair thinning that occurs during the summer months. There are multiple sebaceous glands in the skin that impart both a greasy feel to the coat and the typical musky ferret smell. These glands are more numerous in males, and in some albino males they can produce a dirty, yellow appearance. Neutering and deslorelin implantation causes some atrophy of these glands, reducing the odor.

Pruritus

• Ectoparasites

• Note that Sarcoptes scabiei presents in two clinical patterns—generalized and localized to the feet.

• Hyperadrenocorticism (see Endocrine Disorders)

• Pyoderma

• Staphylococci

• Streptococci

• Corynebacterium

• Pasteurella

• Actinomyces

• Escherichia coli

• Dermatophytosis

Alopecia

• Self-mutilation

• Hormonal

• Hyperadrenocorticism (see Endocrine Disorders, Fig. 1-1)

• Ovarian pedicle neoplasia (Patterson et al 2003)

• Alopecia at tail base (hyperestrogenism—see Reproductive Disorders)

• Seasonal alopecia

• Pregnancy toxemia/ketosis (see Reproductive Disorders)

• Dermatophytosis

• Mucormycosis (Absidia corymbifera)

• Biotin deficiency (feeding raw eggs)

Scaling and crusting

• Canine distemper virus (CDV—see Systemic Disorders)

• Pyoderma

• Dermatophytosis

Fig 1-1. Bilateral symmetrical alopecia in a female ferret with hyperadrenocorticism.

Erosions and ulceration

• Excoriation from self-inflicted trauma if pruritic

• Bite wound

• Blastomyces dermatitidis

• Cryptococcus bacillisporus

Nodules and nonhealing wounds

• Abscess

• Hematoma

• Granuloma

• Swollen mammary glands

• Painful, discolored (acute mastitis, neoplasia—see Reproductive Disorders)

• Nonpainful, normal color (chronic mastitis, neoplasia—see Reproductive Disorders)

• Swollen, discharging swellings around neck (actinomycosis)

Changes in pigmentation

• Dry, dull coat (poor diet)

• CDV (see Systemic Disorders)

• Swollen, painful mammary glands; may turn black (gangrenous) (acute mastitis—see

Reproductive Disorders)

• Ectoparasites

• Fleas (Ctenocephalides spp.)

• Ear mites (Otodectes cynotis)

• Ticks

• Sarcoptes scabiei

• Demodex spp.

• Lynxacarus mustelae (fur mite)

• Myiasis

• Cuterebra spp.

• Hypoderma bovis

Neoplasia

• Mast cell tumor

• Sebaceous gland adenoma

• Hemangioma

• Squamous cell carcinoma

• Benign cystic adenoma

• Preputial adenocarcinoma

• Dermatofibroma

• Carcinoma

• Fibroma

• Fibrosarcoma

• Histiocytoma

• Sarcoma

• Lymphoma (rarely presents as a skin lesion)

Findings on clinical examination

• Thick brown, waxy exudate from ears (ear mites)

• Pruritis and inflammation limited to feet (Sarcoptes scabiei)

• Hyperkeratosis of the footpads and erythematous cutaneous rashes in the inguinal area and under the chin. Oculonasal discharge (CDV)

• Swellings with discharging sinuses in the cervical area (bite wounds, actinomycosis)

Investigations

1. Microscopy: examine fur pluck, acetate strips, or skin scrapes to affected area and examine for ectoparasites.

2. Examine material from ear canals for Otodectes cynotis.

3. Bacteriology and mycology: hair pluck or swab lesions for routine culture and sensitivity

4. Fine-needle aspirate followed by staining with rapid Romanowsky stains

5. Biopsy obvious lesions.

6. Ultraviolet (Wood's) lamp—positive for Microsporum canis only (not all strains fluoresce)

7. Radiography

8. Routine hematology and biochemistry

9. Culture and sensitivity

10. Endoscopy

11. Biopsy

12. Ultrasonography

TreatmentZspecific therapy

• Fleas

• Commercial flea treatments at cat dose rates

• Lufenuron at 10 mg/kg SC or 30 mg/kg PO in food

• Topical spot-on preparations of 10% (w/v) imidacloprid (Advantage, Bayer) at

10 mg/kg and 10% (W/V) imidacloprid/50% (w/v) permethrin (Advantix, Bayer) at

10 mg/kg have proven efficacious at flea control on the mink (Larsen et al 2005) and should be safe on the ferret. Environmental flea control will be required.

• Sarcoptic mange

• Ivermectin at 0.2 to 0.4 mg/kg SC every 7 to 14 days to resolution

• Selamectin at dose for ear mites (see Ear Mites below)

• Moxidectin at dose for ear mites (see Ear Mites below)

• Ear mites

• Topical antiparasitic ear preparations, although the small size of the ear canal may prevent effective treatment.

• Selamectin spot-on at 6 mg/kg as a topical spot-on preparation; has proven safe at

45 mg/adult ferret (Stronghold Cat, Pfizer) (Revolution, Zoetis) (Miller et al 2006)

• 10% imidacloprid/1% moxidectin (Advocate (UK) Revolution, Zoetis (USA), Bayer) at 1 drop per 100 g body weight (Beck 2007)

• Cross-infection with dogs and cats in the same household may occur.

• Demodex

• Amitraz (0.05%) topically every 7 days

• Myiasis

• Remove larvae.

• Clean and debride wounds.

• Systemic parasiticide (e.g., ivermectin, selamectin, imidacloprid)

• Covering antibiosis

• Supportive therapy if necessary

• Pyoderma, bacterial dermatitis, and cellulitis

• Shave any badly infected areas.

• Apply topical and parenteral antibiotics.

• Cleaning with chlorhexidine solution may be beneficial.

• Surgical removal of abscesses

• Bites and lacerations

• Clean and debride well.

• Covering broad-spectrum antibiosis

• Actinomycosis

• Debride and clean lesion.

• Appropriate antibiosis

• Dermatophytosis, Blastomyces, and mucormycosis

• Miconazole/chlorhexidine (Malaseb, Leo) shampoo—bath once daily

• Griseofulvin at 25 mg/kg PO s.i.d. for 21 to 30 days

• Itraconazole at 25 to 33 mg/kg PO s.i.d. for 30 days

• Ketoconazole at 10 to 30 mg/kg PO s.i.d. for 60 days

• Cryptococcus

• Amphotericin B, at 150 pg/kg i.v. 3 times weekly for 2-4 months

• Seasonal alopecia

• In breeding season (March to August); will regrow

• Hair loss occurring in winter and early spring may be an early indicator of hyperadrenocorticism (see Endocrine Disorders).

• Self-mutilation

• Lack of suitable hiding places or other stressors

• Females plucking hair for nesting

• Biotin deficiency

• Associated with diets >10% raw egg

• Reduce egg intake and supplement with proprietary vitamin formula.

• Neoplasia

• Aggressive surgical resection

• Chemotherapy may be attempted. Accessible cutaneous tumors can be treated by injecting cisplatin directly into the tissue mass on a weekly basis as a debulking exercise.

Respiratory tract disorders

Ferrets constantly investigate and monitor their environment by sniffing all available surfaces; hence sneezing is not uncommon.

Viral

• CDV (see Systemic Disorders)

• Influenza virus (orthomyxovirus)

Bacterial

• Bacterial pneumonias

• Streptococcus zooepidemicus, S. pneumoniae, group C and G streptococci

• E. coli

• Klebsiella pneumoniae

• Pseudomonas aeruginosa

• Bordetella bronchiseptica

• Listeria monocytogenes

• Mycobacteriosis: M. bovis, M. abscessus

Fungal

• Fungal mycoses (e.g., Aspergillus—rare)

Protozoal

• Pneumocystis jiroveci

Parasitic

• Angiostrongylus vasorum (lungworm)

Neoplasia

• Lymphoma/lymphosarcoma (see Systemic Disorders)

• Lung metastases

Other noninfectious problems

• Cardiac disorders

• Hyperestrogenism (see Reproductive Disorders)

• Gastric bloat (see Gastrointestinal Tract Disorders)

Findings on clinical examination

• Sneezing

• Coughing

• Dyspnea and tachypnea

• Air hunger

• Cyanosis

• Respiratory signs varying from a catarrhal rhinitis to pneumonia, plus oculonasal discharge, hyperkeratosis, and gastrointestinal signs (CDV)

• Pale mucous membranes (anemia—see Cardiac and Hematologic Disorders)

• Ocular and/or nasal discharges (CDV, influenza)

• Lethargy, dullness, depression, and pyrexia in addition to upper respiratory signs (influenza)

• Coughing, dyspnea, exercise intolerance, anorexia, and weight loss (interstitial pneumonia and hemorrhage); pulmonary hypertension and congestive heart failure; coagulopathy can result in anemia, melena, subcutaneous hematomas, and CNS signs (Angiostrongylus vasorum).

Investigations

1. Tracheal wash/bronchoalveolar lavage

2. Culture and sensitivity

3. Cytology

4. Pleural tap and cytology

5. Radiography

a. Mediastinal lymphoma with pleural effusions occurs more commonly in younger ferrets.

6. Routine hematology and biochemistry

a. Anemia; eosinophilia: Angiostrongylus vasorum

7. Serology for CDV, Mycobacterium bovis, influenza (hemagglutination inhibition tests and enzyme-linked immunosorbent assays [ELISAs] may be of benefit in detecting influenza A)

a. Serology, polymerase chain reaction (PCR) fecal examination for Angiostrongylus vasorum

8. Endoscopy

9. Biopsy

10. Ultrasonography

Management

1. Provide supportive treatment (e.g., fluids), covering antibiosis.

2. Reduce stress levels. Hospitalize away from dogs and noisy cats; keep in darkened position.

3. Supply oxygen, preferably via an oxygen tent.

4. Mucolytics (e.g., bromhexine, N-acetylcysteine) may be useful.

5. Pleural effusion—consider tube thoracostomy.

TreatmentZspecific therapy

• CDV (see Systemic Disorders)

• Influenza

• Ferrets are very susceptible to the human influenza virus as well as the H5N1 strain (Govorkova et al 2005), showing pyrexia, anorexia, weight loss, lethargy, diarrhea, and death.

• It can be transmitted from ferret to ferret and, more important, from human to ferret.

• It may also be a potential zoonosis.

• Usually transient and self-limiting—most ferrets will recover without treatment, although the H5N1 strain is potentially fatal.

• Supportive care, including fluids and nutritional support, can be given if necessary.

• Diphenhydramine at 1 mg/kg PO b.i.d.

• Amantadine at 6.0 mg/kg PO b.i.d. or by nebulizer

• Covering antibiosis to prevent secondary infections (mucopurulent oculonasal discharges)

• Bacterial pneumonia

• Appropriate antibiosis

• Otherwise care as described under Management

• Mycobacteriosis

• Potential zoonosis, so consider euthanasia.

• M. abscessus has been successfully treated with clarithromycin (Lunn et al 2005).

• Fungal mycoses

• Ketoconazole at 10 to 30 mg/kg PO s.i.d. for 60 days

• plain Amphotericin B

- 0.25 to 1.0 mg/kg IV s.i.d. or every other day until a total dose of 7 to 25 mg has been given

- For Cryptococcus, 150 pg/kg i.v. 3 times weekly for 2-4 months

• Itraconazole at 25 to 33 mg/kg PO s.i.d. long term

• Pneumocystis jiroveci

• Pentamidine isethionate at 3 to 4 mg/kg on alternate days for a maximum of 10 treatments

• Co-trimoxazole at 30 mg/kg PO or SC b.i.d.

• Angiostrongylus vasorum

• Uncommon but is an emerging disease of dogs in Europe; has been recorded in ferrets (Helm et al 2010)

• Adult worms in pulmonary artery and right ventricle. Low burdens may be asymptomatic.

• Moxidectin 1.0 to 4.0 mg/kg as Advocate (UK), Advantage Multi (USA) (Europe) or Advantage Multi for Cats (USA) 40 mg imidacloprid + 4 mg moxidectin spot-on solution for small cats and ferrets (Bayer). May need to be repeated monthly.

• Avoid access to intermediate hosts, such as terrestrial mollusks like slugs, and paratenic hosts.

Gastrointestinal tract disorders

Permanent dental formula of the ferret

I:-, C:-, PM :-, M :-

3 1 3 2

The permanent incisors erupt at around 6 to 8 weeks while the other permanents are usually through by 10 weeks.

Deciduous dental formula of the ferret

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C:1,

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Disorders of the oral cavity

• Dental disease

• Periodontal disease, gingivitis, and dental tartar not uncommon

• May be associated with moist or semi-moist foods

• Fractured canines are commonly found but are rarely painful unless the pulp is exposed.

• If pulp/dentin is red/pink (recently exposed) or tan colored and the tooth color has been retained, these teeth can potentially be saved with an amalgam filling (Johnson- Delaney and Nelson 1992).

• If pulp/dentin is dull gray, it is likely to be devitalized; if black, it is necrotic.

• Manage as for dog and cat dental disease.

• Salivary mucocele

• Facial swellings.

• Aspirate sample for analysis, including cytology (differentiate from abscess, neoplasia, hematoma).

• Surgical resection of the affected gland is the best option to prevent recurrence. Zygomatic and buccal glands are commonly affected—may require removal of zygomatic arch to aid surgical resection (Mullen 1997).

• Neoplasia

• Salivary gland adenocarcinoma

• Investigate as for salivary mucocele.

• Oral fibrosarcoma

- Solid mass from oral mucosa that gradually grows over the teeth, eventually interfering with feeding

- Surgical resection, although it often becomes a debulking exercise as complete resection is difficult

Differential diagnoses for gastrointestinal disorders

Viral

• CDV (see Systemic Disorders)

• Rotavirus

• Influenza virus (transient diarrhea)

• Coronavirus (epizootic catarrhal enteritis, green slime disease)

Bacterial

• Lawsonia intracellularis (proliferative bowel disease, PBD)

• Helicobacter mustelae

• Salmonellosis, esp. S. typhimurium, S. newport, and S. choleraesuis

• Campylobacter jejuni

• Clostridium perfringens (possible cause of gastric bloat)

• Mycobacteriosis, esp. M. bovis and M. avium

• Anal gland abscess

Fungal

• Cryptococcus neoformans var. grubii (Malik et al 2002)

Protozoal

• Isospora

• Giardia

• Cryptosporidium

Parasitic

• Toxascaris (uncommon)

• Toxocara (uncommon)

• Ancylostoma (uncommon)

• Cestodes (uncommon)

Neoplasia

• Lymphoma/lymphosarcoma (see Systemic Disorders)

• Polyps

• Adenocarcinoma

• Anal gland neoplasia

Other noninfectious problems

• Eosinophilic gastroenteritis (EGE)

• Megaesophagus

• Foreign body

• Trichobezoar (hairball)

• Gastric ulceration (may be iatrogenic, e.g., NSAID overdose)

• Gastric bloat

• Rectal prolapse

• Anal sac impaction

Findings on clinical examination

• Diarrhea (with or without blood/melena; for melena, see also Urinary Disorders)

• Green diarrhea (epizootic catarrhal enteritis—see Hepatic Disorders)

• Vomiting/gagging

• Dehydration

• Anorexia

• Dysphagia

• Hypersalivation

• Teeth grinding and abdominal pain

• Weight loss

• Gastric distension, dyspnea, cyanosis

• Hemorrhagic diarrhea in young ferrets; occasional rectal prolapse (Isospora)

• Fecal tenesmus (especially in ferrets under 1 year of age) (PBD)

• Thickened bowel palpable (PBD, EGE)

• Colitis-like signs—increased amount of mucus and frank blood in the stool (PBD, EGE)

• Vomiting (± blood from erosions or ulcers), black tarry diarrhea (small intestine), watery diarrhea with frank blood (large intestine), and weight loss (EGE)

• Enlarged mesenteric lymph nodes may be palpable (EGE).

• Palpable foreign body

• Gastrointestinal signs are rare with CDV, but it should be considered if accompanied by oculonasal discharge, hyperkeratosis, and respiratory signs.

Investigations

1. Fecal examination

a. Isospora oocysts

b. Modified Ziehl-Neelsen (MZN) staining for Cryptosporidium

c. Nematode eggs

2. Radiography

a. Megaesophagus (contrast study with barium at 10 mL/kg PO)

b. Foreign body

3. Routine hematology and biochemistry

a. Eosinophilia—10% to 35% (normal range 3% to 5%) (EGE [eosinophilia not always present], parasitism)

b. Anemia (severe gastric ulceration—see also Cardiovascular and Hematologic Disorders)

c. Hypoalbuminemia (severe intestinal disease, including PBD, EGE, and Helicobacter)

4. Serology for CDV, Helicobacter mustelae

5. PCR for Lawsonia, ferret coronavirus

6. Culture and sensitivity

7. Endoscopy

a. Gastric ulceration (also biopsy)

8. Biopsy

a. Lymphoma

b. Helicobacter

9. Ultrasonography

a. Enlarged mesenteric lymph node (EGE)

Management

1. Fluid therapy (see Nursing Care)

2. If vomiting:

a. Do not feed for 6 to 12 hours and use antiemetics (e.g., metoclopramide at 0.2 to 1.0 mg/kg SC t.i.d.).

b. Monitor blood glucose—consider dextrose/saline fluids.

TreatmentZspecific therapy

1. Rotavirus

a. Supportive treatment only

b. Usually in young ferrets 2 to 6 weeks old

2. Influenza virus (see Respiratory Tract Disorders)

3. Epizootic catarrhal enteritis

a. Supportive treatment plus covering antibiotics

4. Bacterial diseases, including salmonellosis

a. See Management above.

b. Appropriate antibiosis

5. PBD

a. Chloramphenicol at 50 mg/kg IM, SC, or PO b.i.d.

b. Metronidazole at 20 mg/kg PO b.i.d. for 3 weeks

6. Helicobacter mustelae

a. A common isolate from gastric ulcers, its significance is uncertain.

b. Combination therapy of:

i. Amoxicillin at 10 to 20 mg/kg PO or SC b.i.d.

ii. Metronidazole at 20 mg/kg PO b.i.d.

iii. Bismuth subsalicylate at 0.25 to 1.0 mL/kg PO q.i.d.

7. Mycobacteriosis

a. Potential zoonosis

b. Consider euthanasia.

8. Cryptococcus

a. Amphotericin B at 150 pg/kg i.v. 3 times weekly for 2-4 months

9. Isospora

a. Sulfadimethoxine at 30 mg/kg PO b.i.d.

b. Amprolium at 119 mg/kg PO in food or water daily for 7 to 10 days

10. Giardia

a. Metronidazole at 10 to 20 mg/kg PO b.i.d. for 10 days

11. Cryptosporidium

a. Often subclinical

b. No effective treatment recognized

c. Potentiated sulfonamides may be of use, as may nitazoxanide at 5 mg/kg PO s.i.d.

d. Potential zoonosis, so consider euthanasia.

Nutritional disorders

Ferrets have a rapid gut transit time of around 5 hours. They should be fed a diet high in protein and fat and low in fiber.

Ferret nutrition

1. Protein requirement is around 30% to 40% and the quality must be good—in the region of 85% to 90% digestable. Diets high in plant proteins predispose to urinary calculi (see Urinary Disorders).

2. Fat levels should be 15% to 30%.

3. Carbohydrate levels should be below 40%. The rapid gut transit time and low brush border enzyme levels present in ferrets result in a poor ability to utilize carbohydrates, and the animal will fail to thrive if the carbohydrate concentration exceeds 40%. Note that the only carbohydrates that ferrets would normally have access to are in the gut contents of their prey.

It can be normal for ferrets to undergo seasonal weight increases, under the influence of photoperiod. This is normal and should not be a cause of concern.

• Hypoglycemia from starvation (see Pancreatic Disorders for management)

• Nutritional osteodystrophy

• Young kits fed on a low-calcium diet (day-old chicks)

• Deformities of the long bones, soft jaw

• Supplement with dietary calcium and vitamin D₃ supplement.

• Hepatic lipidosis

• Linked to long-term anorexia

• Aggressive fluid therapy

• Parenteral nutrition with glucose and vitamins

• Assisted feeding by syringe (see Nursing Care)

• Calcium gluconate PO or propylene glycol PO may be of use.

• Dexamethasone at 0.2 mg/kg IV, SC, or PO

Hepatic disorders

Nutritional

• Hepatic lipidosis

• Copper toxicosis

• Ketosis (see Reproductive Disorders)

Neoplasia

• Lymphoma/lymphosarcoma (see Systemic Disorders)

• Metastases (e.g., insulinoma)

• Hemangiosarcoma

• Adenocarcinoma

• Hepatocellular adenoma

• Bile duct cyst adenoma

• Biliary carcinoma

Other noninfectious problems

• Lymphocytic hepatitis

• Cholangiohepatitis

Findings on clinical examination

• Reduced or loss of appetite

• Vague signs of ill health

• Abnormal feces

• Hepatomegaly

• Jaundice (rare)

• Ascites

• Bile-tinged (green) diarrhea

• Lethargy, hypothermia, hyperthermia, jaundice (copper toxicosis)

• Seizures

Investigations

1. Radiography

2. Routine hematology and biochemistry

a. Raised liver enzymes; alanine transaminase (ALT) usually >275 IU/L (normal 78 to 289 IU/L); alkaline phosphatase (ALP) may be raised; total bilirubin levels often normal

3. Culture and sensitivity

4. Endoscopy

5. Biopsy

6. Ultrasonography

Management

1. Fluid therapy (see Nursing Care)

2. Lactulose at 150 to 750 mg/kg PO b.i.d. or t.i.d.

3. Milk thistle (Silybum marianum) is hepatoprotectant. Dose at 4 to 15 mg/kg PO b.i.d. or t.i.d.

TreatmentZspecific therapy

• Hepatic lipidosis (see Nutritional Disorders)

• Copper toxicosis

• Penicillamine at 10 mg/kg PO s.i.d.—offer as divided dose if vomiting occurs.

• Trientine at 10 mg/kg PO b.i.d.

• Supportive therapy

• Possibly inherited susceptibility

• Poor prognosis

Splenic disorders

• Splenomegaly can be a normal finding in ferrets; however, it is also found in a range of disorders, the most significant of which are:

• Hemangiosarcoma and hemangioma

• Cardiac disease (see Cardiovascular and Hematologic Disorders)

• Lymphoma/lymphosarcoma (see Systemic Disorders)

• Insulinoma (see Pancreatic Disorders)

• Aleutian disease (see Systemic Disorders)

• Idiopathic splenomegaly

Treatment

• Address underlying cause.

• Splenectomy

• Hypersplenism

• Splenic rupture

• Splenic torsion

• Neoplasia

• Splenitis

Pancreatic disorders

Neoplasia

• Insulinoma (pancreatic beta cell tumor)

• Exocrine pancreatic adenocarcinoma

Other noninfectious problems

• Diabetes mellitus

Findings on clinical examination

• Signs of an insulinoma include transient episodes of inactivity during which the ferret is unresponsive to external stimuli, hind-limb weakness, and eventually seizures, coma, and death.

• Ataxia and hind-limb paresis

• Lethargy

• Hypersalivation

• “Glazed-eye” appearance

• Abdominal distension

• Pain

• Abdominal mass palpable

Investigations

1. Radiography

2. Routine hematology and biochemistry (Table 1-4)

a. Provisional diagnosis of an insulinoma is based on a low fasting blood glucose sample (a 4-hour fast will suffice). Insulinomas often also show

neutrophilia, leukocytosis, and monocytosis plus raised ALT and aspartate transaminase (AST).

b. Blood insulin levels

3. Culture and sensitivity

4. Urinalysis

a. Glycosuria/ketonuria

5. Endoscopy

6. Exploratory surgery and biopsy

7. Ultrasonography

Management

1. Treatment of hypoglycemia

Hypoglycemia

1. Rub honey or sugared water onto the gingiva, taking care not to get bitten.

2. Give 0.5- to 2.0-mL bolus IV of 50% dextrose solution slowly (so as not to overstimulate a possible insulinoma).

3. Provide fluid therapy (see Nursing Care) with 5% dextrose infusion.

4. If ferret fails to respond, can give shock dose of dexamethasone at 4 to 8 mg/kg IV or IM once only.

5. Diazepam at 1 to 2 mg IV as needed to control if are seizures persistent.

TreatmentZspecific therapy

• Diabetes mellitus

• Neutral protamine Hagedorn (NPH) insulin at a starting dose of 0.1 IU/ferret SC

b. i.d. until stabilized. Monitor blood glucose levels.

• Maintain on ultralente insulin s.i.d.

• Insulinoma

• Surgical resection

- Fluid therapy with 5% dextrose saline

- Partial resection or nodulectomy

- Metastasis is very common.

• Medical management

- Prednisolone 0.5 to 2.0 mg/kg PO b.i.d., raising until clinical signs subside

- Diazoxide at 5 to 10 mg/kg PO b.i.d. (may induce vomiting and anorexia)

• Medical management may give 6 to 18 months of control of clinical signs, although it will not prevent further growth and spread of the insulinoma.

• Hyperglycemia following pancreatic surgery will usually resolve within 2 weeks and requires no action.

• Pancreatic exocrine adenocarcinoma

• Readily metastasize. Surgery is a possible option, but metastasis is highly likely before diagnosis is confirmed.

Cardiovascular and hematologic disorders

Viral

• Aleutian disease (see Systemic Disorders)

Bacterial

• Bacteremia/septicemia

• Endocarditis

Protozoal

• Toxoplasma gondii (myocarditis—see Neurologic Disorders)

Parasitic

• Dirofilaria immitis (heartworm)

• Angiostrongylus vasorum (lungworm—see Respiratory Tract Disorders)

Neoplasia

• Lymphoma (see Systemic Disorders)

Other noninfectious problems

• Cardiomyopathy

• Dilative

• Hypertrophic

• Valvular heart disease

• Hyperestrogenism (see Reproductive Disorders)

• Gastric ulceration (see Gastrointestinal Tract Disorders)

• Congenital disorders

Findings on clinical examination

• Cyanosis or pallor of the mucous membranes

• Anemia (hyperestrogenism, gastric ulceration)

• Slow capillary refill time

• Dyspnea

• Precordial thrill

• Abormalities of femoral arterial pulse, including weakness, irregularities, pulse deficits

• Arrhythmia

• Lack of thoracic percussion with auscultation

• Abnormal lung sounds

• Abnormal heart sounds

• Exercise intolerance

• Ascites

• Hepatomegaly, splenomegaly

• Weight loss

• Sudden death

Investigations

1. Auscultation

2. Blood pressure: systole: 140 ± 35 mm Hg; diastole: 110 ± 31 mm Hg

3. ECG

a. Use adhesive ECG contacts designed for children; metal clips and needles are poorly tolerated in the conscious ferret.

b. Distract the ferret by offering a favored food or food supplement (e.g., 8 in 1 FerreTone).

c. Normal ferret lead II ECGs:

i. The P waves are small.

ii. The R waves are large.

iii. Short QT interval

iv. Elevated ST segment (Table 1-5)

4. Radiography

a. Vertebral heart score:

i. Thoracic radiograph taken in right lateral recumbency.

ii. Measure the long axis (LA) and short axis or width of the heart (SA) in cm.

iii. Measure the combined length of thoracic vertebrae T5-T8 in cm.

iv. Divide the sum of the axes by the thoracic vertebral measurement:

(LA + SA) cm/T5-T8 (cm)

Males: Ratio = 1.35 (SD 0.07); Females: Ratio = 1.34 (SD 0.06)

After Stepien et al (1999)

b. Pleural effusions and cardiomegaly are common findings with cardiomyopathy and dirofilariasis.

c. A globoid heart shape is often indicative of cardiac disease, usually with increased Cardiosternal contact.

d. Anterior mediastinal masses (lymphoma)

5. Ultrasonography/echocardiography

a. Normal echocardiographic values for ferrets (from Stamoulis et al 1997) (Table 1-6)

b. Detection of dirofilariasis (Sasai et al 2000)

6. Routine hematology and biochemistry

a. Microfilaria in peripheral bloodstream (uncommon) (Dirofilaria)

b. Anemia (hyperestrogenism, high ectoparasite count, Aleutian disease, gastrointestinal hemorrhage due to, e.g., gastric ulceration or gastroenteritis)

7. Serology for Dirofilaria antigen, Toxoplasma

8. Culture and sensitivity

9. Endoscopy

10. Biopsy

Management

• Reduce stress (e.g., keep in a cool, shaded or darkened area away from potential stressors such as dogs).

• Provide a high oxygen environment.

• For pleural effusion, consider tube thoracostomy.

TreatmentZspecific therapy

• Dirofilaria immitis

• Due to the small size of the ferret, even only a few worms may cause serious problems, with clinical signs ranging from heart failure to pulmonary edema.

• Treatment is also difficult because the worms may cause thromboembolisms, resulting in acute death.

• Treatment protocol

- Thiacetarsemide at 2.2 mg/kg IV b.i.d. for 2 days.

- Start heparin at 100 units/ferret SC every 24 hrs for 21 days.

- After 3 weeks stop heparin and start on aspirin at 22 mg/kg PO s.i.d. for 3 months.

- Treat concurrently for cardiac disease if appropriate.

- Alternatively try topical 10% imidacloprid/1.0% moxidectin (Advocate (UK) Advantage Multi (USA), Bayer) at 0.4 mL per ferret.

- Prevention is with ivermectin at 0.2-0.4 mg/kg SC, PO repeated after 14 days once monthly in areas where heartworm is endemic.

• Cardiomyopathies

• Dilated (congestive) cardiomyopathy

- Furosemide at 1 to 4 mg/kg b.i.d.

- Enalapril at 0.5 mg/kg PO every 48 hours. Ferrets appear very sensitive to the hypotensive effects of ACE inhibitors.

- Benazepril 0.25 to 0.5 mg/kg s.i.d. Less nephrotoxic than enalapril

- Digoxin at 0.01 mg/kg PO s.i.d.

- Nitroglycerin at 3 mm of 2% ointment applied to skin s.i.d. or b.i.d.

- Pimobendan at 0.2-1.25 mg/kg PO b.i.d.

• Hypertrophic cardiomyopathy

- Atenolol at 3.125-6.25 mg/kg PO s.i.d.

- Diltiazem at 1.5-7.5 mg/kg PO b.i.d.

• Valvular heart disease

• Treat as for dilated cardiomyopathy

• Hyperestrogenism (see Reproductive Disorders)

Systemic disorders

Viral

• Coronavirus

• CDV (see also Neurologic Disorders)

• Aleutian disease (parvovirus)

• Rabies

Bacterial

• Bacteremia/septicemia

Nutritional

• Copper toxicosis (see Hepatic Disorders)

• Ketosis (see Reproductive Disorders)

Neoplasia

• Insulinoma (see Pancreatic Disorders)

• Hyperadrenocorticism (see Endocrine Disorders)

• Lymphoma/lymphosarcoma (see also Respiratory Tract Disorders and Cardiovascular and Hematologic Disorders)

• Mesothelioma

Other noninfectious problems

• Hyperestrogenism (see Reproductive Disorders)

Findings on clinical examination

• Weight loss, dyspnea, hind-leg weakness, ascites (coronavirus, Aleutian disease, lymphoma)

• Bilateral mucopurulent ocular and/or nasal discharges—the ocular discharge dries to a crust at the eyelid margins, sealing the eyes shut (CDV)

• Hyperkeratosis of the footpads and erythematous cutaneous rashes in the inguinal area and under the chin (CDV)

• Chronic upper respiratory infections, dyspnea, general lethargy, wasting, and lymphadenopathy (lymphoma). Peripheral lymphadenopathy is more common in older animals.

• Palpable abdominal masses (splenomegaly, mesenteric and/or gastric lymph nodes) (lymphoma)

• Distended abdomen (mesothelioma)

Investigations

1. Radiography

a. Renomegaly, splenomegaly, lymphadenopathy (coronavirus)

b. Mediastinal masses, pleural effusions, abdominal masses (lymphoma) (Table 1-7)

2. Routine hematology and biochemistry

a. Persistent high WBC counts (10 ? 109/L or above) with a high lymphocyte count (lymphoma). Consider lymphoma if lymphocytosis (3.5 ? 109/L or greater) or 60% lymphocytes. Immature ferrets (85% with the presence of bands.

c. Hyperglobulinemia (coronavirus, Aleutian disease); note that not all ferrets with Aleutian disease are hypergammaglobulinemic (Une et al 2000).

d. Aleutian disease produces immune complexes that trigger renal disease, including glomerulonephritis, so renal parameters are likely to be high.

3. Bone marrow aspirate/lymph node cytology (lymphoma)

Technique for bone marrow aspirate (performed under GA)

1. Prepare at least four slides.

2. Draw some EDTA (can mix from EDTA blood tube with sterile saline).

3. Use a 5- or 10-mL syringe with around 1 mL of EDTA solution present.

4. Use an 18G or 21G 25-mm needle.

5. Identify the trochanteric fossa.

6. Grind into bone so that needle is parallel to long axis of femur.

7. Perform several aspirates—marrow appears as thick blood.

8. Apply the collected marrow to each of the slides.

9. Leave for approximately 30 seconds for bone spicules to settle onto slide.

10. With half of the slides, tip and drain away excess, including the spicules.

11. For the other half, place a clean slide across at right angles and draw across to create a “squash” preparation (but without squashing!).

12. Air dry and submit to lab.

4. Abdominal centesis and cytology

5. Serology for CDV, Aleutian disease, rabies

6. PCR for ferret coronavirus

7. Culture and sensitivity

8. Endoscopy

9. Biopsy/necropsy

a. Pyogranulomatous enteritis (coronavirus)

b. Lymphoma (especially mesenteric lymph node, peripheral lymph nodes, spleen, liver, and any abnormal organs); see Table 1-7.

c. CDV

10. Ultrasonography

Management

• See Nursing Care.

TreatmentZspecific therapy

• Coronavirus

• Symptomatic treatment only

• CDV

• The incubation period described for CDV in ferrets is from 7 to 10 days. The usual course of disease, from exposure to death, is 12 to 25 days.

• There is no treatment—consider supportive therapy including covering antibiosis. The mortality rate is close to 100%. Those that do recover are likely to die later from CNS disturbances (see Neurologic Disorders).

• Prevent by vaccination. Consult manufacturers first as some CDV vaccines derived from ferret tissue cultures may increase the risk of vaccine-induced disease. Where possible, do not use multivalent vaccines. Where CDV is endemic, an initial vaccination course of 3 injections is recommended at 6 to 8 weeks of age, 10 to 12 weeks, and 13 to 14 weeks with annual boosters to follow. If CDV is not endemic, give a single dose at 12 weeks of age with annual boosters.

• Adverse reactions to vaccination are vomiting and diarrhea (Moore et al 2005).

• CDV is readily destroyed by normal cleaning and disinfection routines.

• Rabies

• Significant zoonosis. Euthanize.

• Prevent by vaccination given at 12 weeks of age with an annual booster.

• Aleutian disease

• Many ferrets can be serologically positive for Aleutian disease but show no clinical signs.

• Supportive therapy

• Steroids may prove useful in reducing the formation and effect of the immune complexes.

• Bacteremia/septicemia

• Appropriate antibiosis

• Supportive therapy as necessary (see Nursing Care)

• Lymphoma/lymphosarcoma

• Chemotherapy protocols for small animals are regularly altered and updated, so if in doubt, consult a veterinary oncologist. The following two protocols (from Brown 1997) have been found to be useful.

- The author finds it useful to give the owner a modified copy of the above protocol adjusted to specific days/dates for administration of the different medications.

- Weekly PCV should be performed before administration of next dose of vincristine to assess degree of anemia; consider halting treatment at values below 20%.

• Palliative treatment for lymphoma

- Prednisolone at 0.5 mg/kg PO b.i.d., increasing to control signs. Note that prednisolone treatment alone is likely to make the lymphoma refractory to chemotherapy.

- Vitamin C (ascorbic acid) at 50 to 100 mg/kg PO b.i.d

- Regular annual CBC to screen for lymphoma.

• Clusters of outbreaks have occurred and in some cases may be due to a retrovirus-like agent (Erdman et al 1995), although attempted detection using feline leukemia virus (FeLV) serology, PCR, or ELISA all proved negative (Erdman et al 1996).

• Mesothelioma

• Surgical resection and chemotherapy may be worth attempting, but the prognosis is poor.

Musculoskeletal disorders

Viral

• Aleutian disease (see Systemic Disorders)

Neoplasia

• Multiple myeloma

• Chondroma

• Chondrosarcoma

• Fibrosarcoma

• Osteoma

• Chordoma

Other noninfectious problems

• Traumatic fractures

• Any causes of weakness

• See Neurologic Disorders

• See Cardiovascular and Hematologic Disorders

• See Systemic Disorders

• See Pancreatic Disorders

Findings on clinical examination

• Pain

• Lameness

• Swelling

• Hind-leg paresis/paralysis

• Small rounded mass at tip of tail (chordoma)

Investigations

1. Radiography

2. Osteolysis, pathological fractures (multiple myeloma)

3. Traumatic fractures

4. Routine hematology and biochemistry

5. Culture and sensitivity

6. Endoscopy

7. Biopsy

8. Ultrasonography

TreatmentZspecific therapy

• Multiple myeloma

• No treatment recorded.

• Traumatic fractures

• Repair using standard small animal techniques.

• Neoplasia

• Surgical resection, amputation, chemotherapy, or radiation therapy as for other small animals

• Note that chordomas may metastasize (Munday et al 2004).

Neurologic disorders

Viral

• CDV (see Systemic Disorders)

• Rabies

• Coronavirus

Bacterial

• Bacterial meningitis or other CNS infection

• Otitis media/interna

Fungal

• Cryptococcal meningitis

• Blastomycosis

Protozoal

• Toxoplasmosis

Nutritional

• Hypoglycemia

• Ketosis (see Reproductive Disorders)

Neoplasia

• Schwannoma

• Insulinoma (hypoglycemia—see Pancreatic Disorders)

• Lymphoma (see Systemic Disorders)

• T-cell lymphoma (Hanley et al 2004)

Other noninfectious problems

• Toxins

• Spinal lesions (e.g., intervertebral disc prolapse—see Lu et al 2004; fractures)

• Eosinophilic granulomatous infiltrate (as part of eosinophilic gastroenteritis—see Gastrointestinal Tract Disorders)

Findings on clinical examination

• Apparent weakness

• Posterior paralysis/paresis

• Anxiety, lethargy, constipation, bladder atony, posterior paresis, aggression (rabies)

• Seizures (uncommon except with chronic neurotrophic form of CDV)

• Salivation, muscle tremors, seizures, and coma (CDV)

• Otitis externa (see also “Ear Mites” in Skin Disorders)

Investigations

1. Full neurologic examination

2. Radiography

a. Myelography—access as for cerebrospinal fluid (CSF) tap (see below)

b. 0.25 to 0.5 mL/kg iohexol

3. Routine hematology and biochemistry

4. Serology for toxoplasmosis

5. Culture and sensitivity

Cerebrospinal fluid tap in the ferret

1. Collect as from dog or cat.

2. Sites for CSF tap are the atlantooccipital joint and lumbar (L5-L6) region.

3. 21G or 22G needle

4. Endoscopy

5. Biopsy

6. Ultrasonography

Management

• Important to differentiate from other causes of weakness (insulinoma, lymphoma etc.)

TreatmentZspecific therapy

• Rabies (see Systemic Disorders)

• Bacterial CNS infection

• Appropriate antibiosis

• Supportive care

• Fungal infections

• Ketoconazole at 10 to 30 mg/kg PO s.i.d. for 60 days

• Amphotericin B

- 0.25 to 1.0 mg/kg IV s.i.d. or every other day until a total dose of 7 to 25 mg has been given

- For Cryptococcus, 150 μg∕kg i.v. 3 times weekly for 2-4 months

• Itraconazole at 25 to 33 mg/kg PO s.i.d. long term

• Toxoplasmosis

• Clindamycin at 12.5 mg/kg PO b.i.d. for at least 2 weeks

• Combination therapy consisting of:

- Co-trimoxazole at 30 mg/kg PO b.i.d.

- Pyrimethamine at 0.5 mg/kg PO b.i.d.

- Folic acid at 3.0 to 5.0 mg/kg PO s.i.d.

• Hypoglycemia

• For management of hypoglycemic episodes, see Pancreatic Disorders.

• Orthopedic conditions

• Treat as for other small animals.

Ophthalmic disorders

The ferret eye is similar to the canine eye except that the pupil is horizontal rather than vertical.

Viral

• CDV (see Systemic Disorders)

• Influenza A (see Respiratory Tract Disorders)

Bacterial

• Salmonella spp.

• Mycobacterium spp.

Protozoal

• Toxoplasmosis (see Neurological Disorders)

Nutritional

• Hypovitaminosis A

Neoplasia

• Carcinoma of the ocular globe

Other noninfectious problems

• Salivary mucocele (see Gastrointestinal Tract Disorders)

• Hereditary cataracts

• Idiopathic cataract

• Retinal degeneration (may be hereditary)

• Foreign body

Findings on clinical examination

• Corneal ulceration

• Conjunctivitis (influenza, CDV, hypovitaminosis A)

• Nasal discharge

• Uveitis

• Corneal edema, hypopyon, and synechiae

• Cataracts

• Exophthalmos

• Megaglobus/glaucoma

• Night blindness (hypovitaminosis A, retinal degeneration)

• Periocular swelling (salivary mucocele)

• Cataracts (hereditary, hypovitaminosis A, idiopathic)

• Bilateral mucopurulent ocular and/or nasal discharges—the ocular discharge dries to a crust at the eyelid margins, sealing the eyes shut; accompanied by hyperkeratosis of the footpads and skin rashes (CDV)

Investigations

1. Ophthalmic examination

a. Schirmer tear test 5.31 ± 1.32 mm/min (Montiani-Ferreira et al 2006)

b. Central corneal thickness 0.337 ± 0.020 mm

2. Topical fluorescein to assess extent of ulceration

3. Tonometry

a. Intraocular pressure 14.5 ± 3.27 mm Hg

4. Skull radiography

5. Routine hematology and biochemistry

6. Serology for CDV, toxoplasmosis

7. Culture and sensitivity

8. Biopsy

9. Ultrasonography

TreatmentZspecific therapy

• Corneal ulceration

• Topical and systemic antibiosis

• Once infection is cleared, treat as for other small animals (e.g., scarification to encourage healing, conjunctival grafts).

• Uveitis

• Topical ophthalmic steroid or NSAID preparations

• Topical ophthalmic antibiotic preparations plus systemic antibiosis if appropriate

• Enucleation if severe

• Cataracts

• Treat for any uveitis as above.

• Cataract removal either surgically or by phacoemulsification

• Neoplasia

• Enucleation

• Toxoplasmosis (see Neurologic Disorders)

• Mycobacteriosis

• Topical chloramphenicol b.i.d. for 60 to 90 days

• Systemic antimycobacterial drugs such as rifampin, clofazimine, and clarithromycin

• Guarded prognosis; potential zoonosis so consider euthanasia

Endocrine disorders

Neoplasia

• Adrenal neoplasia

• Adrenal hyperplasia

• Adrenal adenoma/carcinoma

• Pituitary gonadotrophic adenomas (Schoemaker et al 2004)

• Insulinoma (see Pancreatic Disorders)

Other noninfectious problems

• Hyperestrogenism (see Reproductive Disorders)

Findings on clinical examination

• Hyperadrenocorticism

• Symmetrical alopecia

• Over 30% may be pruritic.

• Vulval swelling (also in spayed females)

• Male behavior in castrated males

• Dysuria in males (urethral obstruction secondary to prostatic hyperplasia)

• Splenomegaly

• Enlarged adrenal glands may be palpable (not consistent).

Investigations

1. Radiography

2. Routine hematology and biochemistry

a. Hyperadrenocorticism

i. Blood hormone levels. Which are elevated varies among individuals; cortisol is the least likely to be raised and a diagnosis is more likely if androstenedione, estradiol, and hydroxyprogesterone are measured (Table 1-10).

ii. Ideally blood samples for hyperadrenocorticism should be taken under anesthesia because manual restraint increases plasma cortisol and ACTH but decreases α-melanocyte-stimulating hormone (α-MSH) production (Schoemaker et al 2003). However, it should be noted that isoflurane (but not medetomidine) anesthesia increases the α-MSH from the pituitary gland, which may subsequently affect the concentrations of adrenal hormones.

iii. Pancytopenia (severe cases)

iv. Raised AST

v. For suspect female ferrets, differentiate from ovarian remnant (or estrus if entire) by giving 2 injections of 100 IU hCG 7 days apart. This should cause regression of vulval swelling unless the ferret has hyperadrenocorticism.

b. Thyroid levels (Table 1-11)

Thyroid stimulation test (Keeble 2001)

1. Thyroid-stimulating hormone (TSH) at 1.0 IU given IV

2. Blood for T₄ taken at 120 minutes

3. Culture and sensitivity

4. Endoscopy

5. Biopsy

6. Ultrasonography

a. Enlarged adrenal gland

b. Normal values: left adrenal gland normally 6 to 8 mm length; right adrenal gland 8 to 11 mm length. Accessory nodules of adrenal tissue occur in some individuals.

TreatmentZspecific therapy

• Hyperadrenocorticism

• The disease is linked to luteinizing hormone (LH) effects on the sex steroid- producing cells of the adrenal cortex (Schoemaker et al 2002), which in turn may explain the predisposing factor of early age of neutering.

• Treatment of choice is deslorelin implant: 4.7 mg lasts up to 12 months while 9.4 mg implant lasts from 16 months up to 4 years (NOAH Suprelorin datasheet).

• The protective effects of deslorelin implants and their ease of use mean that where they are available, castration and ovariohysterectomy are no longer recommended for ferrets.

• Other medical management

• Mitotane

• Trilostane at 2 mg/kg PO s.i.d.

• Leuprolide acetate at 100 pg/kg SC every 21 to 30 days

• Ketoconazole ineffective at 15 mg/kg b.i.d. (cited in Keeble 2001)

• Temporary cessation of clinical signs due to reduced hormone levels can be achieved with deslorelin, given as a single, slow-release 3-mg implant, with an average of 13.7 ± 3.5 months to recurrence of signs (Wagner et al 2005).

• Surgical management (adrenalectomy)

• Surgery is no longer the treatment of choice.

• In cases of bilateral adrenal disease, then either completely remove one (the left is easiest) and perform a subtotal adrenalectomy on the other (right) with subsequent medical management, or consider medical management only.

• If bilateral adrenalectomy, consider the use of supplementary glucorticoids (prednisolone at 0.1 mg/kg PO s.i.d.) [Martorell et al 2005] for several days post surgery to prevent hypoadrenocorticism. Monitor serum electrolyte ranges and titrate to effect; partial adrenalectomy or presence of accessory nodules may result in continued normal electrolyte levels without treatment.

• Temporary tube cystotomy may be beneficial in those cases with urinary obstruction from prostatic hyperplasia/prostatic cysts (Nolte et al 2002). Removal is after 5 to 10 days.

• Gonadotrophic adenomas

• Unknown significance

Urinary disorders

Viral

• Aleutian disease (see Systemic Disorders)

Bacterial

• Cystitis

Nutritional

• Urolithiasis (males > females) (see also Reproductive Disorders)

Neoplasia

• Lymphoma (see Systemic Disorders)

• Transitional cell carcinoma

• Renal carcinoma

Other noninfectious problems

• Chronic interstitial nephritis

• Hydronephrosis

• Renal cysts

• Prostatic hyperplasia (see "Hyperadrenocorticism" in Endocrine Disorders)

• Gentamicin toxicity

Findings on clinical examination

• Depression

• Anorexia/weight loss

• Polydipsia/polyuria

• Oral ulceration

• Hematuria (urolithiasis, cystitis, neoplasia)

• Hind-leg weakness

• Melena

• Dysuria/polyuria

• Urine dribbling, wet perineum, constant licking at genitalia (urolithiasis)

• Painful urination, stranguria (urolithiasis, cystitis)

• Death

• Palpable abnormalities

• Distended bladder (urethral obstruction)

• Cystic calculi/sand

Investigations

1. Urinalysis (normal urine parameters) (Table 1-12)

a. Magnesium ammonium phosphate (struvite) crystals (urolithiasis)

b. Ketonuria (ketosis—see Reproductive Disorders)

2. Radiography

a. Useful to differentiate uncomplicated cystitis from urolithiasis

b. Contrast studies (pyelography, double contrast bladder studies, pneumocystographies)

3. Routine hematology and biochemistry

a. With renal disease, urea can be >42.5 mmol/L in renal disease (normal 10 to 15 mmol/L), but creatinine is rarely raised unless renal disease is severe and long-standing.

b. Phosphorus often raised with renal disease

c. Nonregenerative anemia (advanced renal disease)

d. GFR evaluation (from Hillyer 1997) (Table 1-13)

4. Cytology

a. Renal casts, neoplastic cells

5. Culture and sensitivity

6. Endoscopy

7. Biopsy

8. Ultrasonography

Management

1. Fluid therapy (see Nursing Care)

2. Appropriate antibiosis

TreatmentZspecific therapy

• Renal cysts

• No treatment

• If large, painful, and unilateral, consider nephrectomy.

• Hydronephrosis

• Nephrectomy

• Some cases may be linked to accidental ureteral occlusion during routine ovariohysterectomy.

• Urolithiasis

• If urethral obstruction:

- Attempt catheterization (can be difficult in males due to J-shaped os penis).

- Cystocentesis

- Surgical cystotomy

- If unable to clear urethra, create a perineal urethrostomy.

• Cystic calculi

• Cystotomy

• Submit any stones/sand for analysis.

• Administer antibiosis (usually has accompanying cystitis) and other supportive care.

• Note that diets high in plant protein (especially dog food or poor-quality cat food) may predispose ferrets to urinary calculi formation as well as urinary bacterial infections.

• Change diet to commercial ferret food or high-quality cat food.

• Neoplasia

• Transitional cell carcinoma of the bladder: surgery is difficult because cancer is often diffuse. Chemotherapy may prove useful.

• Renal carcinoma

• Nephrectomy

Reproductive disorders

Ferrets are induced ovulators; ovulation occurs 30 to 40 hours after copulation. Failure to mate can result in a prolonged estrus (up to 6 months) and a resultant aplastic anemia (see "Hyperestrogenism" below). Estrus is indicated by a pronounced swollen vulva (Fig. 1-2); any female in season for longer than 1 month is considered at risk of hyperestrogenism.

Fig 1-2. Swollen vulva of a ferret in estrus.

Males have a J-shaped os penis.

Where available, the routine use of deslorelin implants has superseded routine castration and ovariohysterectomy of ferrets due to its ease of administration and its protective effects against hyperadrenocorticism (see Endocrine Disorders).

Bacterial

• Prostatitis

• Metritis/pyometra

• Mastitis (Staphylococcus spp., coliforms)

• Staphylococcus intermedius (chronic mastitis)

Nutritional

• Ketosis/pregnancy toxemia (in pregnant jills)

Neoplasia

• Hyperadrenocorticism (see Endocrine Disorders)

• Prostatic hyperplasia and prostatic cysts

• Testicular neoplasia

• Sertoli cell tumors

• Interstitial cell tumors

• Prostatic carcinoma

• Ovarian stump neoplasia

• Undifferentiated carcinoma

• Leiomyoma

• Fibrosarcoma

• Ovarian teratoma

• Mammary cystic carcinoma

• Uterine adenoma

Other noninfectious problems

• Hyperestrogenism

• Failure to mate

• Adrenal neoplasia (see Endocrine Disorders)

• Ovarian remnant following ovariohysterectomy

• Urolithiasis (in pregnant jills)

• Dystocia

• Low litter size (unborn kits will die after 43 days' gestation)

• Physical abnormalities

• Large kits

• Deformed/anasarca kits

• Maternal pelvic abnormalities

Findings on clinical examination

• Vulval hyperplasia (hyperestrogenism, hyperadrenocorticism, estrus, ovarian remnant/ neoplasia)

• Other signs of hyperestrogenism include tachypnea, anemia (pale mucous membranes), ecchymotic and petechial hemorrhages, melena, weakness, hind-limb paresis, secondary infections, and alopecia at tail base.

• Vaginal prolapse (may accompany rectal prolapse) (urolithiasis)

• Swollen uterus palpable; vaginal discharge may, but not always, be present (pyometra, metritis)

• Dysuria/stranguria (prostatic hyperplasia)

• Alopecia and pruritis in entire male ferret (Sertoli cell tumor)

• Swollen, painful, discolored mammary glands (acute mastitis, neoplasia)

• Swollen but otherwise normal mammary glands (chronic mastitis)

• Lethargy dehydration in pregnant female (jill); melena may be present; hair loss (pregnancy toxemia)

Investigations

1. Radiography

a. Prostatic hyperplasia (will also help differentiate from urolithiasis)

2. Routine hematology and biochemistry

a. PCV (normal 46% to 61%). For hyperestrogenism, PCV can be used as a prognostic indicator (from Keeble 2001) (Table 1-14).

b. Other blood values consistent with hyperestrogenism reflect a pancytopenia and include a normocytic normochromic or macrocytic hypochromic anemia plus a thrombocytopenia, neutropenia, eosinopenia.

c. Pregnancy toxemia/ketosis

d. In additon to low blood glucose (25 Good Ovariohysterectomy hCG or GnRH injection 15-25 Guarded hCG or GnRH injection Supportive care before surgery at 21 days (g) 100 Age of eyes opening 30-35 days Age of weaning 6-8 weeks