Housing

Ferrets may be housed singly or in groups, inside or outside of a house. When kept outdoors, however, they must be protected from extreme weather. Ferrets have difficulty tolerating temperatures above 90° F or below 20° F, and appropriate precautions must be taken to prevent their exposure to these extremes.³ A multilevel wire cage with smooth or wire flooring is appropriate. Glass tanks are not recommended, as they do not provide adequate ventilation. A 24″ ×24″ ×18″ cage is a suitable sized enclosure for a ferret. A cage con-structed out of a nonporous product is ideal for purposes of disinfection.

Because of their excretory habits, ferrets can be easily trained to use a litter box. This can be achieved in the cage and made readily available throughout the house when the ferret is allowed to roam free. Ferrets also enjoy a small, dark place to hide and sleep. Appropriate hide objects include a T-shirt, towel, hammock, or tent. Toys can offer great entertainment, but soft rubber or foam toys should be avoided as these objects are often the cause of foreign body obstruction. Polyvinyl chloride piping or cardboard tubes are great for play and exercise. Also, toys made of cloth, metal, hard plastic, or paper bags are safe for behavioral stimulation.

If ferrets are allowed to roam free in the house, the house should be ferret-proofed. This involves the obstruction of small places where they may escape, such as behind large appliances, inside of recliners, and within mattresses and furniture. These are often harmful places for ferrets where severe traumatic injuries may occur or soft foam might be ingested. Any other foam or rubber objects should be removed from the room as well. It is recommended that all free-roaming ferrets be supervised and suspect objects (e.g., recliners) inspected before use.

Nutrition

Ferrets are carnivorous and require a suitable diet. A diet that is high in good-quality animal protein and fat and low in complex carbohydrates and fiber is recommended. An adult, nonbreeding ferret has a dietary protein requirement of 30% to 40% and a fat requirement of 18% to 30%.³ High-quality kitten or commercially prepared ferret food can be offered in a dry pelleted ration. Commercial dog and cat food should be avoided, as these do not have adequate protein levels and often contain plant-based proteins. The ingestion of a diet consisting of plant proteins can result in urinary calculi (see Nutritional Disease). There are several good-quality, commercially prepared ferret diets available, such as Marshall Farms Premium Ferret Diet (Marshall Pet Products, Wolcott, NY), Totally Ferret (Performance Foods, Inc., Broomfield, CO), Mazuri Ferret Diet (Purina Mills, Inc., Richmond, IN, and Zupreem Premium Ferret Diet (Premium Nutritional Products, Inc., Mission, KS). Fat may be supplemented through the use of Linatone (Lambert Kay, Cranbury, NJ), a commercially available fatty acid supplement. Treats may consist of pieces of meat or meat baby food. The sick ferret can be supplemented with Prescription Diet Canine/Feline a/d (Hill’s Pet Products, Topeka, KS), Nutri-Cal (EVSCO Pharmaceuticals, Buena, NJ), or Glucerna (Abbott Laboratories, Columbus, OH), which are high-calorie, high-fat nutritional supplements. (See Therapeutics for further details on nutritional supplementation for the ill patient.) Ferrets that are prone to develop gastric hairballs can be given 1 to 2 ml of a cat laxatone 2 to 3 times a week as a prophylaxis. Water should always be made readily available. This can be accomplished via a heavy bowl or a sipper bottle. Fasting of ferrets for procedures requiring sedation or blood tests may be accomplished by withholding food for 4 to 6 hours. Extended fasts should be avoided, particularly in ferrets that have been diagnosed with insulinoma, to prevent severe hypoglycemia.

Routine Exams

Owners should be educated early on about ferret preventative health care. It begins at an early age before the ferret even leaves the breeding farm with its initial vaccinations. It then becomes the owner’s responsibility to complete the young ferret’s early preventative health care, which consists of vaccination, heartworm prevention, and parasitic identification and treatment. These early visits to the veterinary clinic are great opportunities for veterinarians to educate owners about proper diet and husbandry. Owners should be encouraged to return annually for routine exams and subsequent vaccinations. The routine exam also creates opportunities for grooming (e.g., nail trimming) and identification and scheduling of necessary dental care. As the ferret ages, routine examination and even blood work, such as a complete blood count (CBC) and serum biochemistry panel, become important for the early detection of common, age-related diseases (e.g., insulinoma).

Vaccination

Ferrets are routinely immunized against canine distemper virus (CDV) and rabies virus. Ferrets are quite susceptible to CDV and there is a 100% mortality rate in unvaccinated ferrets infected with CDV.^6,7 There is little information available regarding natural rabies infection in the ferret; however, experimental studies have shown ferrets to be susceptible to infection with the virus.^8,9 Therefore, it is recommended to immunize them against rabies, particularly in rabies-endemic areas. As in dogs and cats, vaccination in ferrets is initiated in the presence of maternal antibodies and carried out to 14 to 16 weeks of age when maternal antibodies have waned and the ferrets’ own immune system can be stimulated to develop protective antibodies. A recommended schedule for administration of the CDV vaccine is when the ferret is 6 to 8 weeks, 10 to 12 weeks, and 14 to 16 weeks of age; the rabies vaccine should be administered at the time of the last distemper vaccination. Thereafter, annual booster vaccines for CDV and rabies are recommended. The vaccines can be administered subcutaneously in the interscapular region of the body. Some municipalities have passed ordinances requiring intramuscular administration of the rabies vaccine.

A variety of CDV vaccines have been used in ferrets, including several types of modified-live virus vaccines and recombinant canary pox-vectored vaccines, but currently there are only two USDA-approved distemper vaccines for use in ferrets.^6–810 The first is a modified-live avian cell culture CDV vaccine, Fervac-D (United Vaccines, Inc., Madison, WI), and the other is a recombinant canary pox-vectored, subunit vaccine, Pure-vax (Merial, Duluth, GA). Canine combination vaccines or modified-live vaccines of ferret cell or low-passage canine cell origin should never be used in ferrets because of the occurrence of vaccine-induced distemper and death, particularly in sick or immunocompromised individuals.^6,8

An inactivated rabies vaccine, Imrab (Rhone Merieux Inc., Athens, GA), is licensed for use in ferrets. There are differing regulations on rabies vaccination in ferrets within city, state, and local governments, and it is advisable for the veterinarian to contact these agencies for the current policies. At this time, the American Veterinary Medical Association policy (Model Rabies Control Ordinance, http://www.avma.org/issues/policy/rabies_control.asp; March 17, 2006) for ferrets regarding vaccination, management of animals that have bitten humans, and exposure to rabid or suspect rabid animals is the same as that for dogs and cats.

Adverse reactions of the ferret to vaccination have been reported.^6,11,12 Anaphylactic reactions have been documented after ferrets received the Fervac-D vaccine and the Imrab vaccine, both in combination and alone.⁶ Most of the ferrets experiencing an anaphylactic reaction did so after receiving the CDV vaccine, although there have been reports of reactions occurring in animals after administration of the rabies vaccine alone.^6,12 Currently there are no published reports of anaphylactic reaction with the use of the Pure-vax vaccine; however, there are anecdotal reports of similar anaphylactic reactions occurring. The specific component of these vaccines or which vaccine should be implicated as the cause of anaphylactic reactions in ferrets is still unknown.

Anaphylactic reactions to vaccination generally develop within 30 minutes of the injection. Clinical signs associated with a reaction include vomiting, diarrhea, hematochezia, generalized hyperemia (most evident on the nose, mucous membranes, and footpads), hypersalivation, and fever.^6,8,12 Less commonly, respiratory distress can develop. Treatment for a vaccine reaction should consist of dexamethasone (2 mg/kg SC), diphenhydramine (1 mg/kg SC or 0.5 mg/kg PO), and epinephrine (0.1 ml of a 1 : 1000 solution SC).⁶ Supplemental oxygen should be administered as needed for dyspnea. Because anaphylactic reactions can persist for periods up to 24 to 48 hours, prolonged monitoring is recommended, with subsequent treatment with corticosteroids, antihistamines, or epinephrine as needed.¹² At the time of vaccination, owners should be advised to wait for 30 minutes after vaccination to monitor for the development of this type of reaction.

A recent report has suggested an association of the development of fibrosarcomas in ferrets with the vaccination site.¹¹ This is the first report of such an association in an animal other than the cat. Examination of fibrosarcomas that developed at the site of vaccination in ferrets revealed similar histologic, immunohistochemical, and ultrastructural characteristics to those reported in feline vaccine-associated sarcomas.

The projected benefits of vaccination must outweigh the adverse reactions in order for them to be considered a useful tool in preventative health care. As a whole, vaccination plays a vital role in reducing the level of infectious disease transmission in a population. However, due to the occurrence of adverse reactions, recommendations for vaccination must be made on an individual basis with the animal’s age, immune status, and current health status in mind. Ferrets that have exhibited previous vaccine reactions should either receive no further CDV vaccine or receive a dose of diphenhydramine 15 minutes before vaccination, although there have been variable results with the latter option. An effective alternative CDV vaccine, which has not yet been found to elicit anaphylactic reactions, is Galaxy-D (Schering-Plough Animal Health Co., Omaha, NE), a modified-live primate cell culture CDV vaccine.⁷ Duration of immunity induced by this vaccine in the ferret remains unknown, and use of Galaxy-D is extra-label in the ferret, requiring informed owner consent.

Quarantine

When a new ferret is brought into the household, a quarantine period is recommended before introducing it to other animals, particularly other ferrets. The purpose of the quarantine period is to identify and prevent transmission of infectious disease potentially carried by the new ferret. The duration of this period allows for the development of any clinical signs in a seemingly healthy ferret following entrance into the new household. Quarantine requires complete isolation of the ferret and its food, water, and cage supplies from other animals in the household for a period of at least 30 days. Proper hygiene such as hand washing, disinfection, and sanitation should be practiced during this period to avoid the transmission of any infectious organisms. The ferret also should receive physical and fecal examinations initially and vaccinations during quarantine. Should the new ferret exhibit any signs of sneezing, coughing, nasal or ocular discharge, fever, skin infection, diarrhea, or general unthriftiness, it should be brought to a veterinarian knowledgeable in ferret medicine immediately for a diagnostic work-up. In practice, these ferrets or any ferrets without a vaccination or medical history should be kept in strict isolation, as they can carry and transmit disease, such as canine distemper, to small animal patients. Precautions also should be made to prevent the transmission of any zoonotic disease from the ill ferret to the caretaker.

Disinfection

Routine disinfection in the veterinary clinic is important in preventing disease transmission and treating infection. Disinfection involves the killing of pathogenic microorganisms through physical or chemical means. Disinfectants are those chemical agents that are used on inanimate objects such as cages or feeding utensils, whereas antiseptics are those substances that may be used on living tissue for the treatment of open wounds or surgical scrub of the skin or mucous membranes. Sterilization is the complete removal of all living microorganisms from an object, an important application for instruments used for surgery or open wounds where there is a risk of infection. Techniques and agents should be chosen based on the nature and composition of the surface to be disinfected, the level of contamination and the degree of microbial killing desired, and the efficacy and safety of the disinfectant.¹³ Sterilization should be performed on all surgical instruments through physical (moist or dry heat) or chemical (glutaraldehyde, ethylene oxide, 58% hydrogen peroxide) means. When using a disinfectant, veterinarians should always follow the manufacturer’s recommendations on preparation and use to ensure efficacy and safety. Physical cleaning of any objects intended for disinfection improves the action of the disinfectant, as the killing power of disinfectants is significantly affected by the presence of organic matter. Antiseptics should be chosen based on their spectrum of action, residual effects, and tissue safety. Refer to Table 13-1 for information on commonly used antiseptics and disinfectants.

TABLE 13-1 Disinfectants and Antiseptics Commonly Used to Treat Ferrets and their Environment

Physical Restraint

Healthy ferrets are lively and active creatures, and it is not in their nature to remain still for any prolonged period of time. Therefore, restraint of the ferret patient, either manual or chemical, is often necessary in the veterinary clinic. Restraint is also indicated for those ferrets with a tendency to bite or nip, such as young ferrets or those infrequently handled. For simple procedures, such as physical examination, grooming, and occasionally venipuncture, manual restraint is sufficient. For other procedures, such as venous catheterization or radiographs, chemical restraint is usually required.

Ferrets can be gently grasped under the thorax, allowing the caudal part of the body to rest in the opposite hand or hang freely. Fairly tractable animals can be restrained against the exam table with one hand over the neck and shoulders and the other hand over the hindquarters. With the animal in such a position, eyes, ears, nose, and skin can easily be examined, and vaccinations can be administered. More controlled restraint involves scruffing, or the grasping of the excess skin on the back of the neck, and allowing the caudal half of the body to hang freely. This technique of restraint is great for abdominal palpation. Scruffing often elicits a characteristic yawn from the ferret, aiding examination of the oral cavity or administration of oral medications. Another form of manual restraint involves supporting the length of the ferret’s body along the handler’s forearm while pressing its body snugly against the handler’s body with the head of the ferret directed behind the handler’s body.⁴ This technique allows for easy administration of injections in the rear of the ferret’s body. Alternatively, feeding the ferret a small amount of Nutri-Cal during a procedure can distract the ferret patient, aiding in restraint.

Chemical Restraint

When physical restraint is not sufficient to safely control the ferret for procedures, chemical immobilization can be a safe alternative. A variety of injectable drugs have been used alone or in combination for restraint or prolonged anesthesia, including ketamine, xylazine, acepromazine, medetomidine, diazepam, and Telazol (tiletamine and zolazepam; Fort Dodge Animal Health, Ft. Dodge, IA) (Table 13-2). Yohimbine and atipamizole are typically used for the reversal of sedation induced by xylazine and medetomidine, respectively. Chemical immobilization using any of these drugs should be restricted to healthy ferrets and avoided in sick and debilitated animals. Additionally, the use of any of these drugs alone is better suited for restraint to perform noninvasive procedures such as blood collection, whereas the ketamine combinations may be adequate for minor surgical procedures.

TABLE 13-2 Dosages for Common Injectable Sedatives, Analgesics, Preanesthetics, Anesthetics, and Antagonists Used in Ferrets

A ketamine/xylazine combination provides acceptable analgesia, muscle relaxation, duration, and a smooth recovery.¹⁴ However, it is important to remember that this combination of drugs has been associated with cardiac arrhythmias and therefore should not be used in ferrets with cardiac disease. Use of the ketamine/xylazine combination also reduces certain hematologic parameters below baseline. The red blood cell count may be reduced by as much as 21%, hemoglobin concentration by 24%, hematocrit by 23%, and plasma protein by 15%. It has been suggested that these alterations may be due to sequestration of the blood in the spleen. Ketamine or Telazol may be used alone for restraint, but it is important to remember that these drugs may not lead to complete analgesia and muscle relaxation.¹⁵ Both of these drugs also result in hypersalivation; therefore, the use of an anticholinergic such as atropine is beneficial, particularly when these drugs are used as preanesthetic agents. A medetomidine/ketamine/butorphanol combination provides prolonged anesthetic periods with acceptable analgesia and may be effectively reversed with atipamizole.¹⁴

The ideal choice for chemical immobilization in ferrets is gas inhalants. The benefit of using gas inhalants, such as isoflurane or sevoflurane, is that they are safe enough to use in healthy or sick ferrets, and the availability of these gas inhalants in most practices makes immobilization by gas anesthesia a convenient choice. Ferrets may be masked down or induced in a clear gas chamber. When utilizing either of these inhalants, the depth of anesthesia can be quickly adjusted by altering the concentration of the inspired gas. Sevoflurane has shown to provide better systolic arterial pressures and a lower heart rate than isoflurane.¹⁴ Additionally, isoflurane can alter hematologic parameters by decreasing the hematocrit, hemoglobin concentration, and red blood cell count by 30% to 38%, and the plasma protein by 20% to 26%, likely by the same mechanism as the ketamine/xylazine combination. More detailed information on anesthesia of the ferret may be found in the Anesthesia section of the chapter.

Venipuncture and Hematologic Testing

Venipuncture is an important clinical technique that can be done with or without sedation. There are several sites for venipuncture that may be utilized depending on the volume of blood required for testing and the availability of assistants for restraint. Blood is assumed to be 5% to 7% of the ferret’s body weight, and 10% of the ferret’s blood volume may be safely withdrawn during a single collection.¹⁷ Diagnostic laboratories performing hematologic tests on ferrets typically require only 0.5 to 2 ml of blood, whereas larger quantities are needed from ferrets serving as blood donors.

Blood may be collected from the cephalic or lateral saphenous vein using a 25- or 26-gauge needle and 1-ml syringe when quantities of less than 1 ml of blood are required. Restraint for venipuncture of the cephalic vein is similar to that of the cat or dog, with the head of the ferret securely restrained with one hand by an assistant to prevent biting during the procedure. A towel may be wrapped several times around the body to provide additional restraint. When utilizing the lateral saphenous vein for venipuncture, an easy technique involves the use of a 25- or 26-gauge needle without an attached syringe, collecting blood drop by drop directly from the hub of the needle into capillary tubes. This is a good site when serial glucose measurements are necessary. Topical Emla cream (AstraZeneca Pharmaceuticals, Westborough, MA) can be applied on the skin over the vein to provide local anesthesia during the collection process.

Larger quantities of blood should be withdrawn from the jugular vein or anterior vena cava. Again, the ferret may be restrained like a cat for jugular venipuncture, with the forelegs pulled forward from the body and the head extended, nose pointed upward. The jugular veins of the ferret lie more laterally than the cat. Overextension of the head should be avoided as this can reduce jugular vein distention. Another technique for jugular venipuncture involves positioning the towel-wrapped ferret into dorsal recumbency with its head extended.¹⁴ While the ferret is distracted with Nutri-Cal, venipuncture can be performed using a 22- or 23-gauge needle bent at a 30-degree angle, attached to a 3-ml syringe. When collecting blood from the anterior vena cava, the veterinarian should consider sedating active ferrets with general anesthesia. This site should not be used in ferrets with bleedings disorders, because this vein is located within the thoracic cavity and does not allow for direct hemostasis by the clinician. With the ferret placed in dorsal recumbency, a 22- or 23-gauge needle, attached to a 1-to-6-ml syringe, is inserted at the junction of the first rib and the sternum (Figure 13-1). If you approach from the animal’s left side, the needle should be directed toward the right elbow. If you approach from the animal’s right side, the needle should be inserted parallel to the sternum. The anterior vena cava is superficial within the thoracic cavity and may often be located upon retraction of the needle. Always maintain a negative pressure draw, looking for a blood “flash” in the hub of the needle.

Figure 13-1 With the anesthetized ferret in dorsal recumbency, the anterior vena cava can safely be sampled.

Diagnostic laboratories usually establish reference ranges for the tests offered for ferrets. Reference ranges for the ferret CBC and serum chemistry panel may be found in Box 13-3 and Table 13-3, respectively. Hematologic parameters for the ferret are very similar to those of the cat; however, the erythrocyte, hematocrit, and reticulocyte counts are generally higher in the ferret.¹⁸ Ferrets also have a slower erythrocyte sedimentation rate; therefore, it is necessary to spin microhematocrit tubes for longer time periods than for dogs or cats. There is little information available on blood coagulation parameters in ferrets, although the prothrombin time has been reported to be 14.4 to 16.5 seconds.¹⁸ As with other animals, there is an age-related decrease in the enzyme alkaline phosphatase due to a reduction in the bone isozyme when rapid growth has ceased.¹⁸ Differential diagnoses for ferret patients that present with elevated liver enzymes include liver disease, exposure to ingested or environmental toxins, and Aleutian disease.¹⁹ Creatinine is normally cleared from the blood much faster in ferrets than other mammalian species; thus, any elevation in creatinine is significant and should be pursued further.²⁰

TABLE 13-3 Serum Biochemical Values for the Ferret^*

* Combined values for female ferrets and intact and castrated male ferrets are from Fox JG: Normal clinical and biologic parameters. In Fox JG, editor: Biology and Diseases of the Ferret, ed 2, Philadelphia, 1998, Lippincott Williams and Wilkins; Thornton PC, Wright PA, Sacra PJ et al: The ferret, Mustela putorius furo, as a new species in toxicology, Lab Anim 13 : 119-124, 1979; and Lee EJ, Moore WE, Fryer HC et al: Hematological and serum chemistry profiles of ferrets (Mustela putorius furo), Lab Anim 16 : 133-136, 1982.

Urine Collection and Urinalysis

Urinalysis is useful for identifying urinary tract disease in the ferret. Urine can be collected from a voided sample, urethral catheter, or cystocentesis. When evaluating voided or catheterized samples, bacterial contamination is a possible complicating factor to consider. Although sometimes necessary in the blocked patient, catheterization, particularly in male ferrets, can be difficult. Samples acquired via cystocentesis are preferred, and in obstructed ferrets, where catheterization cannot be achieved, cystocentesis is necessary for immediate relief of a significantly distended bladder. With the ferret under anesthesia and positioned in lateral or dorsal recumbency, the bladder should be isolated between your index finger and thumb and the sample collected using a 22- to 25-gauge needle fastened to a 3- to 6-ml syringe; this is similar to the technique used for dogs and cats. Metabolism cages may also be used to collect 24-hour urine samples.

Catheterization of the ferret usually requires general anesthesia. Sterile technique is recommended to prevent the iatrogenic introduction of contaminants into the urinary tract. Again, male ferrets can be difficult to catheterize; this is because of the acute angle at which the urethra turns at the ischial arch. The presence of a urethral stone or prostatomegaly may make the procedure impossible without causing additional trauma. Care should be taken to prevent iatrogenic perforation of the urethra when passing the catheter through this turn at the ischial arch. With the ferret placed in dorsal recumbency, the penis is extracted from the prepuce, initiating the catheterization process. Magnification may be necessary to visualize the urethral opening on the ventral aspect of the penis. A needle with the bevel filed off can be inserted into the opening to flush and distend the urethra with saline to facilitate the introduction of the catheter into the urethra. A water-soluble lubricant also makes passage of the catheter easier. A 20- to 22-gauge, 8-inch jugular catheter, a 3.5-Fr red rubber tube, or a 3.0-Fr Slippery Sam Tomcat urethral catheter (Cook Veterinary Products, Eight Mile Plains, Queensland, Australia) may be used.²¹ The latter option is preferred based on the size and rigidity of the catheter. An intravenous catheter stylet or sterile guitar string can be used to provide rigidity to the catheter; again, the veterinarian needs to be conscious not to traumatize the urethra during the passage of the catheter.²¹

Female catheterization is an easier technique. With the animal under general anesthesia, the female should be placed in ventral recumbency with the caudal body elevated. The urethral opening is located on the ventral floor of the vaginal vestibule, just cranial to the clitoral fossa. It may be visualized with an otoscope, endoscope, or a vaginal speculum. The catheter can be placed by sliding it along the ventral floor of the vagina, directed at an acute angle ventrally, until it enters the urethra.^21,22 Catheters that are placed for therapeutic purposes can be secured by suturing butterfly tape to the skin, and if necessary, catheters can be attached to a urine collection system. Ferrets should be closely monitored for entanglement of the tubing or disturbance of the catheter set.

Normal ferret urinalysis parameters can be found in Table 13-4. Protein is a common finding in ferrets, possibly due to high systolic pressure and thicker intrarenal arterial walls.¹⁸ With this finding, however, the clinician should include genitourinary infection and Aleutian disease as differential diagnoses. Blood in the urine may be the result of iatrogenic trauma to the urethra during catheterization, cystitis, urethritis in males, or estrus in females. False positives for ketonuria in male ferrets have been reported with the use of urinalysis strips. The similarity in color of the dark urine produced by male ferrets and the reagent test strip is a possible explanation of the ketonuria false positive result.¹⁷ Examination of urine sediment may reveal crystalluria in patients with blocked urethras or an accumulation of white blood cells in ferrets with urinary tract infection (Figure 13-2). An elevated urine pH has been associated with a diet high in plant proteins and is a good indication that diet correction may prevent crystalluria and subsequent urolithiasis.

TABLE 13-4 Normal Urinalysis Parameters for the Ferret

Figure 13-2 Struvite crystals are most commonly found in ferrets with crystalluria and can be identified easily with urine sedimentation. This finding is typically due to an improper diet containing high levels of plant-based proteins. A, Unstained (100). B, Unstained (400).

Fecal Examination

Although intestinal parasitism is relatively uncommon in captive ferrets, the examination of feces as a diagnostic tool should not be overlooked considering the susceptibility of the ferret to a variety of gastrointestinal (GI) disorders. Due to the short GI transit times and the habit of ferrets to defecate in the same location within their cages, acquisition of a sample is not difficult. Often, restraint in the exam room is enough to stimulate defecation by the ferret patient. The color, quantity, and consistency of the fecal sample should be described in the record, as this may change according to the disease process present (e.g., green, mucoid diarrhea associated with green slime disease). Fecal exams for parasite identification may be performed at the time of the annual exam using a direct smear and a fecal flotation technique with sodium nitrate or a sugar solution. Further discussion of internal parasitism can be found in the section on infectious diseases. Ferrets that present with diarrhea should also have a fecal Gram stain done to evaluate the sample for the presence of pathogenic microorganisms. If bacterial pathogens are suspected, a fecal culture should be pursued.

Diagnostic Imaging

Diagnostic imaging is very useful in the assessment of several disease processes in ferrets. Radiography is advantageous in the initial identification and assessment of common diseases, such as cardiac disease, splenomegaly, GI disease, urolithiasis, and prostatomegaly. Where questions may be left unanswered regarding GI disease through survey radiographs, the addition of contrast material becomes useful for the diagnosis of foreign body obstruction, bowel loop thickening, or even gastric ulceration. Ultrasonography has also proven useful in the further evaluation of certain disease processes such as cardiac disease, renal cysts, and adrenal gland disease.

Because radiographic techniques require an immobile patient, sedation is usually necessary. Ferrets’ long cylindric bodies can make proper positioning for radiography challenging, but extension of the forelimbs cranially alongside the head and the rear legs caudally facilitate this endeavor. They can then be secured in place with medical tape for film exposure. The entire body of most ferret patients can fit on a large cassette film, reducing the number of radiographs required for many examinations. The radiographic settings preferred for all full body ferret radiographs are 50 kVp, 100 mAs, and 1/10 sec time. For contrast radiography, 4 to 6 ml of barium is the recommended oral contrast dosage. If gastric ulcers or a bowel perforation is suspected, an iodine-based contrast is recommended. Ferrets have a rapid GI transit time; therefore, films should be taken every half-hour to gain a complete assessment of the GI tract.

Ultrasonography in the ferret follows the same principles applied to the cat and dog. Although ultrasonography does not require sedation, a technique of distraction (e.g., Nutri-Cal treat) usually reduces any active resistance. A higher frequency transducer, such as a 10- or 11-MHz transducer, is recommended to enhance the resolution of the image for the smaller ferret patient.²³