What is a Small Exotic Mammal?

Lofty topic, encompassing multiple orders. Here we will try to focus on the more unusual and yet more common small mammals, focusing on the following animals:

 Insectivora: hedgehogs

 Xenarthra: tamandua

 Carnivora: skunk, raccoon, coatimundis, kinkajou

 Rodentia: porcupines, chinchilla

Since there are such vast differences between the orders of mammals, we will focus on generalities of restraint, drawing blood, important anatomical features and diseases of concern. Of critical importance is knowledge of basic biology and having a good foundation in general veterinary medicine. When you know the normal habitat, diet and behavioral attributes of your patients, this goes a long way in identifying an abnormal state. If you can become a good animal biologist, then you will be a good exotic animal practitioner. There are a number of resources that you can utilize. Prior to seeing a particular animal, it is important to become educated on that species.

Legalities

It is recommended that you know the specific legal requirements for pet or wild animal ownership and the ability to treat these animals in your state. As a critical example are skunks; in some areas of the US, not only are they forbidden to be kept as pets, but are also not allowed to be treated. Vaccinations, particularly for rabies, may not be allowed. Regardless, it should be recognized that rabies vaccines are not approved for most small exotic mammals and thus, even if animals are vaccinated, pending state requirements, animals that bite might still be euthanized for rabies testing as there is no antemortem test that is accepted.

Specific Anatomical or Physiological Points of Some Species

 Chinchilla

 Prefer cool and dry conditions, heat stroke is a common problem.

 Jump and climb, require vertical space.

 Require dust baths for grooming.

 Fur slip (hair loss) can occur with rough handling or grasping after a fleeing animal. Don't shave them if you don't have to.

 No inguinal rings, thus special attention to closure for castrations.

 Hedgehog

 Roll into balls for defensive posture. Spines do not usually come out when handling.

 Kinkajou

 Frugivorous. Have normal hairless areas on face. Prehensile tails.

 Porcupine

 Some porcupine species have barbed quills. Others have skin that will tear with the slightest pressure, even when drawing blood. Hard to get suture through this skin, tissue glue is often best to appose.

 Raccoon/Coatimundi

 Strong and agile, moderate subcutaneous space, especially around neck, do not scruff. Raccoons are very smart, can open simple locks. No particular variation from a typical omnivore.

 Skunk

 Anal glands have a strong musk that can be ejected for a long distance (several meters). These glands can be removed via surgery.

 Tamandua

 Large claws on forelimbs which can be dangerous. Small mouth, difficult to examine. Intubation is not possible without a cut-down of the trachea.

Examination

Initial assessment should be made by observing the animal in its transport container. Once the animal is restrained by whatever method chosen, then a hands-on exam should be performed. Ocular exams may be difficult depending on the relative miosis of the pupils based either on species anatomy or anesthetic choice. An oral exam should always be performed with careful evaluation of the gingiva and firmness of the teeth within the sockets. Not all dental diseases are overt and loose teeth can be encountered without other signs. Lymph nodes should be examined. Secondary sex characteristics are very diverse and knowledge on a species basis is valuable. Anatomical placement of nipples is one example; for instance, porcupines will have their nipples in the lateral axillary region. Evaluation of skeletal structure and range of joint motion should be completed. Thoroughly examine the skin and digits/claws for abnormalities. Knowledge of glandular location and material that is exuded can be crucial (an aardwolf for instance has remarkable anal glands and glandular material that is both oddly orange colored and has a foul odor). Abdominal palpation is accomplished as with any other mammal. Body condition scores should be assessed and evaluated in concert with weights.

Fecal analysis should be part of a minimum database (MDB); where possible, urinalysis is done to complete the MDB.

Dental Formulas

Restraint

The most basic task is restraint of the small mammal. While manual restraint can be utilized, particularly for quick procedures such as minor treatments and assessments, the reality is that most veterinarians working with these animals sedate them for a good thorough exam both to reduce stress (the clinician's stress and the patient) as well as for safety purposes.

If manual restraint is necessary, then appropriate equipment must be on hand. Handling gloves should be used that don't restrict grip but can tolerate punctures from sharp teeth and claws. Depending on the size of the animal, you may need to consider long gloves. Variable nets should be available that have appropriately sized mesh and good tensile strength. A snare or 'rabies' pole is an important piece of equipment to have. Only experienced handlers should attempt to restraint some of the more agile and sizeable mammals.

In general, anesthetic induction with a chamber of most small mammals is a viable and safe method to anesthetize the animals. It can require a lot of gas and management of waste gasses is important. An appropriately sized chamber will provide rapid inductions. The larger the chamber, the longer it takes to fill with gas and the longer the induction. Wrapping an animal in a carrier with a plastic bag can work, but you have no waste gas options and visibility/accessibility is challenging. Having a chamber that allows you to manipulate size and space will provide the most flexibility. Either isoflurane or sevoflurane will work; however, the latter is less effective in the larger specimens and recoveries are occasionally unexpected although rapid. When injectable anesthesia is preferred, many options exist and should be researched prior to use.

Training is an excellent method for managing exotic mammals and basic operant conditioning methods can be utilized. A great opportunity for training is to desensitize animals to enter crates, squeeze cages, etc. for transport and to allow for sedation.

Once anesthetized, standard monitoring should be utilized. Hypothermia is a common consequence of sedation, thus using a warming system that won't damage the animal's skin is necessary. Conversely, some of these patients can damage the warming system (e.g., water beds and porcupines), thus care must be taken to avoid punctures. Hypothermia is relative and knowing basic body temperature is crucial, particularly with edentates and some insectivores.

Endotracheal intubation in some of the exotic mammals can be challenging at best and impossible in some. Carnivores usually pose no particular difficulty. The anteaters (tamandua) have a very small oral orifice in comparison to their tracheal size, thus intubation is not possible orally; however, a cut-down at the trachea may be utilized in an emergency. Blind intubation is often necessary in the rodent or rodent-like mammals. Specialized gags and laryngoscopes can be purchased to help facilitate intubation of these animals. Endoscopic assistance can be of great value as well.

Blood Collection

The rule of thumb for all mammals applies - 1% of body weight is safe in an otherwise healthy animal. The caveat to this is that hematoma formation in smaller mammals can result in significant blood loss, thus collecting the minimum amount required would be prudent.

General sites for venipuncture are similar to other animals: lateral saphenous and cephalic veins, ear veins, jugular veins, and femoral and tail vessels. Less used but available sites are the vena cava, the heart, and periorbital sinus in some species; these are usually reserved for samples that are critically needed.

Other Diagnostics

As with all other mammals, cytological analysis, imaging, endoscopy and necropsy can be worthwhile tools to utilize in a complete work-up for a disease issue.

Nutrition

This is a critical topic that is outside the scope of this document, the reader is referred to additional reference literature for species-specific nutritional topics.

Diseases

 Chinchilla: GI bloat and/or stasis, dermatomycosis, barbering, paraphimosis secondary to fur entrapment, fractures of the tibia and fibula

 Coatimundi: ocular trauma, bite wounds, diabetes, nutritionally induced kidney disease (high protein diet), dental disease, ear mites (Otodectes), foot trauma secondary to digging (natural behavior on unnatural surface)

 Hedgehog: dental disease, oral squamous cell carcinoma, obesity, dermatitis

 Kinkajou: blastomycosis, obesity, periodontal disease, cardiomyopathy

 Porcupine: trauma, dental disease

 Raccoon: distemper, parvovirus, dental disease (especially fractured canines), obesity, diabetes, ear mites (Otodectes), hyperthyroidism, polycystic kidney disease

 Skunk: obesity, amyloidosis, cardiomyopathy, dental disease

 Tamandua: diabetes, historic vitamin K deficiency issues, vertebral hyperostosis (probable hypervitaminosis A and/or D)

General

 Geriatric diseases: neoplasia, arthritis, dental loss, renal failure

 Diarrhea: run enteric pathogen culture screens. Note that Salmonella can be normal flora in some of these animals, therefore you must identify the serovar to determine pathogenicity

Therapeutics

In general there is a lack of pharmacokinetic data for many exotic mammals. As such, we rely on extrapolation to the closest taxonomically related animal. There are references available for exotic mammals, which are sometimes based on testing trials, but mostly they are anecdotal accounts where either a clinical impression is offered or at the very least, the consequences (or importantly, lack of consequences) of drug administration are recorded.

Vaccination

The practice of vaccination should depend on species predilection for disease or public safety. Most vaccines are not approved for use in these species but are nonetheless used empirically. Caution must be exercised as many of the species have exhibited vaccine-induced disease, thus killed or modified-live vaccines are recommended.

Zoonotic Diseases

Ringworm, giardiasis, Campylobacter spp., Pasteurella spp., cryptosporidiosis, Toxoplasma gondii, Baylisascaris procyonis, and Sarcoptes scabiei (most animals have their own subspecies and are not likely zoonotic) among others. It is prudent to practice proper hygiene and protective gear to prevent these diseases in your practice. More importantly, you should know them and counsel your clients how to avoid contracting these diseases from their pets.

Periodicals of Interest

1.  Exotic DVM magazine. 2324 South Congress Ave, Ste 2A. West Palm Beach, FL 33406.

2.  Journal of Exotic Pet Medicine (formerly Seminars in Avian and Exotic Pet Medicine). Elsevier/Saunders. St. Louis, MO.

3.  Veterinary Clinics of North America: Exotic Animal Practice. Elsevier/Saunders. St. Louis, MO.

References

1.  Brown SA, Rosenthal KL. Self-Assessment Color Review of Small Mammals. Ames, IA: Iowa State University Press; 1997.

2.  Carpenter JW. Exotic Animal Formulary. 4th ed. St. Louis, MO: Elsevier/Saunders; 2012.

3.  Fowler ME. Restraint and Handling of Wild and Domestic Animals. St. Louis, MO: WB. Saunders Co.; 2008.

4.  Fowler ME, Miller RE, eds. Zoo & Wild Animal Medicine. 5th ed. St. Louis, MO: WB. Saunders Co.; 2003.

5.  Mitchell M, Tully TN, eds. Manual of Exotic Pet Practice. St. Louis, MO: Elsevier/Saunders; 2008.

6.  Quesenberry KE, Carpenter JW, eds. Ferrets, Rabbits and Rodents: Clinical Medicine and Surgery. 2nd edit. St. Louis, MO: WB. Saunders Co.; 2004.

7.  West G, Heard D, Caulkett N, eds. Zoo Animal and Wildlife Immobilization and Anesthesia. Ames, IA: Wiley-Blackwell; 2006.