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Authors: Joerg Mayer, D.V.M., Gretchen Kaufman, DVM
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OCW Zoological Medicine 2008
Exotic Small Mammal Medicine (2009)
J. Mayer, DVM / G. Kaufman, DVM
Cummings School of Veterinary Medicine at Tufts University

1. Learning Objectives

This chapter will review the most common health issues associated with exotic small mammal companion animal species. In addition to the list below, color coded topics indicate the learning objectives that the student should become familiar with. Cases will be presented in class to illustrate these topics. Students should focus on the following:

  • Understand the management of dental malocclusion in the guinea pig and chinchilla

  • Know the importance of closing the inguinal ring in surgical castration of the male guinea pig and chinchilla

  • Know the antibiotics that are safe to use in the guinea pig, chinchilla, and hamster and why this is an important issue

  • Be familiar with the following diseases in the guinea pig

    • Vitamin C deficiency

    • Dystocia

    • Lymphadenitis

  • Be familiar with the following diseases of the pet rat

    • Mycoplasma

    • Mammary tumors

    • Chronic progressive nephropathy

    • Obesity

  • Be familiar with the zoonotic diseases associated with rodents

  • Gain an appreciation for the husbandry and health challenges associated with keeping unusual exotic mammal species such as hedgehogs and sugar gliders as pets.

1.1. Review and Resources

Please review relevant material from 1st year Comparative anatomy before attending these lectures. Additional material can be found in

  • A Colour Atlas of the Anatomy of Small Laboratory Animals: Rabbit Guinea Pig by Peter Popesko, et al. available in the Wildlife Library (not for circulation).

The ICE First Step Program on Exotic Small Mammal Medicine, developed by Theresa Lightfoot, is a great supplement to this syllabus.

1.2. 'Pocket Pets?'

A quote from David L. Graham, D.V.M. PhD.

"Now, ponder, please that thought of the Bard's 'what's in a name?' Like, for example, 'Pocket Pets'? In my humble opinion all veterinarians should abjure use of the term 'pocket pets. It is (at least to me and few colleagues) offensive and denigrating to the inherent uniqueness and dignity of those creatures that happen to be of such small size that they can fit into a pocket. The term suggests that such pets can be maintained in a more casual and less careful, less caring, and less thoughtful manner than is required for maintenance of other, more traditional companion animal species. Such creatures are of no lesser biological and moral consequence than are larger, more traditional pets. I'm sure that the cute alliteration of the term is a major reason for its acceptance, but I urge that some other rubric(s) be coined under which to group these relatively diminutive companion animals. Please, they are sugar gliders, gerbils, hedgehogs, mice ('wee sleekit beasties' - R. Burns), small pets, little small animals (to differentiate them from dogs and cats which are merely 'small animals'), minipets ...but please...not 'pocket pets.'"

References and Resources

Conservation Medicine Challenges

Supplemental Readings

1, 2, 3

2. Rodents - Introduction

2.1. Taxonomy (abbreviated list)

Order Rodentia

Suborder Sciurognathi

Family Sciuridae

squirrels, marmots, chipmunks, gophers, beavers, kangaroo rats, springhaas

Family Muridae

rats, mice, hamsters, lemmings, voles

Suborder Hystricognathi

porcupines, cavies (guinea pigs), capybaras, chinchilllas, agoutis

See also http://animaldiversity.ummz.umich.edu/site/accounts/classification/Rodentia.html#Rodentia

Free-ranging rodents are distributed worldwide and act as important members of the food chain. They also often act as vectors of disease.

Porcupine
Porcupine

Rodents seen most often in captive settings include:

  • Zoos - capybara, Patagonian cavy, agouti, prairie dogs, kangaroo rat, etc. guinea pigs, pacas (aguoti paca), hutias, tree porcupine, porcupines, woodchucks, naked mole-rats, degus, etc.

  • Pets - Norway rats, mice, guinea pigs, chinchillas, hamsters, gerbils, degus, prairie dogs

  • Research Laboratory - Norway rat (varieties), mice, guinea pigs, hamsters, etc.

Critically Endangered RODENTS from IUCN http://www.redlist.org/

Acomys cilicicus

Gerbillus dalloni

Leptomys elegans

Oryzomys gorgasi

Allactaga firouz

Gerbillus floweri

Leptomys signatus

Pappogeomys neglectus

Namdapha flying squirrel

Gerbillus grobbeni

Macrotarsomys ingens

White-eared pocket mouse

Short-tailed chinchilla

Gerbillus hoogstraali

Lesser small-toothed rat

Pacific pocket mouse

Mt. Isarog striped rat

Gerbillus lowei

Makalata occasius

Perdido Key beach mouse

Crateromys paulus

Gerbillus mauritaniae

Mallomys gunung

Peromyscus pseudocrinitus

Crunomys fallax

Gerbillus occiduus

Melomys rubicola

Peromyscus slevini

Dendromus vernayi

Gerbillus quadrimaculatus

Meriones chengi

Pogonomelomys bruijni

Dicrostonyx vinogradovi

Gerbillus syrticus

Cabrera's hutia

Pseudohydromys murinus

Morro Bay kangaroo rat

Heteromys nelsoni

Large-eared hutia

Alice Springs mouse

Giant kangaroo rat

Hylopetes winstoni

Dwarf hutia

Pseudomys glaucus

Dipodomys insularis

Isolobodon portoricensis

Little earth hutia

Rattus enganus

Dipodomys margaritae

MacDonnel range rock-rat

Microtus evoronensis

Rattus montanus

Fresno kangaroo rat

Northern Idaho ground squirrel

Microtus mujanensis

Rhagomys rufescens

Tipton kangaroo rat

New Mexico least chipmunk

Mus kasaicus

Sicista armenica

Gerbillus principulus

Hidden Forest chipmunk

Garrido's hutia

Sigmodontomys aphrastus

Eliurus penicillatus

Mount Graham red squirrel

Nectomys parvipes

Tokudaia muenninki

Gerbillus bilensis

Cathlamet pocket gopher

Orthogeomys cuniculus

Tylomys bullaris

Gerbillus burtoni

Zyzomys palatilis

Oryzomys galapagoensis

Tylomys tumbalensis

Gerbillus cosensis

Leimacomys buettneri

-

Typhlomys chapensis

2.2. Anatomical/Physiological features of note

  • Teeth

    • Rodents have open rooted incisors which are continually growing

    • Cavies, chinchillas, capybara also have open rooted molars

    • Sciuridae (squirrels), new world porcupines, rats and mice have closed molars (i.e. less likely to see molar malocclusion clinically)

  • Many rodents engage in coprophagy for dietary reasons

  • Select species of rodents hibernate

2.3. General Health Issues

2.3.1. Non-infectious diseases

  • Dental disease/malocclusion is seen especially in species with open rooted teeth

  • Woodchucks are reported to experience vascular dieseases of various types - arteriosclerosis, aortic rupture, cardiovascular and cerebrovascular disease etc.

  • Hypervitaminosis D is commonly reported in captive beaver, woodchucks, pacas and agoutis that are fed monkey chow

  • Urinary tract disease is reported in many rodents and includes

    • calculi

    • chronic interstitial nephritis

    • chronic progressive nephrosis (rats)

    • amyloidosis

    • nephrotic syndrome

    • urinary tract infections

  • Diabetes is seen in degus, ground squirrels, sand rats, spiny mice, chinese hamsters

2.3.2. Infectious diseases

  • Rabies is rarely reported, but possible (keep in mind ANY mammal can be infected with this virus!!)

    • Rabies virus infection in a pet guinea pig and seven pet rabbits. Eidson M, Matthews SD, Willsey AL, Cherry B, Rudd RJ, Trimarchi CV. J Am Vet Med Assoc. 2005 Sep 15;227(6):932-5, 918.

    • Rabies in two privately owned domestic rabbits. Karp BE, Ball NE, Scott CR, Walcoff JB. J Am Vet Med Assoc. 1999 Dec 15;215(12):1824-7, 1806.

    • Woodchuck is most commonly reported rodent in New England

    • A squirrel was found positive in 2004 in MA

    • It's assumed that most rodents die from the bite (exposure) before signs of rabies develop, or positive animals are rarely encountered (and thus reported) by humans

  • Hantavirus reservoirs

  • Encephalomyocarditis virus (rat as reservoir?)

  • Parvovirus reported in porcupines

  • Squirrel fibromatosis – pox virus in gray squirrels (Conservation dilemma in the UK: ProMEDmail 200550616.1693. http://www.promedmail.org)

  • Viral induced hepatitis/hepatocellular carcinoma - seen in captive woodchucks

  • Leptospirosis reservoirs (cotton rats, coypus, beavers, muskrats, woodchucks, voles, P. cavies, squirrels, deer mice), does not produce disease in the rodent but act as vectors for spread of the organism

  • Borreliosis reservoirs (mice)

  • Pseudotuberculosis Y. pseudotuberculosis, Y. enterocolitica (chinchillas, agoutis, beavers, lemmings, voles, mice, muskrats, coypus, prairie dogs, ground squirrels)

  • Yersinia pestis or plague (prairie dogs )

  • Tyzzers ds. occurs in many rodents

  • Fungal dermatitis

  • Aspergillosis (capybaras)

  • Parasites - variety of mites, tick, fleas, lice and fly larvae (myiasis, cuterebra), variety of helminths common, protozoa usually without disease, coccidia most likely to cause disease.

chipmunk
chipmunk

3. Guinea Pigs

Guinea Pig
Guinea Pig

Cavia porcellus

The guinea pig is an herbivorous rodent originating in South America. It was domesticated as early as 1000 BC.

Guinea pigs are still raised for food in South America, and used as pets and research animals around the world. A good resource on this topic is the book The Guinea Pig: Healing, Food, and Ritual in the Andes by Edmundo Morales and can be found at : http://www.amazon.com/Guinea-Pig-Healing-Ritual-Andes/dp/0816515581

3.1. Basic physiologic and anatomic parameters

LIFE SPAN

4-8 yrs.

HEART RATE

230 - 380 bpm

RESP RATE

42 - 104 bpm

RECTAL TEMP.

98.8 - 103.1 (F)

SEXUAL MATURITY

3 mo.(M), 2 mo.(F)

Guinea pigs have classic rodent dentition with two upper and lower incisors designed for gnawing and 1 premolar and 3 molar teeth on either side of the maxilla and mandible designed for grinding rough vegetation. All teeth are open rooted. Guinea pigs are monogastric hindgut fermenters like the rabbit.

  • Incisors 1/1

  • Canines 0/0

  • Premolars 1/1

  • Molars 3/3

Anatomic and physiologic peculiarities include:

  • no tail

  • only 2 inguinal nipples

  • large adrenal glands

  • very large vesicular accessory sex glands in the male

  • large open inguinal ring (testes can be completely retracted into abdominal cavity)

  • Kurloff bodies seen in some leucocytes on CBC

  • extended gestation period (59-72 days)

  • precocial young

  • yeast is normal GI flora (as is for rabbits)

Blood smear
Blood smear

3.2. Special considerations for husbandry and nutrition

Guinea pigs are easy to care for. They can be kept in open cages since they are poor climbers, but they can be good jumpers (esp. when scared). However they are the only mammal which will readily walk off the exam table, so never leave a guinea pig unattended on your exam room table.

Appropriate bedding materials are paper towels, plain newspaper or shredded paper. The more appealing cedar shavings should never be used for small animal bedding due to the potential hepatotoxicity from the phenol compounds in the shavings. Pine shavings have also been associated with increased respiratory disease and should be avoided if possible. Bedding must be changed frequently since urine buildup may produce ammonia toxicity with resultant increased susceptibility to respiratory infections or contribute to pododermatitis.

Guinea pigs are normally fed a diet including fresh good quality hay, Guinea pig pellets and fresh fruits and vegetables. Guinea pigs have an absolute dietary vitamin C requirement. Like some other New World animal species they are unable to make vitamin C. A deficiency will result in scurvy and eventual death from secondary complications.

Indoor setup for guinea pigs
Indoor setup for guinea pigs

Outdoor setup for guinea pigs
Outdoor setup for guinea pigs

(See Appropriate Care: A Basic Right for Guinea Pigs by Ruth Morgenegg, TB-Verlag, 2009, ISBN 978-3-9522661-3-7 and Appropriate Care: A Basic Right for All Rabbits by Ruth Morgenegg, TB-Verlag, 2009, ISBN 978-3-9522661-2-0 for additional information.)

Clinical signs of scurvy include a poor hair coat, anorexia, gingivitis, generalized pain, arthropathy especially at costochondral junctions, diarrhea, and respiratory infections. Vitamin C is normally added to all good quality guinea pig diets (pellets). Some owners will also supplement their pigs with fresh citrus fruit daily, or give OTC vitamin C supplements. Pelleted diets must be stored adequately (dry and cool, 22ºC, 72ºF) to preserve the vitamin content. 3 months after the date of manufacture, the vitamin C content cannot be guaranteed. Often times, the date of manufacture and the storage history prior to purchase of the pellets is unknown, allowing for problems to arise. Always supplement with vitamin C for any disease condition. Subclinical deficiency likely contributes to many disease states. Guinea pigs should not be fed rabbit pellets longterm because they do not have vitamin C added. Vitamin C administration in the drinking water is generally not recommended as this can change the taste of the water which will result in the animal not drinking. Direct supplementation via the food (as treat or supplement) is best.

Note that pathological conditions of an over supplementation of vitamin C have been published (see Kraus VB below).

Vitamin C Supplementation in the Guinea Pig

800 mg/kg of pelleted diet (milled)

OR

20 - 50 mg/guinea pig/day

3.3. Basic diagnostic approaches

  • Blood collection in the guinea pig can be performed at various sites including the jugular (difficult), pre-caval vein (preferred at TCSVM Exotic Service), lateral saphenous vein and the cephalic vein.

  • Radiographs should not be performed with manual restraint only. Light sedation (see formulary) or full anesthesia is needed in order to take appropriate radiographs to be able to evaluate the full body (teeth to bladder).

  • Ketamine and diazepam or midazolam work well for sedation. Facemask induction with isoflurane or sevoflurane works very well and recovery is fast and smooth.

  • Oral examinations (malocclusion) may initially be performed with a nose speculum, but a complete examination must be performed under complete anesthesia.

3.4. Basic therapeutic approaches

Guinea pigs are even more sensitive and susceptible to antibiotic induced enterotoxemia than rabbits. Great care must be taken to choose appropriate antibiotics and use them only when necessary. The drugs listed as "safe" for rabbits are also safe in the guinea pig with the exception of injectable Pen G procaine (this drug can be fatal even as a s.c. injection). Guinea pigs are often infected with Gram (+) infections and selection of antibiotics should take this into account.

Oral medication is commonly prescribed for home use and is easy for the owner to administer (antibiotic precautions hold especially for oral meds). IM, SQ administration is similar to rabbits and other small mammals. IV access is challenging utilizing the saphenous or cephalic sites. IO catheters should be considered when appropriate.

Injectable vitamin C can be given to guinea pigs in the hospital setting. Vitamin C supplementation is recommended for all disease states to eliminate the possibility of subclinical deficiency.

3.5. Common problems/diseases

In the Guinea pig, noninfectious disease presentations are usually more common than infectious disease processes as a primary problem.

  • Scurvy (see above)

  • Cystic calculi/urolithiasis

    • Calcium usually involved

    • Surgical removal of urinary calculi not uncommon

  • Diabetes - similar to adult onset diabetes in humans

Gastrointestinal disorders

  • Molar malocclusion "slobbers"

    • Very common in chinchillas and guinea pigs

    • Most likely genetic or dietary cause (type of roughage being offered)

    • Clinical signs - anorexia, weight loss, appearing hungry but dropping food, salivation causing a moist chin (slobbers)

    • Tongue (lower arcade) or cheek (upper arcade) lacerations causing pain

    • Requires examination and regular trimming under general anesthesia (see end of chapter for special dental instrument pack) ; use of a dental bur is best method

Slobbers in a guinea pig
Slobbers in a guinea pig

Guinea pig
Guinea pig

  • Hepatic lipidosis due to fasting (often the onset of this metabolic problem arises within 24 hours)

  • Gastrointestinal ileus

    • Following fasting or anorexia

    • Following GI surgery

    • Challenging to return motility

    • Aggressive pain management is indicated in these cases

  • Cloacal impactions

  • Diarrhea (dietary, parasitic, bacterial)

    • Early dx. and aggressive supportive care needed

    • Life threatening enterotoxemia

Reproductive disorders

  • Dystocia

    • Ideally should breed before 7 mos. of age

    • Pubic symphysis calcifies after this age and large offspring cannot fit

    • may present as surgical emergency, however many older pigs readily give birth without complications, so rushing to a caesarean section is not necessarily indicated

    • if the time period between the delivery of 2 piglets is longer than 30 minutes a dystocia is most likely occurring

  • Pregnancy toxemia (relationship to obesity, fatty liver)

  • Cystic ovaries very common in older (>3 year old) females

Guinea pig
Guinea pig

Inguinal herniation following dystocia in a guinea pig

Dermatitis

  • Fungal (ringworm, yeast)

    • Trichophyton mentagrophytes

    • Microsporum canis

  • Mites

    • Cheyletiella

    • Trixacarus cavaie

    • Treat with Ivermectin

  • Lice

  • Fleas

  • Severe ectoparasitism can manifest in “seizure like episodes. Every guinea pig with CNS signs should be screened and treated for ectoparasites

  • Barbering

  • Pododermatitis

Acariasis
Acariasis

Viral diseases

  • Adenovirus

  • Cytomegalovirus (Herpes)

  • Lymphocytic choriomeningitis virus (LCM) - Guinea pigs not reported to transmit to people (see other rodents)

  • Parainfluenza virus

  • Retrovirus

Bacterial diseases

  • "Lumps" cervical lymphadenopathy (Streptococcus zooepidemicus, Streptobacillus moniliformis)

  • Pneumonia and rhinitis (Bordatella bronchiseptica, Streptococcus pneumoniae, others)

  • Conjunctivitis (above pathogens and Chlamydophila caviae)

  • Enterotoxemia

  • Tyzzer's disease

  • Pododermititis

Parasitic diseases

  • Ectoparasites (above)

  • Eimeria caviae

  • Cryptosporidium wrairi

  • Balisascaris procyonis

  • Encephalitozoon

Neoplastic diseases

  • Benign skin tumors

  • Fibrosarcoma

  • Lipomas

  • Mammary fibroadenoma or adenocarcinoma (common in the male guinea pig)

  • Leukemia/lymphosarcoma

3.6. Surgery and Anesthesia

In general guinea pigs make poor surgical candidates and anesthetic complications are common.

Sedation is often used for restraint or minor procedures in the guinea pig. Injectable anesthetics such as Ketamine, diazepam, xylazine are very effective. Major surgical procedures should be performed under inhalation anesthesia. Intubation is difficult in the guinea pig, except in the hands of experienced personnel. Therefore it is not recommended for the occasional surgery. In general, guinea pigs do very well with mask administration of isoflurane. Procedures such as neutering, caesarian section, tumor removal, etc. are usually safely carried out with mask anesthesia. An intravenous or intraosseous catheter and fluid support is highly recommended. Catheters can be placed in the saphenous or cephalic veins. Subcuticular closures without external skin sutures are recommended since guinea pigs like to chew their incisions.

Anesthesia
Anesthesia

Neutering is occasionally performed for birth control reasons. The inguinal ring in the guinea pig is very large. An open castration must include closure of the inguinal ring. A closed technique does not require the manipulation of the inguinal canal. Dystocias may also involve herniation into the inguinal ring. Caesarian section is probably the most common cause for emergency surgery in the guinea pig.

Gastrointestinal surgery is sometimes required for removal of foreign bodies such as trichobezoars. An enterotomy carries with it a very poor prognosis. The gut of the guinea pig does not tolerate much invasion and usually responds with an intractable ileus.

4. Chinchillas

4.1. Basic physiologic and anatomic parameters

Chinchilla
Chinchilla

The chinchilla is closely related to the Guinea Pig. They differ in that they are generally smaller in size, have a long furry tail, and live a lot longer. They were bred for their wonderful soft coats for the fur coat industry, but have since become very popular pets. All chinchillas in the US originated from a breeding colony of only 9 animals! They are currently protected as wild animals in their natural range in the Andes mountains.

LIFE SPAN

8-20 yrs.

HEART RATE

180 - 380 bpm

RESP RATE

N/A

RECTAL TEMP.

96.8 - 100 (F)

36-38 (C)

SEXUAL MATURITY

3 mo.

  • Chinchillas have an even longer gestation period than the guinea pig (111-128 days)

  • Very precocial young

  • They are nocturnal and like to burrow during the day.

  • They are very intolerant of hot weather (dangerous if ambient temperature is above 85 F or 30C).

4.2. Special considerations for husbandry and nutrition

Chinchillas are generally kept caged in a large enclosure in the house. They are very attracted to chewing electric cords and should not be left out unsupervised. They should have a place to burrow or hide in the cage. Unlike the guinea pig, chinchillas can jump and climb fairly well. Chinchillas must have a dust bath, preferably daily but limited to about 20 minutes. This consists of a bowl with a special mixture of silver sand and Fuller's earth (available at pet stores). The dust bath can be withheld or limited in situations with open wounds or conjunctivitis, etc. Prolonged exposure or ad lib exposure can result in problems such as conjunctivitis.

The chinchilla is normally fed chinchilla pellets, hay and a variety of fresh greens, nuts and fruits. They can also be fed rabbit pellets since they do not have a special requirement for Vitamin C. A 'poor' quality hay appears to be best for these animals as they need to chew fibers which are high in crude fiber and often highly lignified.

4.3. Basic diagnostic approaches

  • Venipuncture sites are as in the guinea pig.

  • Radiology is also very similar to the guinea pig.

  • Normal blood values are listed at the end of this chapter.

Blood sampling
Blood sampling

4.4. Basic therapeutic approaches

Chinchillas also have a very sensitive GI flora and are susceptible to enterotoxemia. They also suffer from Gram (+) infections. The same medications recommended for the rabbit and the guinea pig are recommended for the chinchilla.

4.5. Common problems/diseases

Slobbers
Slobbers

  • "Slobbers" molar malocclusion (more common than in the guinea pig)

  • Heat stroke (optimal ambient temperature 65-80ºF)

  • Electrocution

  • Thiamine deficiency (neurologic)

Dermatitis

  • Barbering

  • Fungal (Trichopyton mentagrophytes), yeast

  • Fur mites

  • Fur slip

Gastrointestinal disorders

  • Intestinal ileus

  • Constipation (dehydration)

  • Trichobezoar (hairball)

  • Intussusception

  • Mucoid enteritis, enterotoxemia

  • Bacterial enteritis

  • Protozoal enteritis (Giardia)

Bacterial disorders

  • Pneumonia

  • Salmonella enteritis

  • Listeria enteritis and encephalitis

  • Yersinia pseudotuberculosis (diarrhea, encephalitis)

  • Abscesses following fighting

Parasitic disorders

  • Ectoparasites (above)

  • Giardia

  • Cryptosporidia

  • Balisascaris procyonis

5. Hamsters

  • Syrian (golden) Mesocricetus auratus

  • Chinese (Siberian) Cricetus griseus

  • Armenian

  • European

  • Teddy Bear

Hamster
Hamster

Hamsters should be kept alone. Fighting is common. They are nocturnal and will hibernate at temperatures below 41ºF. They possess large bilateral flank scent glands that can become impacted. They are used extensively in research due to their immune system peculiarities (cheek pouches).

5.1. Common problems and diseases

  • Ammonia toxicity (poor cage hygiene), and phenol toxicity (cedar shavings)

  • Enterotoxemia :

    • most acutely sensitive of the rodents

    • Use only SAFE antibiotics as listed for rabbits and guinea pigs

  • Proliferative ileitis "wet tail" (Lawsonia intracellularis), often with prolapse

    • Aggressive supportive therapy (fluids)

    • Antibiotics (Enrofloxacin and Tetracyclines)

  • Tyzzer's disease (Cl. piliformes) - rare

  • Diabetes mellitus (hereditary)

  • Renal amyloidosis

  • Urolithiasis

  • Neoplasia, impaction of the flank glands

  • Lymphocytic choriomeningitis virus (LCM) ZOONOTIC mice are natural host

  • Tapeworms (hymenolepis nana) ZOONOTIC

  • Demodex

  • Lymphosarcoma - very common

  • Adrenocortical adenomas (Cushings, hairloss)

    • Lysodren therapy

    • Poor prognosis

  • Malnutrition (low protein) induced hairloss

  • Staph pyoderma

6. Gerbils

Gerbils are generally less aggressive and more compatible then hamsters. They are still best kept alone. They are hardier than hamsters. Gerbils have tails.

6.1. Common problems and diseases

  • Tyzzer's disease

  • Salmonellosis

  • Hymenolepis nana tapeworms

  • Demodex

  • Cystic ovaries

  • Multiple tumors (> 2years of age)

  • Hereditary epilepsy, precipitated by stress

7. Rats & Mice

7.1. Rats

Rattus norvegicus - laboratory rat (albino), hooded rat ("Long Evans stock") ... many strains!!

Pet rat
Pet rat

Rats are a surprisingly good companion animal: intelligent and responsive. However they have a short life span ( 2-3 years). Rats are omnivorous and have a tendency for obesity. Chromodacryorrhea can be very pronounced in the rat (red porphyrins in the urine and other glandular secretions such as tears and nasal discharge).

7.1.1. Common problems and diseases

  • Mycoplasma - pneumonia, reproductive disease, arthritis, encephalitis

  • Tyzzer's disease

  • Subcutaneous abscesses

  • Staph pyoderma

  • Ringworm - trichophyton spp.

  • Ammonia toxicity

  • Self-mutilation

  • Chronic progressive nephropathy (old age disease)

  • Obesity

Viral diseases

  • Parvovirus

  • Sialodacryoadenitis virus (coronavirus) - respiratory

  • Sendai virus (PI I virus, more important in mice) - respiratory

  • Bunya virus - Hanta virus

Parasitic diseases

  • Pinworms Syphacia muris

  • Aspicularis teraptera, another oxyurid

  • Tapeworms - Taenia taeniaformis (intermediate host for cat)

  • Hymenolepis nana ZOONOTIC

  • Mites (several species)

  • Fleas

Rat Meds
Rat Meds

Neoplasia

  • Mammary fibroadenoma

    • Both males and females

    • Grow rapidly!

    • Easily resected, but will recur if animal is not spayed (estrogen dependant tumor)

  • Mammary adenocarcinoma

  • Squamous cell carcinoma

  • Pituitary adenoma - very common

  • Uterine, ovarian and vaginal carcinomas

  • MANY strain specific tumors

Mammary tumor
Mammary tumor

7.2. Mice

Mice are rarely seen in small animal practice. They are extensively used in research and well understood from a laboratory animal perspective.

Scabies in pet mouse
Scabies in pet mouse

7.2.1. Common problems and diseases

  • Barbering

  • Neoplasia (variety)

Bacterial diseases

  • Tyzzer's disease (first described in mice!) - death, diarrhea

  • Salmonella

  • Streptococcus - respiratory

  • Mycoplasma - respiratory, encephalitis

Viral diseases

  • Mousepox

  • Cytomegalovirus (worse for young)

  • Lymphocytic choriomeningitis virus (arenavirus) - ZOONOTIC, neurologic, sudden death

  • Sendai virus - respiratory

  • Pneumonia virus of mice (Paramyxovirus)

  • MANY other viruses of importance to lab animal medicine

Parasitic diseases

  • Toxoplasmosis (intermediate host)

  • Pinworms Syphacia obvelata

  • Aspicularis teraptera, another oxyurid

  • Tapeworms - Taenia taeniaformis (intermediate host for cat)

  • Hymenolepis nana ZOONOTIC

  • Mites (several species)

  • Ringworm

8. Prairie Dogs

8.1. Basic data

  • Rodents in the Sciuridae family

  • Ethical issues surrounding management of wild populations and taking for pets

  • Not legal as pets in MA!

  • Legal in many states to take from wild; large export market to Japan

  • Black tailed prairie dog (Cynomys ludovicianus) being considered for protection

  • Utah prairie dog (Cynomys parvidens) listed as threatened

  • Mexican prairie dog (Cynomys mexicanus) listed as endangered

  • Dangers of Yersinia pestis

8.2. Care and husbandry tips

  • Do not keep in wire cages - dental injuries

  • Main diet of rodent block, grass hay

  • AVOID dog food or monkey chow, excessive Vitamin D

8.3. Health issues

  • Odontoma - very common cause of respiratory difficulties

  • Ectoparasites, fleas

  • Ringworm

  • Pasteurella abscesses

  • Pododermatitis

  • Yersinia pestis plague, high mortality, ZOONOTIC

  • Other zoonoses: Tuleremia, Monkey Pox

  • Dental disease

  • Obesity

  • Respiratory problems due to pasteurella, pulmonary mites, dental disease

  • Baylisascaris

  • Antibiotic choices as for rabbits and guinea pigs

For more information on prairie dogs see references

9. Hedgehogs

There currently exists a "fad" with captive bred African Pygmy or Central African hedgehogs (Atelerix albiventris). Other species (14) of hedgehog also occur in Africa, Europe and Asia. Much is written about the widely protected European hedgehog (Erinaceus europaeus), but little is known about the others.

Hedgehog
Hedgehog

9.1. Basic data

  • Weight 250 - 600g, live 5-10 years in captivity, 3-4 years in the wild

  • Rectal temp. 95.2ºF (35ºC)

  • Temperate climate, lots of cover, hibernate at low temperatures < 65ºF (<19ºC) - discourage in captivity

  • Solitary and nocturnal

  • Insectivores (with rare vegetation)

  • Roll up as a defensive reaction

  • "self-anointing" or "anting" behavior in response to foreign materials

  • Exquisite sense of smell

Anting
Anting

9.2. Husbandry

  • Need secure cage (can climb) with smooth walls and bottom

  • Clean frequently

  • Bedding of shredded newspaper

  • Hide box

  • Cover preferred

  • 75-85F, will hibernate at low temps., suffer heat stress at higher temps.

  • Exercise/environmental enrichment important (special exercise wheel with solid running surface)

  • Keep solitary, rarely can be housed in compatible groups if cage is large enough

Hedgehog jog
Hedgehog jog

9.3. Diet

  • Natural diet of insects, crustaceans and vegetable matter.

  • Captive diet

    • Commercial diet (preferred) or dry cat food (high protein, low cal)

    • Worms, mealworms, crickets, etc.

    • Fruits and vegetables

  • Learn to drink from a sipper bottle

  • Prone to obesity

Obese hedgehog with mites
Obese hedgehog with mites

9.4. Restraint

  • Examination difficult: usually need drugs!

  • Isoflurane is recommended.

  • Use gloves for handling.

9.5. Health issues

Acariasis
Acariasis

  • Neoplasia very common - multiple organs: squamous cell carcinoma, mast cell, fibrosarcoma

  • Ectoparasites extremely common - mites, ticks and fleas

  • OK to use ivermectin (0.2 - 0.5 mg/kg) and pyrethrin based shampoos

  • Papillomas

  • Fungal dermititis, Trychophyton mentagrophytes var. echinacei

  • Bordetella and Pastuerella rhinitis and pneumonia

  • Salmonella, Yersinia pseudotuberculosis and GI infections

  • Abscesses (incl. mycobacterium)

  • Foot and mouth disease virus - oral lesions (native African animals only)

  • Obesity, hepatic lipidosis, skin fold dermatitis

  • Oral foreign bodies

  • Dental disease, tartar, gingivitis

  • Congestive heart failure/cardiomyopathy

  • Interstitial nephritis

  • Neurologic demyelinating disease ("Wobbly Hedgehog Disease")

    • Hedgehogs with this disorder walk in an uncoordinated way or show paresis or paralysis, but are usually in perfect mental status

    • Take care not to over diagnose this disease for sick hedgehogs that show generalized depression as a clinical sign of other diseases

10. Sugar Gliders

The sugar glider has recently become a popular exotic pet, available in many states, but still illegal in MA. It is a true marsupial in the possum family from Australia and New Guinea: Petaurus brevicepts. Animals available in the US are captive bred.

10.1. Basic data

  • Nocturnal

  • Marsupial reproduction

  • Social habits (6-10 in a group in the wild) DO NOT KEEP THEM ALONE

  • Patagium forms the gliding membrane as in a flying squirrel

  • Body weight 90-130 g., males > females

  • Cloacal temperature 90ºF (32ºC)

  • Life span 10-12 yrs. in captivity

10.2. Husbandry and nutrition

  • Need lots of space and lots of socialization/attention (min. cage 20"x20"x36")

  • Wire caging OK, with climbing structures and nest box or sleeping pouch high in cage

  • Ideal ambient temperature 75-80 F

  • Natural diet

    • Sap/gum from eucalyptus and acacia

    • Nectar/pollen, manna, honeydew

    • Insects and spiders

    • Variable with the season

  • Captive diet (beware of erroneous literature)

    • Nectar

    • Insects and other protein (eggs, pinkies, high quality cat food)

    • Limited fruits and vegetables

    • Commercial sugar glider diets

    • Vitamin and mineral supplement (esp. calcium)

10.3. Health issues

  • Malnutrition

  • Obesity

  • Metabolic bone disease -hypocalcemia may present as a true emergency

  • Dental disease; DO NOT trim incisors, these are not rodents!

  • Infectious diseases

    • Pasteurellosis

    • C. piliforme

    • Giardiasis

    • Cryptosporidiosis

    • Toxoplasmosis

  • Lymphoid neoplasias

  • Self mutilation, stress associated

    • Sugar gliders become very depressed when housed alone often resulting in self-mutilation

    • Being used as a model animal to study clinical depression

  • Trauma

11. References and Resources

Conservation Medicine Challenges

Supplemental Readings

1, 2, 3

11.1. Professional Organizations

Association of Exotic Mammal Veterinarians (AEMV) http://www.aemv.org/

11.2. Web sites

Hedgehog FAQ http://www.hedgehoghollow.com/faq/

International Sugar Glider Association http://www.isga.org/

Anatomy and species natural history: http://animaldiversity.ummz.umich.edu/site/index.html

Nutrition and feeds: http://www.exoticnutrition.com/

11.3. Products mentioned in the text

Special rabbit/rodent dental pack is available from: Spectrum 4575 Hudson Drive Stow, OH 44224 Phone 800-444-5644 Fax 330-686-4555 spectrumsurgical.com Rabbit Dental Pack order #54-800

11.4. Journals

Exotic DVM at http://www.exoticdvm.com (this journal is free for students)

Journal of Exotic Pet Medicine. official Journal of the Association of Exotic Mammal Veterinarians. New York : Elsevier/Saunders.

Veterinary Clinics of North America. Exotic Animal Practice. Philadelphia, PA : W.B. Saunders Co., 1998-

11.5. Articles and Texts

Abou-Madi, N. Anesthesia and analgesia of small mammals. In: Recent Advances in Veterinary Anesthesia and Analgesia: Companion Animals , Gleed R.D. and Ludders J.W. (Eds.). International Veterinary Information Service, Ithaca NY (www.ivis.org)

Bennett, R. Avery. Husbandry and medicine of hedgehogs. Proceedings of the Annual Convention and Expo of the Association of Avian Veterinarinas, 2000, pp. 109-114.

Bennett, R. Avery. Husbandry and medicine of prairie dogs. Proceedings of the Annual Convention and Expo of the Association of Avian Veterinarinas, 2000, pp. 79-83.

Booth, RJ. General husbandry and medical care of sugar gliders. IN Kirk's Current Veterinary Therapy XIII. Bonagura JD, ed. Philadelphia : W.B. Sauders, 2000, pp. 1157-1163.

Capello, Vittorio. Pet Hamster Medicine and Surgery - Part II: Clinical evaluation and therapeutics. Exotic DVM, v. 3.4, 2001: 33-39.

Capello, Vittorio. Dental diseases and surgical treatment in pet rodents. Exotic DVM, 5.3 July 2003: 21-27.

Childs, James E., et al. Surveillance and spatiotemporal associations of rabies in rodents and lagomorphs in the United States, 1985-1994. Journal of Wildlife Diseases, 33 (1), 1997, pp. 20-27.

Done LB, et al. Necropsy lesions by body systems in African hedgehogs (Atelerix albiventris): clues to clinical diagnosis. Proc Joint Meeting AAZV/AAWV 1992, pp. 110-112.

Fowler, Murray E. and Miller, R. Eric. Zoo and Wild Animal Medicine, 5th ed. Saunders, 2003. Chapters: 34, 35, 43.

Fudge, Alan M. Laboratory Medicine, Avian and Exotic Pets. Philadelphia : W.B. Saunders Co., 2000.

Quesenberry, Katherine E., James W. Carpenter, Peter Quesenberry. Ferrets, Rabbits and Rodents: Clinical Medicine and Surgery Includes Sugar Gliders and Hedgehogs. 2nd ed. Philadelphia: WB Saunders Co., c2003

Hoefer HL. Hedgehogs. Vet Clin of North America Small Animal Practice, vol. 24, 1994, pp. 113-120.

Isenbugel E., Baumgartener, RA. Disease of the hedgehog. In: Fowler, Murray E. Zoo and Wild Animal Medicine, Current Therapy 3. Philadelphia, WB Saunders, 1993, pp. 294-302.

Johnson-Delaney, Cathy A. Exotic Companion Medicine Handbook for Veterinarians. Wingers Pub. Inc., 1996.

Lightfoot, Teresa L. ICE First Step Program 2003

Kraus VB, Huebner JL, Stabler T, Flahiff CM, Setton LA, Fink C, Vilim V, Clark AG. Ascorbic acid increases the severity of spontaneous knee osteoarthritis in a guinea pig model. Arthritis Rheum. 2004 Jun;50(6):1822-31

Lightfoot, TL. Clinical examination of chinchillas, hedgehogs, prairies dogs, and sugar gliders. Vet Clinics of North America, Exotic Animal Practice, Vol. 2, 1999, pp. 447-469.

Morales, Edmundo. The Guinea Pig: Healing, Food, and Ritual in the Andes. University of Arizona Press, 1995.

Ness, Robert D. Sugar glider (Petaurus bevideps): general husbandry and medicine. Proceedings of the Annual Conference of the Association of Avian Veterinarians, 2000, pp. 99-107.

Palmer, AC, et al. Paralysis in hedgehogs (erinaceus europaeus) associated with demyelination. Vet Record, Vol 143, 1998, pp. 550-552.

Pye, GW, Carpenter JW. A guide to medicine and surgery in sugar gliders. Veterinary Medicine, 1999: 891-905.

Quesenberry, Katherine E., James W. Carpenter, Peter Quesenberry. Ferrets, Rabbits and Rodents: Clinical Medicine and Surgery Includes Sugar Gliders and Hedgehogs. 2nd ed. Philadelphia: WB Saunders Co., c2003

Raymond, James T., and M. R. White. Necropsy and histopathologic findings in 14 African Hedgehogs (Atelerix albiventris): a retrospective study. JZWM, v. 30 (2), 1999: 273-277.

Raymond, James T. and Michael M. Garner. Cardiomyopathy in captive African hedgehogs (Atelerix albiventris). Proceedings of the AAZV and IAAAM Joint Conference, 2000, p. 245.

Reeve H. Hedghogs. London, T & AD Poyser Ltd, 1994.

Smith, AJ. Husbandry and nutrition of hedgehogs. Vet Clinical of North American, Exotic Animal Practice, vol. 2, 1999, pp. 127-141.

Veterinary Clinics of North America. Exotic Animal Practice. Philadelphia, PA : W.B. Saunders Co., 1998-

Wheler, Colette L., Grahn, Bruce H., Pocknell, Ann M. Unilateral proptosis and orbital cellulitis in eight african hedgehogs (Atelerix albiventris). Journal of Zoo and Wildlife Medicine, v32, 2001: 236-241.

Wrobel D, Brown SA. The Hedgehog, an Owner's Guide to a Happy Healthy Pet. New York, Howell Book House, 1997.