 |
|
回應 |
|
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
Rodent and Small Mammal Medicine
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1. Learning Objectives and Review1.1. Learning Objectives
1.2. Review and Resources on Laboratory Animal MedicinePlease review relevant material from 1st year Comparative anatomy before attending these lectures. Additional material can be found in
The ICE First Step Program on Exotic Small Mammal Medicine, developed by Theresa Lightfoot, is a great supplement to this syllabus. The following material is presented with an emphasis on companion rodents and small mammals. Information on laboratory animal medicine can be obtained from the references listed in the Introduction to Zoological Medicine course and listed below. An excellent review of the diseases of laboratory animals can be found at: Baker, David G. Natural pathogens of laboratory mice, rats, and rabbits and their effects on research. Clinical Microbiology Reviews, vol. 11 (2), April 1998:231-266. There is also an on-line book on the IVIS website: Laboratory Animal Medicine and Management edited by J.D. Reuter and M.A.Suckow. The Webster library also has an excellent CD-ROM on the local network server for your review: ACLAM Lab Animal Medicine and Science Series II. 1.3. '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.'"
2. Rodents2.1. Introduction2.1.1. Taxonomy (abbreviated list)
Free-ranging rodents are distributed worldwide and act as important members of the foodchain. They also often act as vectors of disease.
Captive rodents seen most often:
2.2. General Health Issues2.2.1. Non-infectious diseases
2.2.2. Infectious diseases
2.2.2.1. FOCUS ON HantavirusBunyavirus >>> Hantaviruses
Hantaviruses are an extremely diverse group of viruses which have probably been around for a long time, many as yet undescribed. The primary wild reservoir host is always a rodent species. Hantavirus does not cause disease in the rodent host. Virus is found in rodent kidney and lungs, and the rodent will produce antibodies to the virus. Virus is shed in the saliva, urine and feces. It is transferred horizontally from rodent to rodent. The virus likely occurs in many different rodent species and may be capable of moving from one to another rodent species but each strain seems to prefer a single species host. Hantaviral antigen has also been detected in non-rodent species such as birds of prey, cats, and the desert cottontail associated with the recent "Four Corner's" outbreak. Transmission from the non-rodent hosts is unlikely. The classical human disease associated with hantavirus infection is a renal and hemorrhagic syndrome first described in the1930's in Korea (especially prominent during the Korean War). The virus was not isolated until 1978. Now recognized all over the globe with hotspots in Scandinavia and northeastern Asia. Currently 100,000 - 150,000 cases/year recorded in China alone! Likely attributable to rice farming techniques? 2.2.2.1.1. North American forms of the virusThe first Hantavirus identified in the US was the "Prospect Hill" strain found in the meadow voles, Microtus pennsylvanicus in Maryland and the Midwest. No human disease produced. Human disease first recognized in the US in May, 1993 as the "Four Corner's" strain: this New Mexico disease was seen in previously healthy adults with sudden onset of fever and ARDS. Most patients died quickly with pulmonary edema and respiratory failure. These are atypical symptoms of the other known hanataviruses. PCR testing of patients and local rodents implicated the deer mouse Peromyscus maniculatusas the major vector/reservoir of the Southwestern outbreak. 20-30% of trapped animals proved positive for serology or PCR. Serologic evidence also confirms the virus in the pinon mouse (P.truei), brush mouse (P.boylii), house mouse (Mus musculus), harvest mouse (Reithrodontomys sp.), rock squirrel (Spermophalus vaiegatus), white-throated wood rat (Neotoma albigula), the western chipmunk (Tamias sp.) and others. By December 1993: 48 confirmed cases of human hantavirus pulmonary syndrome in the US from 14 different states (majority in N. Mexico, Arizona, Colorado and Utah). 60% mortality. Investigation into previous cases with similar clinical presentation: earliest confirmed in 1975 (N.Mexico)1991, Oregon, Louisiana (slightly different virus from Peromysicus gossypinus, the cotton mouse) The "Four Corner's" and Louisiana strain are genetically related to the Prospect Hill strain, but are very different from the other strains (indicating that it is not a recent mutation). Three new strains have since been identified in various parts of the US and Canada. Predisposing factors leading to the "Four Corner's" outbreak: El Nino produced an extremely wet winter - large rodent food supply - large rodent reproductive year. 10-fold increase in rodents from May 1992- May1993. 2.2.2.1.2. Disease in humansVirus is transmitted to humans through contact (via inhalation) with rodents or rodent excreta - feces and urine. Rodent bites may also result in infection. Human to human transmission has not been documented. Classic disease (old world) in humans is hemorrhagic fever and renal complications. Hantavirus pulmonary syndrome: history of contact, several days later development of fever, mylagia, headache, gastrointestinal signs followed by cough, cardiopulmonary dysfunction, respiratory failure and shock. No renal involvement in any of the cases!! Mean time from first symptoms to death 7 days. Early diagnosis is obviously important for successful treatment. Incubation period for HPS is felt to be from 1-3 weeks. Symptoms including flu-like signs without upper respiratory component but including a GI complication and a typical hematologic profile should alert medical personnel. History of exposure helps. Rapid serology is available (U. of New Mexico) and PCR has been instrumental in confirming cases (Rockefeller University Laboratory Animal Research Center). The CDC has very strict guidelines for diagnosis of potential and confirmed cases. See their website for more information at: http://www.cdc.gov/ncidod/diseases/hanta/hantvrus.htm This disease is now being diagnosed on a regular basis in humans in both North and South America. The mortality rate has drastically reduced since wider recognition and early intervention has become possible. 2.3. Guinea Pigs
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. 2.3.1. Basic physiologic and anatomic parameters
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 as the rabbit.
Anatomic and physiologic peculiarities include:
2.3.2. Special considerations for husbandry and nutritionGuinea pigs are easy to care for. They can be kept in open cages since they are poor climbers or jumpers. They are normally kept on pine shavings.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. Shavings 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 Guinea pig pellets and fresh fruits and vegetables. Course roughage such as hay may predispose the pig to lymphadenitis. Guinea pigs have an absolute dietary vitamin C requirement. Like some other New World species they are unable to make vitamin C. A deficiency will result in scurvy and eventual death from secondary complications. 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, 22C) 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 never be fed rabbit pellets because they do not have vitamin C added.
2.3.3. Basic diagnostic approaches
2.3.4. Basic therapeutic approachesGuinea 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. 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 chould 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. 2.3.5. Common problems/diseases
Gastrointestinal disorders
Reproductive disorders
Dermatitis
Viral diseases
Bacterial diseases
Parasitic diseases
Neoplastic diseases
2.3.6. Surgery and AnesthesiaSedation 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 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.
Neutering is occasionally performed for birth control reasons. The inguinal ring in the guinea pig is very large. Castration must include closure of the inguinal ring. 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 grave prognosis. The gut of the guinea pig does not tolerate much invasion and usually responds with an intractable ileus. 2.4. Chinchillas2.4.1. Basic physiologic and anatomic parameters
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. They are currently protected as wild animals in their natural range in the Andes mountains.
2.4.2. Special considerations for husbandry and nutritionChinchillas 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. 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 witheld or limited in situations with open wounds or conjunctivitis, etc. 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. They like raisins and yogurt drops especially and care should be taken not to overdo the treats. 2.4.3. Basic diagnostic approaches
2.4.4. Basic therapeutic approachesChinchillas 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. 2.4.5. Common problems/diseases
Dermatitis
Gastrointestinal disorders
Bacterial disorders
Parasitic disorders
2.5. Hamsters, Gerbils, Rats and Mice
2.5.1. Hamsters
Hamsters should be kept alone. Fighting is common. They are nocturnal and will hibernate at temperatures below 5 degrees C. 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). 2.5.1.1. Common problems and diseases
2.5.2. GerbilsGerbils are generally less aggressive and more compatible then hamsters. They are still best kept alone. They are hardier than hamsters. Gerbils have tails. 2.5.3. RatsRattus norvegicus - laboratory rat (albino), hooded rat ("Long Evans stock") ... many strains!!
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 tendancy for obesity. Chromodacryorrhea can be very pronounced in the rat (porphyrins in the urine and other glandular secretions such as tears and nasal discharge). 2.5.3.1. Common problems and diseases
Viral diseases
Parasitic diseases
Neoplasia
2.5.4. MiceMice are rarely seen in small animal practice. They are extensively used in research and well understood from a laboratory animal perspective.
2.5.4.1. Common problems and diseases
Bacterial diseases
Viral diseases
Parasitic diseases
2.6. Prairie Dogs2.6.1. Basic data
2.6.2. Care and husbandry tips
2.6.3. Health issues
For more information on prairie dogs see references 2.7. Tables of Normal Values for Various Rodent Species2.7.1. COMPLETE BLOOD COUNT
2.7.2. SERUM BIOCHEMISTRY
3. Other Small Mammals3.1. HedgehogsThere 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.
3.1.1. Basic data
3.1.2. Husbandry
3.1.3. Diet
3.1.4. Restraint
3.1.5. Health issues
3.2. Sugar GlidersThe 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. 3.2.1. Basic data
3.2.2. Husbandry and nutrition
4. Ancillary Material4.1. Readings4.1.1. Articles and TextsLightfoot, Teresa L. ICE First Step Program 2003 ACLAM Lab Animal Medicine and Science Series II CD-Rom available on the local network in the computer lab in the Webster library. Great resource!! Baker, David G. Natural pathogens of laboratory mice, rats, and rabbits and their effects on research. Clinical Microbiology Reviews, vol. 11 (2), April 1998:231-266. 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. 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. 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. Fox, JG, Cohen, BJ, Loew, FM. Laboratory Animal Medicine, 2nd ed. Orlando, Florida: Academic Press, 2002. Fudge, Alan M. Laboratory Medicine, Avian and Exotic Pets. Philadelphia : W.B. Saunders Co., 2000. Harkness, JE, and JE Wagner. The Biology and Medicine of Rabbits and Rodents. 3rd ed. Lea & Febiger, 1989. 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. Laboratory Animal Medicine and Management edited by J.D. Reuter and M.A.Suckow. 2003-. Levy, Howard and Steven Q. Simpson. Hantavirus pulmonary syndrome. American Journal of Respiratory and Critical Care Medicine, 149, 1994, pp.1710-1713. 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. Malecki, Tinalyn M., et al. Serologic survey for hantavirus infection in domestic animals and coyotes from New Mexico and northeastern Arizona. JAVMA, Vol 212 (7), 1998, pp. 970-973. Mills, James N., et al. Guidelines for working with rodents potentially infected with hantavirus. Journal of Mammalogy, 76 (3), 1995, pp.716-722. Morse, Stephen S. Hantaviruses and the Hantavirus outbreak in the United States. Annals of the New York Academy of Sciences. 740, Dec. 15, 1995. pp. 199-207. 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. Rand, Michael S. Hantavirus: an overview and update. Laboratory Animal Science, 44 (4), 1994, pp.301-304. 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. Schmaljohn, Connie and Brian Hjelle. Hantaviruses: a global disease problem. Emergning Infectious Diseases, 3 (2), 1997: 95-104, 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 2001 32: 236-241 Wrobel D, Brown SA. The Hedgehog, an Owner's Guide to a Happy Healthy Pet. New York, Howell Book House, 1997. Yablonsky, Terri. The mystery of the hantavirus. Laboratory Medicine, 25 (9), 1994, pp. 557-560 4.2. WebsitesAmerican Association for Laboratory Animal Science http://www.aalas.org/ Association of Exotic Mammal Veterinarians (AEMV) http://www.aemv.org/ Hantavirus Pulmonary Syndrome http://www.cdc.gov/ncidod/diseases/hanta/hantvrus.htm Hedgehog FAQ http://www.hedgehoghollow.com/faq/ International Sugar Glider Association http://www.isga.org/ 4.3. Products mentioned in the textSpecial 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 |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 |
 |