Chapter 9. Biology and Diseases of Chinchillas Flashcards
1
Q
Chinchilla taxonomy
A
Order Rodentia
Suborder Hystrichognatha
Family Chinchillidae
-Related to guinea pigs and degus
2
Q
Two species of chinchilla
A
1) Short-tailed chinchilla: Chinchilla chinchilla
2) Long-tailed chinchilla: Chinchilla lanigera (most common for biomedical research)
- Most captive chinchillas descended from 11 animals captured in early 1920s
3
Q
Natural habitat of chinchillas
A
- Native to South America, specifically dry climate of Andean mountains of Chile, Bolivia, Peru
- Live in colonies in burrow systems
- Both species critically endangered (International Union for Conservation of Nature) - illegal hunting for fur, habitat reduction
4
Q
Chinchillas uses in research
A
- Similarities to human hearing range, anatomical size, accessible tympanic bullae = acoustic research model since 1970s
- Otitis media, cholesteatoma, therapeutic treatment of aural disease, noise and chemical-induced hearing loss, Meniere’s disease, tinnitus, perilymphatic fistulas, cochlear implants, superior canal dehiscence, tympanic membrane perforation repair, stem cell transplants, otic drug safety testing
- Upper resp tract pathogens: Haemophilus influenzae, Moraxella catarrhalis, respiratory syncytial virus
- Hypothyroidism, repair of dural tears, pathogenic biofilm mediators of Pseudomonas aeruginosa, propagation of Taenia solium taeniasis eggs and adults
5
Q
Sources of chinchillas
A
- NOT inbred or widely available commercially
- Moulton Chinchilla Ranch in Rochester, MN (since 1966)
- Local chinchilla fur farms and pet suppliers
6
Q
Chinchilla housing
A
- Similar to rabbits and guinea pigs - modifications may be needed as chinchillas can squeeze through small openings
- Solid bottom caging preferred; suspended metal or plastic okay if perforations no larger than 0.5 in x 0.5 in to prevent foot and leg injuries - should also have a solid floor area
- Chinchillas good at jumping and climbing - multilevel cages provide enrichment
- Items to gnaw for dental health & items to orally manipulate
- Will perch on flat-topped structure
- Line dropping pans with absorbent material
- Dry, draft free environment
7
Q
Housing space for chinchillas
A
- No standard floor space and height requirements
- Pet trade: 1-2 ft2 (0.1-0.2 m2) per animal and 12 in (30 cm) cage height
8
Q
Bedding for chinchilla housing
A
Wood shavings or paper-based products
-NO wood products containing aromatic hydrocarbons (pine shavings) - may affect drug metabolism, predispose to respiratory problems
9
Q
Unique housing requirement for chinchillas?
A
Dust Baths
- Mixtures of silver sand, Fuller’s earth, diatomaceous earth, volcanic ash
- Provide for 15 min daily, or at least several times per week
- Remove baths between uses & do not share between enclosure to prevent disease transmission (ringworm)
- Overuse - eye irritation & dry skin
- Do not give to near-term females or mothers with litters - mastitis and uterine infection
10
Q
Social housing of chinchillas
A
-Are social; should house in same-sex pairs or groups
11
Q
Temperature & humidity for chinchillas
A
Temp: 63-77 F (17-25 C)
Humidity: 30-60%
-Very prone to heat stress - mortality at temps exceeding 90 F (32 C), particularly if humidity also high (>60%)
-Guide to sum units of humidity and temp in F: should not exceed 150
-Can be cold adapted to temps of 32 F (0 C) or lower to stimulate production of thick fur coat
12
Q
Ventilation and light cycle for chinchillas
A
10-15 air changes per hour
12: 12 h light:dark cycle
- May need to alter for breeding
13
Q
Watering for chinchillas
A
- Rarely drink water
- Maintain hydration by licking dew drops and eating plants
- Captive chinchillas adapt to water bottles or automatic watering systems
14
Q
Handling chinchillas
A
- Grasp base of tail with one hand while other hand supports the body
- Never pick up by the tail alone
- Can pick up tamer animals around the thorax while supporting the hind end
15
Q
Furslip in chinchillas
A
A protective mechanism employed to evade predators
- A patch of hair is simultaneously released from the follicles, leaving a bare area of skin
- Rough handling
16
Q
Describe the chinchilla ear.
A
- Like humans, cochlea has 3 turns, readily accessible for microsurgery
- Large, thin-walled tympanic bullae = easy access to middle ear
- Similar range of hearing to humans
- Freely mobile conductive apparatus = malleus & incus are attached by liagments - can move independently; other rodents (mice, gerbils, hamsters) there is bony fusion btwn malleus and tympanic ring
- Round window thinner than humans - useful for ototoxic drug studies
- Age-related hearing loss similar to humans
17
Q
What is the average chinchilla lifespan?
A
9-18 years
18
Q
What is the blood supply for the brain in chinchillas?
A
ONLY the vertebral-basilar artery system
NO internal carotid arteries
19
Q
Do chinchillas have a right coronary artery?
A
No
20
Q
Unique lymphoid tissue features in chinchillas
A
- Thymus located entirely within thorax
- Have discrete nasal-associated lymphoid tissue (NALT) similar to other rodents
21
Q
Describe the chinchilla GI system.
A
- All teeth open-rooted, grow continuously
- Soft palate is continuous with base of tongue, contains palatal ostium - connects oropharynx to rest of pharnyx
- Large intestine 1.5x longer than small intestine
- Coprophagic - cecal pellts taken directly from anus, masticated, swallowed; typically only ingest pellets produced during daytime - higher nitrogen content than night pellets
- Unable to vomit
22
Q
Urine concentrating ability of chinchillas
A
Relatively large renal medulla allows conservation of water; highly concentrated urine
23
Q
Life cycle values for chinchillas
A
- Breeding onset male: 7-9 mth
- Breeding onset female: 4-5 mth
- Cycle length: 20-60 d
- Gestation: 105-120 d (avg 112)
- Postpartum estrus is fertile
- Birth weight: 30-60 g
- Litter size: 1-6 (2-3 most common)
- Weaning age: 6-8 wk
- Breeding life: up to 10 yr
24
Q
Normal physiologic values for chinchillas
A
- Adult body weight: 400-600 g (females can be bigger than males)
- Body temp: 37-38 C (98.6-100.4 F)
- Pulse: 200-350 bpm
- Resp: 45-80/min
- Life span: 9-18 yr
- Food consumption: 30-40 g/day; 5.5g/100g/day
- Water consumption: 10-20 ml/day; 8-9ml/100g/day
25
Q
Chinchilla chromosome number
A
Diploid number - 64
26
Q
Chinchilla diet
A
- Monogastric hind gut fermenters
- High-fiber, low-energy diet with 16-20% protein, 2.5-5.5% fat, 15-23% fiber
- Low protein diet may result in unthriftiness and dry, weak fur
- Pelleted ration; supplement with free-choice grass hay or other high fiber substance
27
Q
How do chinchillas prefer to eat?
A
Sit upright on haunches and hold food in forepaws when eating
-Commercial chinchilla pellets longer than G pig pellets to facilitate this behavior
28
Q
Appropriate treats for chinchillas
A
- Small amounts of washed, dark green leafy veggies
- Avoid high starch or sugar = GI upset
- Avoid mixed rations = chinchillas will pick out only what they like
29
Q
How should food be offered to chinchillas?
A
Suspended food hopper or J-feeder will prevent waster and feed contamination
30
Q
T/F: Chinchillas eat most of their feed during the dark phase
A
True. Chinchillas are nocturnal.
31
Q
Chinchillas behavior
A
- Social animals - house in same sex pairs or small groups; huddling and mutual grooming occur
- Provide solid running wheels to minimize foot and leg injuries
- Require safe items for gnawing
- Not very vocal, but normal vocalizations include soft high-pitched grunts, angry barks, warning whistles
- Can be territorial and spray urine at an intruder
- Like guinea pigs, do not adjust readily to environmental changes
- Nocturnal, but can adapt to diurnal lifestyle in captivity
32
Q
Aggression in chinchillas
A
- Female may be aggressive when in estrus or post-partum, esp towards males
- Intact males may fight
33
Q
Sexing chinchillas
A
Anogenital distance
- Females have prominent urethral papilla (can confuse with penis)
- Males can retract testicles into abdomen
34
Q
Estrous cycle in chinchillas
A
- In Northern hemisphere, seasonally polyestrus from Nov-May
- Estrous cycle lasts 20-60 days (avg 35)
- Estrus last 12-48 hr: opening of vaginal closure membrane, vaginal reddening and discharge
- Waxy vaginal plug normal at onset of estrus
- Female monogamous in wild; can use harem scheme in captivity w/ 1 M for every 4-6 F
35
Q
Caging system for harem breeding in chinchillas
A
- Females fitted with flat metal disc around neck so they cannot leave their own cage
- Tunnel system connecting cages allows male to move freely between cages
- Interested males make a cooing, chuckling noise & both sexes rub chins on the floor
36
Q
Signs of receptivity in females chinchillas
A
- Lordosis and lateral deviation of tail
- Following mating, female may become aggressive towards male - growling, chattering teeth, spraying urine
- Mating may occur several times during night; loss of some fur from female normal during this time
- Ejaculatory plug present for several hours
37
Q
Gestation in chinchillas
A
- 105-120 days
- At about 60 days, mammary tissue enlarges
- Female weight gain of 25-30g/mth initially, with more rapid increase in last month
38
Q
Parturition in chinchillas
A
- Females near parturition become inactive and anorectic; perineal area, mouth and nose become wet with amniotic fluid to signal start of parturition
- Parturition generally at night or early morning
- Labor lasts 1-2 hours or less; generally all kits born within a 4 hr period
- Female will use teeth to pull kits from birth canal
- Dystocia uncommon, but consider C-section if more than 4 hr of unproductive labor
39
Q
Postpartum estrus in chinchillas
A
~12 hr after parturition and lasts for 2 days after which the vaginal closure membrane reforms
40
Q
Chinchillas kits
A
- Avg litter size of 2-3
- Dams do not normally build a nest but nest boxes may reduce mortality
- Birth weight: 30-60 g; kits <25 g unlikely to survive
- Newborns fully furred with complete set of teeth and able to walk within 1 hr
- Eyes open within 24 hr of birth
- Weaning between 6-8 weeks
- Begin to eat small amounts of solid food in first week of life
- Orphans can be fostered onto female with a small litter of approximate small age, or with a litter ready to be weaned - introduce orphans a few hrs after older pups removed
41
Q
Assisted breeding techniquesin chinchillas
A
Electroejaculation, AI, cryopreservation of sperm
42
Q
Infectious agents that chinchillas are susceptible to for model purposes
A
Respiratory syncytial virus Adenovirus Influenza A Vesicular stomatitis virus Moraxella catarrhalis Haemophilus influenzae Streptococcus pneumoniae Pseudomonas aeruginosa Chlaymydia trachomatis
43
Q
Clostridium perfringens in chinchillas
A
- G(+), anaerobic, rod-shaped, spore-forming bacterium
- Type A, B, and D have been reported in chinchillas
- Enterotoxemia & necrotizing enteritis
- Clin signs: diarrhea, abdominal pain, prolapsed rectum, lethargy, recumbency, sudden death
- Commonly found in intestines of animals, people & in the environment
- Necropsy: hemorrhagic enteritis, mild pulmonary edema, spleno- & hepatomegaly, hepatic lipidosis
- Histo: necrotizing & hemoarrhagic enteritis with bacterial aggregates in epithelium and lamina propria; lg intestinal mucosa necrosis, centrilobular hepatic necrosis, hepatic lipidosis, splenic white pulp proliferation, pulmonary edema
- Tx: may not be rewarding d/t rapid clinical progression
- Prevention: sourcing clean animals, proper husbandry, minimize stress, appropriate abx use, provide uncontaminated feed
44
Q
Pathogenesis of C. perfringens
A
- Five toxinotypes: A-E
- Does not invade healthy cells; toxins & enzymes are responsible for disease
- Bacterium & its toxins may be found in both diseased and clinically normal patients
45
Q
Enterotoxin of C. perfringens
A
Encoded by cpe gene
46
Q
Differential diagnosis for C. perfringens in chinchillas
A
- Diagnose by anaerobic culture, bacterial identification from intestinal contents, immunoassays, PCR
- Other causes of sudden death: Yersinia sp, Listeria sp, Salmonella, Pseudomonas aeruginosa
47
Q
C. perfringens research complications in chinchillas
A
- Sudden clinical illness and death
- Subclinically infected animals may be source of infx for other animals or people - ZOONOTIC
48
Q
Pseudomonas aeruginosa in chinchillas
A
- G(-), aerobic, rod-shaped
- Most infx subclinical; problem for immunodeficient animals
- Clin signs: anorexia, weight loss, enteritis, diarrhea, pneumonia, conjunctivitis with corneal ulceration, inguinal & genital pustules, otitis with neuro signs (facial paralysis, heat tilt, ataxia, circling, rolling)
- Ubiquitous in soil and water; get from contaminated water
- Dx: swabs of oral cavity, feces, water bottles; culture from lesions or blood
49
Q
Necropsy findings of Pseudomonas aeruginosa in chinchillas
A
- Depends on location of infection
- Necropsy: Caseous yellow material in the external ear canal, mottled and congested lungs, small pustules with thick whitet exudate in inguinal & genital skin, enlarged & reddened inguinal LNs, yellow friable liver
- Histo: Otitis - bacterial colonies in tympanic bullae & inner ear; skin infection: hemorrha,e SC edema, inflammation; mesenteric LN microabscesses, subcapsular hemorrhae, neutrophil inflamm; septicemia in liver and lunb
50
Q
Control & treatment of Pseudomonas aeruginosa in chinchillas
A
- Present in many rodent colonies; not always considered excluded
- Treatment of water supply: acidification, autoclaving, RO, chlorine, filtering; biofilms may prevent complete sterilization
- Abx tx of animals already showing severe signs unlikely to be successful
51
Q
Research complications of Pseudomonas aeruginosa in chinchillas
A
- Infx in immunocompetent animals not a significant research impact
- Animals that are clinical may not be suitable research candidates
52
Q
Yersinia spp. in chinchillas
A
- G(-), rod-shaped, facultative anaerobic bacteria
- Y. pseudotuberculosis & Y. enterocolitica reported in chinchillas
- Clin signs: subclinical infx possible; sporadic deaths; anorexia, weight loss, lethargy, excessive salivation, diarrhea
- ZOONOTIC
- Transmission: fecal-oral; vertical transmission via milk
- Necropsy: gray-white firm, nodular foci w/ thick purulent material in liver, spleen, intestinal tract, LNs, less frequently in lungs; hepatio- splenomegaly
- Mucosal hemorrhage & ulceration of ileum, cecum, colon; granulomatous lesions in liver, spleen, lung
- Dx: bacterial culture from lesioned organs, intestinal tract, blood
- Ddx: Listeria spp, Salmonella
53
Q
Yersinia spp. treatment in chinchillas
A
- Tetracycline antibiotics orally or in the drinking water; may not be successful in severely ill animals
- Prevention: sourcing from clean colonies, elimination of SC infected animals, environmental decontamination
- Research complications: unexpected death may interfere with research; source of ZOONOTIC infx
54
Q
Salmonella
A
- G(-), ubiquitous, flagellated, non-spore forming, facultative anaerobic
- Family Enterobacteriaceae
- Genus contains 2 species: S. bongori - infx mainly poikilotherms & rarely humans; S. enterica has ~2500 serovars
- S. dublin, S. enteritidis, S. sofia, S. pullorum, S. typhimurium, S. arizona have been reported in chinchillas
55
Q
Samonella in chinchillas
A
- Clin signs: subclinical carriers; sudden death with obvious clinical signs; septicemia, anorexia, weight loss, lethargy, diarrhea +/- hemorrhage, tremors, local paralysis, mucopurulent or hemorrhagic vaginal secretions, abortions
- Infections have not been reported in lab chinchillas (pet & fur trade)
- All ages susceptible
- Transmission: fecal-oral
- Necropsy: gastritis, enteritis, extensive cecal ulcerations, enlarged spleen with necroti foci, hepatitis with focal necrosis, cholecystitis, hemorrhagic & mucopurulent endometritis, evidence of septicemia
- Dx: culture
- Ddx: coliforms, Pseudomonas aeruginosa, Clostridium sp, Listeria moncytogenes, Yersinia pseudotuberculosis, parasites, coccidia
56
Q
Pathogenesis of salmonella
A
- Ingested and then colonize the intestines by attaching to the tips of the intestinal villi
- Host inflammatory response & intestinal injury results from gastroenteritis
- Salmonella may persist in enterocytes, M cells, macrophages
- Virulent strains may cause bacteremia
57
Q
Salmonella treatment in chinchillas
A
- Oxytetracycline, chloramphenicol, enrofloxain
- Zoonotic potential & subclinical carrier status
- Research complications: clinical disease and sudden death; subclinical carriers may be source of contamination of other animals
58
Q
Listeria spp. in chinchillas
A
- G(+), beta-hemolytic, intracellular, facultative anaerobic, rod-shaped
- L. monocytogenes and L. ivanovii have been reported in chinchillas
- Clin signs: subclinical; septicemia, encephalitis, abortions
- In chinchillas - generally more common to see the septicemic form w/ multiple visceral abscesses - anorexia, lethargy, abdominal discomfort, diarrhea or decreased fecal production, rectal prolapse, torticollis & ataxia with encephalitis
- May be illness of short duration (1-4 days) prior to death or sudden death
- Infx of lab chinchillas rare (fur trade)
59
Q
Pathogenesis of Listeria spp.
A
- Can be found in soil, water, sewage, decaying vegetation, insects, silage, intestinal tract of healthy animals
- All ages of animals are susceptible
- Subclinically infected animals can be source of infx of other animals
- Contaminated hay and feed suspected sources of infection in chinchillas
- Bacteria ingested - disrupt cecal and intestinal barrier - colonize liver - spread to other organs via blood - bacteria able to invade and survive in macrophages, epithelial cells, hepatocytes, endothelial cells, etc.
- Chinchillas most susceptible to septicemic form
60
Q
Necropsy findings of Listeria spp.
A
Necropsy: septicemic spread of bacteria - focal necrosis and abscesses in various tissues; white to yellow foci on liver, spleen, cecum, intestines, mesentery, mesenteric LNs
- Spleen & adrenal enlargement, cecal impaction, hemorrhagic enteritis, intussusception, myocardial abscesses, pleuritis, patchy pneumonia, necrotic metritis, mucometra, miliary necrotic foxi in liver
- Histo: focal areas of necrotic debris, polymorphonuclear and mononuclear cell infiltrates, bacterial colonies in liver, spleen, intestines, mesenteric LNs; microabscesses kidney, cerebrum, brain stem, adrenal glands; pleuritis, interstitial pneumonia with thickened alveolar walls, foamy alveolar macrophages, dispersed bacterial colonies
61
Q
Diagnosis of Listeria in chinchillas
A
- Bacterial culture, IHC
- Ddx: Yersinia pseudotuberculosis, Salmonella
62
Q
Control and treatment of Listeria in chinchillas
A
- Oxytetracycline, chloramphenicol - may not be successful when clin signs apparent or warranted d/t ZOONOTIC potential
- Eliminate source of contamination & decontaminate environment
- Research complications - infected chinchillas may die ro have signs of clinical disease
63
Q
Helicobacter spp. in chinchillas
A
- Confirmed disease has not been reported -Association with a gastric adenocarcinoma described - death after 5 days lethargy; markedly thickened gastric wall, white plaques and nodules on gastric serosa, firm white transmural mass oblitering gastric lumen, numerous gastric ulcers
- Dx: PCR
- Other associated necropsy findings in chinchillas: gastritis, lymphoid hyperplasia, intestinal metaplasia/dysplasia
64
Q
Campylobacter in chinchillas
A
-Case report of C. lanienae in lab chinchillas: Gastritis, duodenitis, typhlocolitis in juvenile males
65
Q
Klebsiella pneumoniae in chinchillas
A
- One report of K. pneumoniae in a breeding colony: anorexia, depression, resp distress, diarrhea; death after 5 days
- Necropsy: congestion & consolidation of lungs, hydrothorax, cardiomegaly, gastroenteritis, subcapsular renal petechial hemorrhage
- Histo: congestion of alveolar capillaries, venous distention in lungs, serous to suppurative exudate in the alveoli, renal tubular necrosis with luminal casts
- Tx: gentamicin attempted but only effective for half of animals
66
Q
Escherichia coli in chinchillas
A
- Septicemia in adult male, experimentally naive chinchilla reported
- Death shortly after presentation with extreme lethargy, tachypnea
- Leukocytosis, neutrophilia with left shift, lymphopenia; azotemia, hyperglycemia, electrolye imbalances, cholestasis, hepatocellular damage
- Histo: neutrophilic enterocolitis with surface bacterial colonization by G(-) rods; lesions suggestive of septicemia (neutrophilic infiltrates, fibrin thrombi, edemain lungs; neutrophilic inflamm of GI tract, neutrophilic tubulonephritis in kidneys - enteric infx w/ subsequent septicemia & DIC
- Dx: culture of kidney and spleen - attaching and effacing E. coli
- Considered part of normal chinchilla flora = opportunistic
67
Q
Other bacterial agents in chinchillas
A
- Chronic respiratory disease: Bordetella sp., Streptococcus sp., Pasteurella sp.
- Enteritis and diarrhea: Proteus sp., E. coli
68
Q
Mycoplasma & Rickettsia in chinchillas
A
NO REPORTS of natural or experimental infx of chinchillas with these agents
69
Q
Chlamydia in chinchillas
A
NO REPORTS of naturally occurring chlamydial infx in chinchillas
70
Q
Herpes Virus in chinchillas
A
- Herpes simplex virus 1 - enveloped DNA virus
- Family Herpesviridae, Genus Simplexvirus
- Clin signs: progressive neurologic dz w/ disorientation, seizures, atonic lateral recumbency; conjunctivitis, mydriasis, uveitis, purulent rhinitis, sudden death
- Tranmission: in one case ocular infx, spread from a person, thought to be source
- Necropsy: Discoloration of perineal fur, pale & friable liver, white foci and coagulative necrosis of adrenal gland, splenic necrosis, polioencephalitis with neuronal necrosis, nonsuppurative meningitis, purulent rhinitis, ulcerative keratitis, uveitis, retinal degeneration & inflamm, optic neuritis, INTRANUCLEAR INCLUSION BODIES
- Dx: IHC, virus isolation & genetic sequencing
- Ddx: consider other causes of neuro dz
- Control: people actively shedding herpes should avoid contact with chinchillas; ZOONOTIC
- Research complications: infected chinchillas may have clinical disease or die
71
Q
Lymphocytic choriomeningitis virus in chinchillas
A
- Susceptible to natural infection
- Infection may be subclinical as in other rodents
- ZOONOTIC
72
Q
Toxoplasmosis in chinchillas
A
- Previously common on fur ranches, now rare
- Necropsy: hemorrhagic lungs, enlarged spleen, enlarged mesenteric LNs
- Tissue cyst formation occurs in sheep, cattle, pigs, horses, dogs, cars, chinchillas, humans
- One report of focal necrotic meningoencephalitis d/t T. gondii with separate brain cysts
- Ddx: Frenkelia
73
Q
Frenkelia in chinchillas
A
- Coccidian parasite of Microtus (voles) and Ondatra zibethicus (muskrat)
- Cyst reported in brain of a lab chinchilla
- Ddx: toxoplasmosis
74
Q
Giardia in chinchillas
A
- Normal chinchillas may harbor, including Giardia duodenalis -may be ZOONOTIC
- Usually subclinical; signs include inappetence, diarrhea, weight loss, poor fur condition
- Stress and poor husbandry may increase Giardia load
- Dx: microscopic identification of trophozoites or cysts in fresh fecal smear; ELISA on feces
- Tx: Albendazole (25 mg/kg PO Q12h for 2 days), fenbendazole (50 mg/kg Po Q24h for 3 days), metronidazole (10-20 mg/kg PO Q12h with caution)
- Treatment may inhibit cyst production rather than fully eradicate = thoroughly disinfect environment to prevent reinfection
75
Q
Other protozoa in chinchillas
A
- Eimeria chinchillae: chinchillas, G pigs, hamsters, mice, rat, rabbit
- Hepatic sarcocystosis: case report of acute death
- Cryptosporidium sp.: gastroenteritis
- Trichomonas muris, T. wenyani, T. minuta, & a form resembling T. microta has all been reported in chinchillas
76
Q
Nematodes in chinchillas
A
-Baylisascaris procyonis: ataxia, torticollis, paralysis, tumbling; exposure was from hay contaminated with raccoon feces
77
Q
Cestodes in chinchillas
A
- Intermediate host for Taenia serialis, Taenia pisiformis, Taenia crassiceps, Echinococcus granulosus, Hymenolepis nana
- Exposure via ingestion of hay contaminated with feces from infected dof
- Echinococcus multilocularis: abdominal distension, multiple hepatic vesicles and cysts
- Taenia coenurus: case of unilateral exophthalmos d/t a cyst comprised of multiple invaginated protoscolices, characterized by a prominent scolex with refractile hooklets, suckers, and abundant calcareous corpuscles
78
Q
Ectoparasites in chinchillas
A
- Reports of ectoparasites in chinchillas quite rare
- Cheyletiella - fur mites, acquired from co-housing with dogs or cats; tx with ivermectin (0.2-0.4 mg/kg SC Q7-14d), 2.5% lime sulfur dips (q7d), pyrethrin powder (q7d)
79
Q
Dermatophytosis in chinchillas
A
- Trichophyton mentagrophytes (most common), Microsporum gypseum, Microsporum canis
- Clin signs: subclinical; well-defined areas of alopecia with scaling, crust formation, erythema - usually non-pruritic & around eyes, nose, head, ears, flanks, tail, forefeet
- Transmission: direct contact with infected person or animal, contact with infected hair or scale on fomites
- T. mentagrophytes & M. canis = ZOONOTIC
- Necropsy: Tissue section stained with Periodic acid Schiff (PAS) or methamine silver stain: detect arthroconidia and hyphae
- Pathogenesis: Colonize keratinized layer of skin, hair, nails; infection does not occur in healthy intact skin; allergic inflammatory response to fungus or its metabolic products; young, old, or immune suppressed predisposed to clinical infx
- Dx: fungal culture with dermatophyte test medium (DTM); skin scraping- clear sample of keratin with chlorolactophenol or KOH; Wood’s lamp for M. canis apple-green fluorescence
- Control: isolate or remove infected animals, disinfect environment
- Tx: may be self-limiting, but if not topical tx includes 2% chlorhexidine/2% miconazole shampoo or 0.2% enilconazole rinse; systemic tx includes terbinafine, itraconazole, ketoconazole
- Research complications: may not be suitable for study if clinical signs
80
Q
Histoplasma capsulatum in chinchillas
A
- Fungus that grows in soil; most common in southeastern, mid-Atlantic, & central US states
- Clin signs: anorexia, weight loss, constipation, tachypnea; death within 2-4 d of resp signs
- H. capsulatum cultured from hay fed to chinchilla
- Necropsy: emphysematous lungs with foci of hemorrhage and bronchopneumonia, enlarged spleen with white nodules, focal necrosis of liver, empty GI tract
- Histo: proliferation of septal cells & focal consolidation in lungs, fibrinous pleuritis, multiple focal granulomas in liver, splenic necrosis & abscessation, glomerular nephritis, distended LN sinuses
- H. capsulatum organisms seen in lungs, liver, spleen, kidneys, LNs
81
Q
GI disorders in chinchillas
A
- Cheek tooth crown and root abnormalities (CT useful to dx)
- Malocclusion w/ periodontitis, alveolar periostitis, alveolar abscessation of maxillary and mandibular cheek teeth
- Esophageal choke: cannot vomit; drooling, dyspnea, anorexia; more common in animals that eat bedding or postparturient females that eat placentas
- Bloat/Tympany: lactating females d/t overeating; also sudden diet changes, GI inflammation; distended abdomen, laterally recumbent, lethargic, dyspneic; tx: gastric tube or trochar deompression - decompression can result in collapse and death
- Gastric trichobezoars: anorexia, fur chewing; papaya tablets & pineapple juice are anecdotal remedies; if dehydrated & anorexic - supplemental fluids, gastric motility stimulants, high fiber food supplements (Critical Care)
82
Q
Constipation in chinchillas
A
- Cause: insufficient roughage or fiber; obesity, intestinal obstruction, intestinal compression due to large fetuses, intestinal intussusception
- Tx: increase fiber (gradually add apples, carrots, dark lettuces), eliminate grains and raisins; enteral fluid therapy (100 ml/kg PO Q24h divided into 4-5 doses); abdominal massage; regular exercise
- If no blockage, cisapride (0.5 mg/kg Po Q8h) may help
- In chronic cases, may have intestinal torsion, impaction of cecum or colonic flexure - need surgery
- Rectal prolapse, intussusception of descending colon and rectum may also occur
- If intussusception ruled out, rectal prolapse can be replaced with dextrose & purse string suture; bland soft diet for 10 days post-prolapse
83
Q
Diabetes mellitus in chinchillas
A
- Clin signs: inappetence, lethargy, weight loss, PU/PD, catarcts
- Hyperglycemia (normal around 210 mg/dl), glucosuria, ketonuria
- Histo: vacuolation of pancreatic islets
- Tx: adjust diet to high protein & complex carbs, low fat; may supplement diet with 50 μg chromium per kg of diet
- Typically hard to regulate in rodents
84
Q
Hyperthyroidism in chinchillas
A
- Clin signs: weight loss, poor body condition, pytalism & malodorous breath, multifocal mild alopecia, unilateral seromucous lacrimation
- Tx: thiamazole ointment applied to concave aspect of pinna (inital dose 0.15 mL then 0.1 ml)
85
Q
Hepatic lipidosis in chinchillas
A
- Common necropsy finding
- May be related to adverse effects of alfalfa in chinchillas, other rodents, rabbits
86
Q
Fur slip in chinchillas
A
- Predator avoidance mechanism - can release a large patch of fur in order to escape
- A clean smooth area of skin is let behind & hair may take several months to grow
87
Q
Bite wounds in chinchillas
A
- Bite wounds with abscessation common in group-housed animals
- Culture - Staphylococcus common
- Females larger than males & more aggressive
88
Q
Traumatic fractures in chinchillas
A
- Fractures of tibia common - assoc w/ animal catching hind limb in cage bar; tibia is longer than the femur
- May be able to stabilize with a needle as an IM pin, or wire or external fixation; place E-collar & on cage rest for 4 weeks minimum
- Bandaging alone seldom successful
- Amputation is well tolerated
89
Q
Dystocia in chinchillas
A
- Usually give birth in early morning
- Dystocia usually assoc w/ a single oversized fetus or malpresentation of one or more kits
- Causes: uterine torsion, uterine inertia
- Tx: initial 0.5-1 IU/kg oxytocin and 25-50 mg/kg SC diluted calcium gluconate; if labor still unproductive after 4 h, C-section
90
Q
Pyometra in chinchillas
A
- Rare
- Acute metritis may be unresponsive to treatment - but plan should include systemic antibiotics +/- a dose of oxytocin
- Tx for chronic pyometra or metritis: OVH w/ systemic abx
91
Q
Placental structure & disease in chinchillas
A
- Interhemal membrane of the placental labyrinth is hemomonochorial = single layer of trophoblast - similar to the guinea pig
- Rare puerperal disorder of trophoblastic emboli in a chinchillas resulting pulmonary embolism
92
Q
Fur ring in chinchillas
A
- Males that groom extensively, frequently produce small amounts of urine, strain to urinate, and/or repeatedly clean penis may be fur ring around the penis and under the prepuce
- Severe cases results in engorged penis and paraphimosis
- Males should be examined for fur rings at least 4x a year; active stud males every few days
- Tx: apply sterile lubricant and cut or gently roll of fur ring
93
Q
Heatstroke in chinchillas
A
- Tempt range of 65-80 F (18.3-26.7 C), especially with high humidity
- Add units of temp in F + humidity = any value greater than 150 may induce heatstroke
- Obesity and periods of increased activity (dust bathing) may also predispose
- Clin signs: reslessness, PD; progress to recumbency, tachypnea, bright red mucous membranes, hyperemic pinnae, thickened saliva, occasionally bloody diarrhea, rectal temp >103 F (39.4 C)
- Tx: cool in tepid water, rehdyrate with IV or SC fluids as needed
94
Q
Fur-Chewing in chinchilals
A
- May barber own and cagemates’ fur
- Area over lumber spine often affected
- Considered behavioral disorder due to overcrowding or stress; boredom, small caging, draughts, high ambient temps
- Tx with fluoxetine (5-10 mg/kg Po Q24h) has been suggested but not described
95
Q
Matted fur in chinchillas
A
- Temps exceeding 80F (26.7 C) at high humidity without adequate access to dust bath
- Recommend dust bath availability for 15 min per day or at least several times a weeks
96
Q
Conjunctivitis in chinchillas
A
- Excessive dust bathing, dirty poor-quality bedding, inadequate cage ventilation, underlying nasolacrimal duct obstruction
- Pseudomonas aeruginosa may be involved
- Dx: florescein stain, conjunctival swab culture
- Tx: restrict dust bath access, lavage conjunctival sac, broad-spectrum antibiotic ophthalmic ointment
- Also systemic abx and supportive care for cases of systemic P. aeruginosa
97
Q
Antibiotic-associated Dysbiosis and Gastroenteritis in chinchillas
A
- Susceptible like guinea pigs
- Abx that target G(+) bacteria, such as penicillins, cephalosporins, clindamycin, lincomycin, erythromycin
98
Q
Metronidazole toxicity in chinchillas
A
-Rare anecdotal reports of liver failure
99
Q
Neoplasia in chinchillas
A
- Despite living up to 20 yr, neoplasia reports in chinchillas are rare
- Neuroblastoma, carcinoma, lipoma, hemangioma, malignant lymphoma, uterine leiomyosarcoma, gastric adenocarcinoma, salivary gland carcinoma, lumbar osteosarcoma
100
Q
Most common congenital abnormality in chinchillas?
A
Malocclusion (may be congenital or traumatic)
101
Q
Embryologic abnormalities in chinchillas
A
Schistosomus reflexus fetus reported
102
Q
Cardiovascular diseases in chinchillas
A
- Cardiomyopathy, congenital septal defects, valvular disease
- Heart murmurs often detected in chinchillas
- Tx is empiric - diuretics, sodium channel blockers like amlodipine
- Fulminant heart failure has a poor prognosis
103
Q
Malocclusion in chinchillas
A
- Dental disease very common
- Malocclusion of cheek teeth more common than incisors
- Continued apical growth of maloccluded teeth results in remodeling of surrounding tissues, facilitating tooth root elongation and palpable rounded bony protrusions along mandible
- Tooth root elongation of maxillary premolars and molars can impinge on the lacrimal ducts, causing epiphora
- Elongation of second and third maxillary molar roots can interfere with retraction of eyes into sockets, rarely causing proptosis
- Formation of spurs or spikes typically on the buccal aspect
- Clin signs: weight loss, drooling (‘slobbers’), unilateral or bilateral epiphora, dysphagia, clear nasal discharge, retained food in mouth
- Food and hair impaction in periodontal pockets may lead to tooth root abscesses
- Prevention: ensure diet include high fiber grass hays & monocotyledonous plants to promote normal chewing
- Damage to tongue or buccal surfaces, or abscessation: meloxicam (0.2-0.5 mg/kg Q24h), enrofloxacin (20 mg/kg Q24h)
- Supportive feeding after tooth trimming and jaw muscles adjust to shorter teeth
104
Q
Ocular age-related abnormalities in chinchillas
A
- Bialteral posterior cortical cataracts
- Asteroid hyalosis
- Reference ranges for IOP vary: around 17-18 mmHg or around 2.9 mm Hg
105
Q
Miscellaneous disorders in chinchillas
A
- Oxalate nephrosis
- Urinary calculi and urolithiasis - calcium carbonate account for 90%; hematuria, stranguria, dysuria; radiographs to confirm diagnosis
- Case of Cuterebra SC myiasis
- Case of lead poisoning with acute convulsions and blindness; tx: chelation therapy with calcium disodium versenate (CaEDTA 30 mg/kg SC Q12h)
