Hystricomorphs Flashcards
What dose of buprenorphine was found to be efficacious in chinchillas?
0.2 mg/kg q6hrs
What drug causes transient neurologic effects consistent with serotonin syndrome in chinchillas when >40 mg/kg administered?
Tramadol
If a 7 year old guinea pig presents with weight loss, a palpable cervical mass, PU/PD and a poor coat, what condition is likely?
Hyperthyroidism
How is hyperthyroidism diagnosed (3 ways) in guinea pigs?
1) Signalment, history, PE
2) elevated TT4 and/or elevated free T4 by ED
3) TSH stimulation test (inj. 100 ug of recombinant human TSH IM and measure T4 pre and 4 hr post) - normal T4 should increase to 1.5x the prestim value
What are the 3 treatment options for hyperthyroidism in guinea pigs?
1) Radioactive iodine
2) oral/TM thyreostatic agents (methimazole, carbimazole)
3) Surgical thyroidectomy
What is the most useful venipuncture site in the degu?
The ventral tail artery
What leukocyte predominates in hystricomorph rodents?
Lymphocytes
What signalment of guinea pigs has more Kurloff cells?
Pregnant females and g pigs treated w/estrogen have the most (but can have low numbers in immature, non=pregnant and non-estrogen treated)
What is significant about hairless guinea pigs normal leukocyte distribution?
They have 40% fewer leukocytes w/lower #s of lymphocytes causing reversal of L:H ratio (have more heterophils)
Why do guinea pigs have slower coagulation times than most rodents?
They have 50% of the plasma prothrombin vs. rats/dogs and have least factor VII, low amounts of factors V and X
What is the most sensitive and specific test for liver disease in hystricomorph rodent?
Bile acids
What test can be used to diagnose diabetes mellitus in guinea pigs?
Fructosamine
What are danger values for blood pH in guinea pigs?
<7 or >7.7
What is the diagnostic criteria to diagnose lead toxicosis in chinchillas w/seizures and blindness?
> 15 ug/dL is suspicious; >25 ug/dL is definitive
How can cortisol be monitored in guinea pigs suspected of cushing’s?
Plasma or saliva
What is the normal pH of guinea pig urine?
pH 8-9 (alkaline)
What degenerative condition causes small white mobile calcium-lipid opacities in the vitreous humor of chinchillas?
Asteroid hyalosis
What 4 organisms are implicated in respiratory illness in elderly, immunosuppressed guinea pigs?
- Bordetella bronchiseptica
- cilia-associated resp. Bacillus
- Streptococcus pneuomoniae
- Streptococcus zooepidemicus
What is the prevalence of reproductive disease (neoplasia, cystic ovaries, pyo/hydrometra) in intact female guinea pigs >6 yrs of age?
Up to 77%
Which ovary is more commonly affected if only 1 has cysts?
The right ovary
What is the most common reproductive system disorder that is age related in chinchillas?
Endometritis
What is the most common reproductive tumor in guinea pigs?
Uterine leiomyoma
What is the USG in most chinchillas?
> 1.050 (but ranged 1.014-1.060)
What urinary findings are common in chinchillas with anorexia?
Ketonuria and decrease in pH (normal ~8.5)
Which is true for urolithiasis in chinchillas?
A. The majority of stones were struvite.
B. Uroliths in the urinary bladder had a better prognosis vs. urethral stones
C. It occurs with equal prevalence in males and females
D. Recurrence rate was 80% with median time to recurrence 68 days
B is true. A - calcium carbonate; C - much more common in males; D - 50%, 68 days correct
What is the most common isolate in chinchillas with conjunctivitis?
Pseudomonas aeruginosa (gram negative); normal flora 94% g+
What empirical ophthalmic medication should be started in chinchillas with conjunctivitis while awaiting C/S results?
Most likely cause is P. aeruginosa and Gentamicin or polymyxin B had best susceptibility (if unavailable next is cipro and neomycin)
What is a normal VHS in chinchillas?
Rads (either lateral) - 7.5-10.4
CT - 7.1-9.4
Although many chinchillas have innocent murmurs, those with grade __ and higher were __ times more likely to have echo abnormalities.
3; 29
Which giardia gene assemblages are considered zoonotic? Have they been found in chinchillas?
A & B; Both have been found and a true zoonotic transmission was documented in a child that ingested chinchilla feces
What cestode can cause anorexia, diarrhea, weight loss and death when high numbers are present in hystricomorphs?
Rodentolepis nana (prev. Hymenolepis nana); direct transmission and no intermediate host needed so superinfection from coprophagy is possible
The cestodes Taenia serialis, pisiformis, multiceps and Echinococcus granulosis and multilocularis use __ as definitive hosts and __ as intermediate hosts.
Carnivores, Rodents including chinchillas
What clinical signs can Taenia spp. and Echinococcus spp. cause in chinchillas?
Areas of SQ edema, cysticerci in thorax, SQ, larynx, pharynx and retropharyngeal area; metacestodes in liver
Which hystricomorph rodents pups are born precocial?
All of them (g pigs, chinchillas, degus)
What is the gestation length in guinea pigs?
59-72 days
What is the gestation length of chinchillas?
105-118 days
What is the gestation length in degus?
87-93 days
What is significant about guinea pig milk and what species is the composition closest to?
High in carbs with higher protein than fat levels; cats
What is the best substitute for chinchilla milk?
Canine milk replacer w/added lactase (equal parts evap. milk and water have also been used)
What is the main energy source in degu milk and what can act as a milk replacer?
Milk fat; canine milk replaced w/added vegetable oil and Lactobacillus
Why should high carbohydrate food items such as root vegetables and fruits be avoided in degus?
They easily enter a hyperinsulinemic state, leading to DM, cataracts and kidney damage
What type of diet should degus be fed from 10 wks on?
Rodent diet and hay (chinchilla/guinea pig pellets resulted in high mortality in young and weight gain in adults)
How is Tyzzer’s disease in guinea pigs commonly transmitted and what guinea pigs are affected?
Via fecal-oral contamination of bedding/food; young/stressed g pigs in poor husbandry situations
What is the most likely diagnosis for a young guinea pig presenting with tenesmus but little to no stool production?
Congenital issue such as atresia ani w/a rectocutaneous fistula
What the the leading cause of mortality in chinchilla kits in a retrospective study of ranched chinchillas?
Enteritis
What are degu pups under 3 months of age prone to due to poor sanitation of water bottles?
Opportunistic Pseudomonas infections
A juvenile guinea pig presents with circular areas of scaling and alopecia on the face and feet. What test should be performed to diagnose the most likely cause of these signs?
fungal culture or PCR
What emerging pathogen of chinchillas can cause rapidly growing ventral cervical masses in young chinchillas?
Streptococcus equi ssp. zooepidemicus
What is the primary pathogen of congenital conjunctivitis in guinea pig pups?
Chlamydia caviae (passed from sow to pup during parturition)
What approach is preferred for castration in guinea pigs and why?
Abdominal approach; significantly lower infection rates
Why is closed castration not recommended in chinchillas?
The vaginal tunic is adhered to surrounding tissues
What does avocado ingestion in guinea pigs cause?
Cardiogenic shock
What does ingestion of oxalate-containing plants results in in guinea pigs?
Oral irritation with small amount, GI upset, renal failure
When should a C-section be pursued in guinea pigs?
Continuous straining for 20 minutes or unproductive contractions for >2 hrs
What should be administered IV if pregnancy toxemia is suspected in guinea pigs?
Dextrose (1-2 mL 50% diluted in 3-5 mL saline), Calcium gluconate IM or slow IV
What is considered the most common malignancy of guinea pigs?
Lymphoma
What is the most common cutaneous neoplasm of guinea pigs?
Trichofolliculoma
What is the most common cause of conjunctivitis in a 6 week old guinea pig?
Chlamydiosis
What is the most likely underlying cause for head tilt in a chinchilla?
Otitis media +/- perforated tympanic membrane
Why is surgical treatment of otitis media in chinchillas unrewarding?
Large size and complex anatomy of middle ear
When is a purse-string suture appropriate for rectal prolapse in chinchillas?
When there is no intussusception present
Why is high calcium in the diet unlikely to contribute to chinchilla urolithiasis risk factors?
Excess dietary calcium is excreted in feces, not urine
Which location of urinary calculi carries a poor prognosis in chinchillas?
Urethral - up to 75% euthanized w/in 24 hours
For which ECM species have ectoparasites not been reported in captivity?
Chinchillas
What is the appearance of fur chewing in chinchillas?
Normal fur on head/distal extremities, shortened fur on dorsum, from lumbar to tail and laterally on flanks
What species have a palatal ostium that connects the oropharynx to the nasopharynx and larynx?
Guinea pigs and chinchillas
Where is the thymus located in guinea pigs?
Extrathoracic in the cranial cervical region (remnant and encapsulated tissue remain after 1 yr of age)
Which hystricomorphs have a thymus that does not atrophy with age?
Chinchillas and degus (cervical portion, mediastinal part does atrophy)
Why is pneumonia most often lobar in guinea pigs and chinchillas?
They have very scarce interlobular/segmental differentiation of lung lobes by connective tissue
What is the significance of multifocal black pinpoint discolorations on the lung surface of guinea pigs postmortem?
Likely no significance - correspond to subpleural anthracosis (not associated w/fibrosis or inflammatory reaction)
What finding is nearly pathognomonic for cavian leukemia?
Leukocytosis of >25000 WBC/mcL
What is recommend as an alternative to nasal swabbing for cytology with UR infections in hystricomorphs?
Nasal lavage (swabbing can worsen resp distress, is more aggressive on nasal mucosa, and will contaminate sample w/blood)
What volume of saline or hypersaline fluid should be used for nasal lavage?
0.2 to 1 mL/kg
What happens to guinea pigs that contract human influenza?
Severe histopath changes in respiratory system - rhinitis, severe bronchointerstitial pneumonia, but almost complete absence of clinical signs
What primary respiratory neoplasia is common in aged guinea pigs according to some sources?
Bronchogenic papillary adenoma
What is the max amount of time a nasogastric feeding tube should be left in place in hystricomorphs?
3 days
Why isn’t the typical bronchopneumonic pattern associated with aspiration pneumonia typically seen in hystricomorphs?
The disease rapidly spreads to the rest of the lung parenchyma
How can ovarian cysts in guinea pigs be differentiated from cystic masses via ultrasound in guinea pigs?
Cysts will have no internal blood flow and masses often have significant blood flow
What is the main finding associated with cardiac disease in guinea pigs?
Pericardial effusion, regularly associated with cardiac tamponade
Which species have a remarkably low corneal sensitivity and negligible ability to produce reflex tears?
Guinea pigs
What % of guinea pigs becoming pregnant if mated during the postpartum estrus (2-15 hrs after delivery)?
70%
How does Gonadorelin result in resolution of follicular cysts in guinea pigs?
It is a GnRH agonist which induces a surge of luteinizing hormone, resulting in luteinization of cysts
Why should deslorelin be avoided in guinea pigs for treatment of follicular cysts?
Results in an intermittent/prolonged vaginal opening, increasing risk of infection
When is the vaginal closure membrane present in healthy chinchillas?
At all times except at parturition and during estrus
What is the most common bacteria in guinea pig pyometra?
Bordetella bronchiseptica and hemolytic Streptococcus spp.
What are the predominant cells during estrus in chinchillas?
Partially to completely cornified superficial epithelial cells (neutrophils should be absent)
