Exotic Mammals: Rats & Hamsters Flashcards
What zoonotic diseases can rats spread?
- Leptospirosis
- Chlamydiosis
- Yersinia
- Campylobacter
MISCONCEPTION —> rare in domestic rats, more common in wild ones
How are rats classified?
more color varieties, no official breeds
What social environment works best for rats? How should rats be introduced?
groups of 3-4
slowly, can be aggressive if not raised together from a young age —> wrestling is common and can look like aggression
What grooming do rats require?
- toe nail clipping - human nail clipper
- some bathing
What is the ideal caging used for rats? What is avoided?
- multistory
- wire wall for ventilation
- solid flooring and soft bedding/hammock
- 2x2x2 for a single rat, larger for groups
- change food and water bowls daily
scented bedding
What nutrition is recommended for rats? What can be added? What 3 things should be avoided?
commercial balances foods
small amounts of fruit, nuts, greens, and table scraps
- seed mix
- high sugar treats
- dried fruit/vegetables
When do rats reach sexual maturity? How long is their gestation?
4-5 weeks
21-23 days
What 2 parts of the physical exam is especially important for rats?
- incisors - continuously grow —> malocclusions rare in premolars and molars that do not continuously grow
- respiratory system - a bit or porphyrin d/c is normal, resp disease is common!
How should rats be restrained?
cradle in one hand and examined in the other
- can wrap in a towel
- less is more
What is the most common tumor in both male and female rats? What predisposes?
mammary adenomas - can happen anywhere on the body, not just mammary tissue
intact and obese individuals —> hormones from adipose tissue may activate tumors
How are mammary adenomas in rats treated?
surgical removal is often curative - benign, can be massive and well vascularized
In what 4 ways do mammary adenocarcinomas compare to adenomas in rats? What treatment is recommended?
- less common than adenomas
- more aggressive, usually firm and rapidly spreading
- NOT resolved with surgery
- size is NOT a sign of malignancy
if confirmed by biopsy - Tamoxifen is palliative; blocks estrogen response and slows progression
What signs are seen with pituitary adenomas in rats? What can help reduce prevalence?
- variable depending on what hormones it secretes (can cause Cushing’s like syndrome)
- CNS signs due to mechanical disturbances
caloric restriction and early spaying/neutering
What is the most common cause of respiratory disease in rats? Why is it so difficult to treat?
Mycoplasma pulmonis (+ mixed with bacterial, viral, and fungal organisms)
lacks a cell wall
What causes clinical signs and severity of respiratory disease to differ in rats? What is the aim to treatment?
strain, age, immune status, and location of disease (lower > upper)
minimize signs, improve husbandry, ventilate —> very chronic, often non-curable
What is the treatment protocol for early and end-stage respiratory disease in rats? What is added if patients are not responding?
Enrofloxacin + Doxycycline 10-30 days
antibiotics + corticosteroids
nebulization of antibiotics and steroids —> 8 mL saline + 0.5 mL Gentamycin + 0.5 mL Albuterol for 15 mins, 3 times a day for 14 days
What types of lice are more common in rats? How do they affect rats?
sucking > biting —> Simpliplex spinulosa, Anopllura spp > Mallophaga spp (species specific)
can cause anemia and spread disease (hemobartonella)
What mites commonly infect rats?
- Liponsyssus bacoti
- Orthoonyssus bacoti
- Sarcomptes scabiei
- Demodex
How are ectoparasites of rats treated? When is treatment less successful?
- oral Selamectin (safer than oral Ivermectin)
- treat the environment - clean cage, bedding, furniture
- treat other animals in the household
immunosuppression or poor owner compliance
What monitoring is especially necessary in rats undergoing anesthesia? What other monitoring is performed?
small patient —> body temp (use thermal support!)
ECG, capnograph, etc. —> similar to other species
What are some options for venipuncture in rats? What is usually used for lab rats?
- cephalic
- jugular
- medial or lateral saphenous
- cranial vena cava (approach from thoracic inlet)
- tail (warm first!)
- use a small syringe or just the needle to avoid collapsing the vein
retrobulbar and sublingual —> increased trauma
What are the most common surgical procedures performed in rats?
- mass removals
- neuter
- spay
(do as quick as possible, hypothermia is bound to happen)
How is the GIT of hamsters unique? What unique structure of the integument is also seen in hamsters?
have a distinct forestomach with a high pH
hip scent gland —> prominent in males
How are hamsters sexed?
- females tend to be larger, have their anus close to their vulva, and lack noticeable testicles
- males are smaller, have a larger space between their anus and their urethra, and have noticeable testicles
What is important to remember with hamsters at low temperatures?
hibernate at <5 C —> not dead!
What is the average lifespan and adult weight of hamsters?
18-36 months
- MALE = 87-130g
- FEMALE = 95-130g
What is the average HR, RR, and temperature of hamsters?
310-471 bpm
38-110 bpm
- RECTAL = 99.7 F
- AMBIENT = 70-75 F
What caging is preferred for hamsters? What is especially important to set up?
- can be single or multistory
- tunnels and wheels with solid bottoms are important enrichment
- wire cages with small enough bars to keep dwarf breeding inside
- nesting area with paper/cloth (not cotton or synthetic fiber
- bedding made of recycled paper or non-aromatic shavings
separate areas for food, toilet, and exercise
How can blood be collected for hamsters? What is their dentition like?
LIMITED - nail clip, hind limb skin stab, nick tail tip for just enough blood for a smear or PCV
similar to rats, but their lower incisors are longer and have a normal orange color
What is a common aging change to the skin of hamsters? What disease should also be considered?
rough hair coat
Cushing’s —> hair loss, susceptibility to external parasites (mites, demodex)
What are 2 common GI diseases of hamsters?
- diarrhea - wet tail
- proliferative ileitis - common in 3-10 week hamsters caused by Lawsonia intracellularis
What treatment is necessary for proliferative ileitis in hamsters? What complications are associated?
aggressive!
- fluids (SQ)
- feeding + oral glucose
- antibiotics - Enrofloxacin, TMS for 5-7 days
intussusception, obstruction
What causes enterotoxemia in hamsters? Tyzzer’s?
antibiotic use —> Lincosamide, Penicillin (Baytril is preferred!)
Clostridium piliforme —> causes diarrhea
What respiratory is most common in hamsters? What causes it? How is it treated?
purulent rhinitis and pneumonia
Streptococcus spp (G+ diplococci)
Chloramphenicol
What clinical signs are associated with Cushing’s in hamsters? What causes it?
- PU/PD
- polyphagia
- alopecia
- hyperpigmentation
- high cortisol and ALP
adrenocortical tumor or excess adrenocortical secretions —> pituitary tumors less common
What are the most common causes of exophthalmia in hamsters? How is it treated?
- trauma
- sialo dacryoadenitis - tear duct inflammation caused by cytomegalovirus
- excessive restraint
cleanse area and eye with ophthalmic wash, lubricate, retract eyelids, and replace the eye —> local antibiotic ointment, tarsorrhaphy (good prognosis if treated quickly!)
What neoplasia is most common in hamsters? What are the 3 variations?
lymphoma
- hematopoietic - older hamsters; LN, spleen, liver
- cutaneous
- viral - polyomavirus; skin tumors or abdominal masses
