Hamsters (BB + P&B) Flashcards
Scientific name: Syrian hamster
Mesocricetus auratus
Scientific name: Chinese hamster
Cricetulus griseus
Scientific name: Armenian hamster
Cricetulus migratorius
Scientific name: Djungarian hamster
Phodopus sungorus, Phodopus campbelli
Scientific name: White-tailed rat, S. African hamster
Mystromys albicaudatus
Scientific name: European hamster
Cricetus cricetus
Hamsters: diurnal or nocturnal?
In lab–>nocturnal
In wild–>diurnal
Syrian hamsters: sexual dimorphism?
Males have large, prominent flank glands, external testicles
Females generally larger
What are advantages of Syrian hamsters?
- Unique anatomical and physiological features (like cheek pouches!)
- Susceptible to carcinogens
- Metabolic dz induced through dietary manipulation
- Genetic dz similar to humans
- Relatively free of pathogens but susceptible to experimental dz
- Permit replication of human adenovirus
Name some Syrian hamster carcinogenesis models
- Pancreatic ductal adenocarcinoma–>induced by nitrosamine, transplantable cell line (PGHAM-1)
- respiratory tumors –>NKK +/- hypoxia
- SV 40 tumor
- Renal tumor–>with exogenous estrogen
Cause of Syrian hamster cardiomyopathy?
defect in sarcoglycan gene (component of dystrophin complex)
Experimental metabolic dz in hamsters?
- Cholesterol cholelithiasis w/ excess dietary cholesterol, sucrose
- Diabetes mellitus
- Atherosclerosis
How to induce diabetes mellitus in hamsters?
- streptozotocin –>APA strain develop diabetes + nephropathy + coronary lesions
- Alloxan (less reliable, less effective)
- High fat diet for 3w (also get bonus obesity, hyperinsulinemia, hyperleptinemia, hypercholesterolemia, hypertriglyceridemia)
Original use of hamsters in research?
Infectious disease models
What day of pregnancy is the optimal time for teratogenic studies in Syrian hamsters?
Day 8–>ability to observe hourly fetal development of pups
When do eyes open in Syrian hamsters?
14-16d
Weaning age for hamsters
21d
Age at maturity for Syrian hamsters
6-8w
Life span for Syrian hamsters
2-3y
Describe the Syrian hamster cheek pouch
- Invagination in oral mucosa, used for temporary storage of food, bedding, pups when stressed
- No glands, rich in mast cells
- Highly vascular; blood supply = external carotid
- No lymphatic drainage (immunologically privileged
- Best animal system for eval of human oral cancer development
Primary circulating leukocyte
lymphocyte
How worried should you be about anisocytosis and polychromasia in Syrian hamsters?
Not very, it’s common
What is unique about the GIT of Syrian hamster?
- Glandular and nonglandular compartmentalized stomach
- Paneth cells in SI
- Cecal semilunar valve
- Pancreatic duct joins common bile duct just before entering duodenum (similar to rat/mouse, different from other mammals)
- Model for pancreatic carcinogenesis
What is unique about the pulmonary system of Syrian hamster?
- Model of chronic bronchitis d/t limited number of glandular strucutres, no respiratory bronchioles
- Vascular bed similar to humans (model of emphysema/COPD with IT porcine pancreatic elastase)
What is unique about the genitourinary system of Syrian hamster?
- Unipapillate kidneys (like mouse, rat, rabbit)
- Kidneys highly responsive to estrogen (bc derived from embryonic germinal ridge)
- Separate urethra and vaginal opening (like other rodents)
Which gender has larger adrenal glands and why?
Males 2x larger d/t zona reticularis
3 unique immunologic aspects of Syrian hamsters?
- Don’t reject skin allografts d/t limited MHC type (they’re all inbred)
- Delayed maturity of cellular immunity d/t short gestation and thymic morphology
- No IgD (like rabbits and pigs, it’s all a GAME)
Which gender of Syrian hamster has larger Harderian glands?
Females (more porphyrin secreted)
Which gender of Syrian hamster has larger flank glands?
Males (role in testosterone production)
What stimulates hibernation in Syrian hamsters?
Temp 5C +/-2, decreased food, decreased hours of light
Diploid chromosome number for Syrian hamsters
44 (2x the size, 2x the chromosomes of other hamsters)
Which vitamin do hamsters not produce like other rodents?
Need external B vitamins
Why should hamsters be fed on the ground vs in a wire hopper?
Their muzzles won’t fit between standard wire sizes
What drugs are Syrian hamsters resistant to? Sensitive to?
Resistant–>histamine, morphine
Sensitive–>corticosteroids
Also antibiotics (Link climbs aboard vans ever seeking gentle princess)–>lincomycin, clindamycin, ampilillin, vancomycin, erythromycin, cephalosporins, gentamicin, penicillin
How long is hamster estrus cycle?
4d
How long is Syrian hamster gestation?
15-18d
Syrian hamster placentation?
Labyrinthine hemochorial placentation–>may see trophoblasts in lungs, uterus during pregnancy
How much space does a <60g hamster need?
10in2
How much space does a >60g hamster need?
13-19in2 AWR: 60-80g get 13in2 80-100g get 16in2 100+g get 19in2
How much space does a female hamster with a litter need?
121in2
AWR specifies dwarf hamsters only need 25in2
Minimum cage height for hamsters?
6in for caging
AWR allowable temperature for indoor housing of hamsters?
60-85F
Can hamsters be housed outdoors?
No according to AWR
AWR how often should food and water receptacles be cleaned?
at least once q2 weeks
AWR how often should primary enclosures be cleaned?
As often as necessary but at least once q2 weeks
AWR what are acceptable methods for sanitizing primary enclosures?
- Hot water (180F)+ soap/detergent
- Detergent + disinfectant
- Live steam
AWR how many hamster can be transported together?
50 (even though we all know 1 is the best answer)
AWR How high do transport cages for hamsters need to be?
6in for most hamsters, 5in for dwarf hamsters
AWR how much space is needed to transport hamsters?
<5w = 5in for dwarf, 7in for other 5-10w = 7.5in for dwarf, 11in for other >10w = 9in for dwarf, 15in for other
Transport regs similar to other species?
- Visualize q4hrs
- if transport >6hrs, must ensure adequate food supply for trip
- 1” letters that say “Live Animal”
- 0.75in projecting rim for ventilation
- 50-85F temperatures, not <45 or >85 for 45min
Humidity and environmental temps for hamsters?
68-79F, 30-70% humidity
2 most common disease syndromes in hamsters?
- Diarrhea
2. pneumonia
Cause of proliferative enteritis
Lawsonia intracellularis
Clinical signs of Lawsonia intracellularis
Diarrhea in weanling hamsters; characteristic moist, matted fur on tail, perineum, ventral abdomen
Type of E. coli most common in hamsters?
Enteroinvasive, strain 1056
Necropsy findings for Lawsonia intracellularis?
Segmental ileal thickening and congestion; mesenteric lymphadenopathy, peritonitis, adhesions
Special stains for Lawsonia intracellularis?
Warthin-Starry silver stain
Diagnosis of Lawsonia intracellularis?
PCR of feces; demonstration of organism in apical cytoplasm of enterocytes
Causative agent of Tyzzers disease
Clostridium piliforme
Transmission of Tyzzers dz
ingestion of spores in feces
clinical signs of Tyzzers dz
Diarrhea,e high mortality in weanlings or immunosuppressed
Necropsy findings for Tyzzers dz
enterocolitis, lymphadenitis, necrotizing hepatitis
diagnosis of Tyzzers dz
demonstration of characteristic organism in affected tissue w Giemsa or silver stain
Organ systems most affected by Tyzzers
intestine, liver, cardiac muscle
Why do hamsters get C dif diarrhea?
- They are ‘exquisitely sensitive’
- Inappropriate abx administration
- stress
- Experimental manipulation
- Heavy environmental contamination
Pathogenesis of C dif?
cecal dysbiosis–>cecal hyperplasia–>bacterial overgrowth–>necrotizing cecitis–>death
Most common serovars of Salmonella
Typhimurium, Enteritidis
Histology findings of Salmonella in hamsters
septic thrombi in veins, venules; multifocal hemorrhagic necrosis without enteritis
Most common species to transmit LCMV to humans
hamsters
Primary reservoir of LCMV
mice
Transmission of LCMV in hamsters
M commonly implantation of tumors w LCMV; oronasal, direct contact, fomites, aerosol
how is LCMV shed in hamsters?
saliva
urine
What ABSL level is required for experimental LCMV models
ABSL3
Natural host of Sendai virus
mice
Clinical signs of Sendai virus in hamsters
subclinical m common
mortality in newborn pups
primary organ system affected by Sendai
respiratory
diagnosis of murine adenovirus
IN inclusions on intestines of young hamsters (otherwise subclinical)
2 syndromes of hamster polyomavirus
- Trichoepithelioma (enzootic)
2. Multicentric lymphoma (epizootic)
Natural host of hamster polyomavirus
european hamster
Control of hamster polyomavirus
Difficult d/t stability in environment; need to cull and decon colony but still could have future outbreaks
Primary differential for runted hamsters with incisor teeth abnormalities, domed cranium, small testes, potbellied appearance
Hamster parvovirus
Clinically significant protozoal infections?
Ha, none
Which pinworms are hamsters susceptible to
All of them
Tapeworm with direct and indirect life cycle
R. nana
Differentiation of R. nana and H. diminuta
R. nana = hooks on scolex
H. diminuta = no hooks on scolex
Most common mites in hamsters
Demodex criceti, D. aurati
Most common malignant neoplasm in Syrian hamsters
lymphosarcoma
Principal cause of death in hamsters on long-term studies
amyloidosis + assoc nephrotic syndrome
sex predilection for amyloidosis in Syrian hamsters
females»_space; males
Classic signs of amyloidosis in syrian hamsters
low albumin, ascites, proteinuria
SQ casein or LPS injection serves as a model for what dz in humans?
amyloidosis, Alzheimers
Most common site of polycistic dz in Syrian hamsters
liver
also cecum, kidneys, ovaries, spleen
Diagnostic necropsy findings for hamsters with atrial thrombosis
Thrombi in left atrium, +/- bilateral ventricular hypertrophy
What is the most common use of Chinese hamsters?
Use of animals overshadowed by use of Chinese hamster ovary cells (CHO) for cell culture to obtain heterologous protein products
Chromosome number of Chinese hamster?
2n = 22
Constant diploidy in cell culture allows stable cell system for assessment of suspected mutagens or carcinogens
How long is the estrus cycle in Chinese hamsters?
4 days
How is pregnancy detected in Chinese hamsters?
closed vagina
dry, pale, scaly perineal tissues 4 days after mating
Most common spontaneous disease model for Chinese hamsters?
Diabetes mellitus
How is diabetes inherited in Chinese hamsters?
recessive inheritance of 4 genes, with the duration, severity, and constancy of glycosuria controlled by modifier genes