What is the genus and species of the:
Syrian Hamster
Chinese Hamster
Armenian Hamster
European Hamster
Djungarian Hamster
Mesocricetus auratus
Cricetulus griseus
Cricetulus migratorius
Cricetus cricetus
Phodopus cambelli (Russian dwarf) and Phodopus sungorus (Siberian dwarf).
To which taxonomic family do hamsters belong?
What are some distinguishing characteristics of this family?
Cricetidae - large cheek pouches, short tails, and excess loose skin. They have incisors that grow continuously and cuspidate molars that do not continue to grow.
T/F The Syrian hamster is diurnal.
False. They are nocturnal.
What is the life span and breeding life span of the Syrian hamster?
Ave. life span = 2 years (max. = 3 years) - lifespan may be shorter in female than male depending on strain and source
Breeding life = 1 year (6-8 weeks of age to 15 months of age).
What is a commonly used strain to study CHF and is used extensively in cardiomyopathy research?
Name two additional cardiomyopathic strains
BIO 14.6
BIO 82.62, BIO-TO-2, BIO 53.58 (idiopathic dilative cardiomyopathy), UMX (model of severe childhood autosomal recessive muscular dystrophy).
T/F Hamsters have relatively few spontaneous diseases, but are susceptible to many experimentally induced diseases.
T
T/F The Syrian hamster is resistant to tumor induction by viruses of other species (e.g. SV40).
F - The hamster is susceptible to tumor induction by viruses of other species, such as polyomavirus of mice, SV40, and human adenovirus
T/F Histoplasmosis has been studied extensively in hamsters as they are sensitive to small inocula and are useful for diagnostic purposes.
True - they are susceptible to most deep fungal infections
Conchoid Schaumann bodies are produced during __________ and __________ infections.
mycobacterial and leishmanial
Hamsters infected with ___________are used as models of local infection of the respiratory tract.
Mycoplasma pneumoniae
Name two other infectious diseases to which Syrian hamsters are susceptible.
tuberculosis, leprosy, atypical mycobacterial infections, leptospirosis, and various viral, protozoal and helminthic infections.
Hamsters are useful models of prion diseases because of their susceptibility to agents such as____________________.
scrapie, transmissible mink encepholopathy (TME), CJD, and Gerstmann-Staussler syndrome (GSS)
List the unique attributes of the hamster cheek pouch and name two types of studies for which this anatomic site is useful.
They do not contain glands, they are rich in mast cells, easily everted with blood flow intact, lack an intact lymphatic drainage pathway (“immunologically privileged”), decreased density of Langerhans cells.
Used for microvascular studies of inflammation, tumor growth, vascular smooth muscle function
Transplantation of foreign tissue without immunologic rejection - this research use has largely been replaced by the nude mouse
Considered the best carcinogenesis model for evaluation of human oral cancer development.
T/F Related to the short gestation period of the Syrian hamster, the ontogeny of the thymic system and associated cellular immunity is delayed compared to other rodents.
True
Which class of immunoglobulin has not been defined in the hamster?
IgD; also, some inbred strains are deficient in the sixth component of complement and another isotype of IgG (IgG3) has been described in others.
At what temperature will hamsters generally hibernate?
5 C +/- 2
T/F A hamster does not fatten prior to hibernation, and will starve if it does not wake periodically to eat.
T
Hibernation is associated with desaturation of white or brown adipose tissue? Select one.
White
Syrian and Chinese hamsters are among the most radioresistant or radiosensitive mammals known.
Radioresistant
What type of dental studies are Syrian hamsters used for?
Study of etiological factors for caries development - they develop caries in response to CHO in diets
The flank glands of Syrian hamsters are ____________glands that produce secretions in response to ________________.
Sebaceous
Androgens
Are flank glands more prominent in the male or female hamsters?
Male
True or False: Antibodies to the MAdV-2 (K87) strain of mouse adenovirus are commonly present in hamsters from commercial suppliers in the US.
True
True or False: Adenovirus commonly causes clinical signs in hamsters.
False - infected hamsters are asymptomatic
Name the pathologic hallmark of adenoviral infection in the hamster.
Large, amphophilic intranuclear inclusions in enterocytes lining villi & goblet cells of jejunum & ileum
Malformed or missing incisors in suckling and weanling hamster pups is indicative of what?
Toolan H-1 virus - a rat parvovirus
Recent data suggests that Hamster Parvovirus is distinct from rat parvovirus, although very closely related
True or False: Hamster parvovirus is over 98% homologous to MPV-3.
True.
Infection in hamsters occurs through interspecies transmission from mice, which are the natural rodent host for this virus.
Name the etiology of transmissible lymphoma in hamsters.
Hamster polyoma virus (HaPV)
Transmissible lymphoma occurs in epizootics among young hamsters
Keratinizing skin tumors of hair follicle origin are caused by what virus?
HaPV - not to be called hamster papillomavirus even though the polyoma virus can cause papilloma-like skin lesions
HaPV is spread by environmental contamination with what excrement?
Urine
True or False: HaPV is oncogenic, but tumor formation is a side effect of infection and not critical to the virus life cycle.
True
Do lymphomas caused by HaPV have detectable infectious virus?
No - this is because HaPV can infect cells lytically with virus replication or transform cells without virus replication.
True or False: HaPV epitheliomas have virus replication in keratinizing epithelium, similar to the behavior of papillomaviruses.
True - HaPV epitheliomas do shed infectious virus, unlike HaPV lymphomas
Explain what may happen when HaPV is introduced into a naïve population of breeding hamsters.
Epizootic of lymphoma with attack rates as high as 80% among young hamsters within 4-30 wk postexposure - this is a diagnostic phenomenon
Infected hamsters may also have epitheliomas, usually around the face and feet.
Once enzootic, incidence of lymphoma declines to much lower levels.
Hamsters with lymphoma appear thin and often have palpable masses in their abdomens. Where do lymphomas usually arise?
In the mesentery, without involvement of the spleen.
Can also occur in axillary & cervical lymphadenopathy
Infiltration of liver, kidney, thymus, other organs may occur.
Why is epizootic HaPV unmistakable?
Lymphoid tumors are otherwise rare in hamsters (especially YOUNG hamsters) and when they occur it is in aged hamsters.
True or False: Trichoepitheliomas have been described in hamsters due to causes other than HaPV.
False
Describe how to effectively eliminate HaPV.
Total depopulation and thorough decontamination of the premises.
The virus is resistant to environmental decontamination.
What is the proposed function of flank glands in Syrian hamsters?
They appear to play a role in the conversion of testosterone to dihydrotestosterone
Used in territorial marking
Flank glands are (resistant/sensitive) to locally applied carcinogens but are (resistant/sensitive) to transformation associated with the administration of estrogens and androgens.
Resistant
Sensitive
T/F Spontaneous bronchiogenic and pulmonary tumors are relatively common in the Syrian hamster.
F: Spontaneous bronchiogenic and pulmonary tumors are rare
Syrian hamsters are good models for chemical carcinogenesis of the respiratory tract.
What two factors make the Syrian hamster a good model for the effects of long term smoke inhalation?
They are resistant to pulmonary infection and are able to decompose nicotine.
What is unique about the stomach of the Syrian hamster?
The esophagus enters between a forestomach and a glandular stomach compartment
The forestomach is similar to that of ruminants in that it has an elevated pH and microorganisms contribute to digestion through fermentation.
T/F Spontaneous tumors of the GI tract are relatively common in the Syrian hamster.
True
Helicobacter aurati has been associated with what disease condition in the Syrian hamster?
Gastritis and intestinal metaplasia
T/F The hamster is similar to mice and rats in that the pancreatic ducts join the common bile duct prior to entering the duodenum.
T
Why is the hamster a good model of pancreatic carcinogenesis?
It is the only animal model in which pancreatic tumors can be induced that are comparable to human tumors, both morphologically and clinically.
The administration of estrogen to male hamsters causes ______________.
Renal tumors
This makes Syrian hamsters one the best models of renal cancer
T/F The hamster is reported to be the first model in which the equivalent of Addisonian adrenal necrosis could be studied.
T
The adrenal glands are larger in the male or female hamsters?
Male - their zona reticularis is upto 3X larger than females
T/F: Sexual dimorphism is seen in the harderian gland of all species of hamsters, with females secreting 100-1000 times more porphyrin than males.
F: This has only been reported in the Syrian hamster.
What unique feature of the hamster oocyte has made it a useful tool in the assessment of human fertility?
The hamster oocyte is penetrable by human spermatozoa, making it useful to aid in the assessment of human fertility using the zona-free hamster oocyte assay. It can also be used to investigate treatments for human male infertility.
Syrian hamsters are an excellent model for studying teratogenic agents because of their short life cycle (18-24 mths).
What day of gestation is the optimal time for teratogenic effects?
The 8th day - when hourly development of the fetal pups can be observed
At what age in M. auratus do the following occur:
Eruption of incisors
Ears open
Hair growth observed
Eyes open
Incisors are present at birth
Ears open at day 5
Hair growth observed at day 9
Eyes open at day 15
Name three ways male and female hamsters distinguished?
Adult females are larger than adult males
Shorter anogenital distance in females
Presence of mammae in female
Observation of posterior scrotum in male.
T/F Serum chemistry parameters may deffer between sexes and strains of hamsters.
True - serum chemistries may differ b/w the sexes, but specifics are not listed in BB
What is the diploid chromosome number of M. auratus?
2N = 44
What is the food consumption of M. auratus during growth and development?
5.5-7 g/day
What is the fluid requirement for hamsters?
30ml/animal/day
How do the nutritional requirements of the Syrian hamster differ from mice and rats with respect to protein source in the diet?
For hamsters, unlike other rodents, soybean meal offers better nutritional efficiency than fish meal.
How does the stomach differ in hamsters compared to other rodents?
The hamster has a forestomach in which the first stage of digestion is a fermentation process that affects the utilization of nutrients.
Syrian hamsters require sources of many of the ________vitamins and also need a source of nonnutritive bulk.
B vitamins
Vitamin__________ has been reported as essential for preventing myocytolysis in cardiomyopathic hamster strains.
Vitamin E
T/F Hamsters changed from a diet of rodent chow to semipurified feed are susceptible to colocolic intussusception within 7-10 days.
True
Due to the hamster’s broad muzzle, how do feeding recommendations for this species differ from those for other rodents?
Feed pellets must be able to fall through the slots of the hopper to the floor or food may be placed directly on the floor of the cage.
Hamsters are more sensitive to the metabolic effects of _____________ and less responsive to ____________ compared to other laboratory rodents.
Corticosteroids
Histamine
Hamsters are very resistant to which opioid?
Morphine - generally has no sedative or hypnotic effects in this species
Male Syrian hamsters are sexually mature when they reach a weight of ________.
90 grams
In female hamsters, estrus begins by 6-8 weeks of age, but it is recommended to withhold breeding until they reach _________grams in weight.
90-100
How long is the estrous cycle in the Syrian hamster?
Four days
Based on the presence of the postovulatory discharge, when is the optimum time to breed the female?
Describe how to manage the breeding animals.
The discharge marks the end of ovulation - usually day 2 of the cycle
Optimum timing for breeding is in the evening of the 3rd day after the postovulatory discharge.
Introduce the female to the male’s cage 2 hours after beginning of the dark cycle. Remove if fighting occurs or if there is no mating within 5 minutes.
How does a female hamster indicate that she is receptive to mating?
She will assume a position of lordosis with hindlegs spread and tail erect
What is the gestation period of the Syrian hamster?
15-18 days
Infertile mating often results in ___________.
Pseudopregnancy
A hamster that is pregnant will have a distinct gain in weight with abdominal distention by _________ days after mating.
10 days after mating
T/F The most common time for parturition is on day 17 of gestation and parturition itself rarely lasts for more than an hour.
False
Parturition usually occurs on day 16 of gestation and usually lasts for >3 hours
In order to decrease the likelihood of cannibalism by the dam, pups should be left undisturbed for the first _________days after birth.
7-10 days
Weaning usually occurs at ___________days of age.
21-28 days
Mature hamsters should be housed:
a) in pairs
b) in groups up to 4 animals
c) singly
c) singly - due to their tendency to fight
_______________ in cedar and pine bedding may induce____________ and should therefore not be used.
Aromatic hydrocarbons
Nonspecific hepatic enzymes - cytochrome P450
What photoperiod is recommended for adult hamsters?
12-14 hour light period
The longer 14 hour period is recommended for breeding
T/F Females are more docile and easier to handle than males.
False: males are more docile than females
What is the causative agent of proliferative enteritis?
Is this a common or uncommon disease of hamsters?
Describe levels of morbidity & mortality.
What age group is affected?
Lawsonia intracellularis
It is among the most commonly recognized disease of the Syrian hamster
It produces high morbidity and high mortality
Young animals - postweaning
What gross lesions are associated with proliferative enteritis?
Segmental thickening & congestion of the ileum
Enlargement of the mesenteric lymph nodes
Peritonitis & adhesions.
Lawsonia organisms can often be identified in the ____________ using ___________ stain.
Apical cytoplasm of crypt enterocytes
Warthin-Starry silver stain
Lesions associated with proliferative enteritis develop in two stages. The first involves________________ and the second involves_______________.
Hyperplasia of the epithelium lining the crypts and villi
Granulomatous inflammation in the submucosa and muscularis
Name three bacteria associated with pneumonia in hamsters.
Streptococcus pneumoniae, Pasteurella pneumotropica, Corynebacterium paulometabulum
What is the etilogic agent of Tyzzer’s disease in hamsters?
What clinical signs are associated with Tyzzer’s disease in hamsters?
What age group is primarily affected?
What gross & histopathologic lesions are observed?
Clostridium piliforme
Roughened hair coat, diarrhea, & high mortality
Usually in animals of weaning age or immunosuppressed animals
Enterocolitis, multifocal necrotizing hepatitis & myocarditis w/ bundles of intracellular bacilli ID with silver stain
Enteritis associated with what organism has been linked to inappropriate antibiotic administration, stress, and experimental administration?
What antibiotics are associated with enterocolitis in hamsters?
What is the typical presentation of antibiotic associated enterocolitis?
Clostridium difficile
Lincomycin, clindamycin, ampicillin, erythromycin, cephalosporins, gentamicin, penicillin
Profuse diarrhea with high mortality occurring 2-10 days following administration of antibiotics
T/F: Hamster models of atherosclerosis placed on high-fat diets may be prone to develop enteric disease associated with toxigenic C. difficile.
True
T/F: Salmonellosis is relatively common in hamsters.
What serotypes are Syrian hamsters susceptible to?
False - although Syrian hamsters are very susceptible to infection with Salmonella
S. typhimurium and S. enteritidis are the most frequent isolates
What gross lesions are associated with salmonellosis in the hamster?
Multifocal hepatic necrosi & interstitial pneumonitis, but no enteritis
Name five viral pathogens for which it is recommended to monitor hamsters colonies.
- LCMV
- PVM
- Reo 3
- Sendai virus
- Rodent protoparvovirus
Name two types of disease caused by LCMV in hamsters.
- Chronic, progressive fatal characterized by wasting (congenital or newborn infection)
- Subclinical infection (adult infection)
How is LCMV transmitted in hamsters?
- Transplantable tumors - SIGNIFICANT source of virus in the laboratory
- Direct contact
- Fomites
- Aerosols (attributable to excretion of high viral titers in urine) - cage to cage transmission via aerosols DOES NOT appear to occur commonly
- Vertical transmission
What histopathologic lesions are associated with LCMV?
How is LCMV diagnosed in hamsters?
lymphocytic infiltration of the liver, lung, pancreas, kidney, spleen, meninges, and brain
Chronic glomerulonephropathy and vasculitis - immune complex dz
Serology is used to confirm the diagnosis: animals usually remain seropositive for a long time
Some infected hamsters have anti-complement activity that complicates interpretation of the complement fixation test
T/F: LCMV is not transmissible from hamsters to humans.
False: LCMV infected hamsters are recognized to be a major source of zoonotic infection in human patients
Sendai Virus is a single stranded-stranded RNA or DNA virus in what family of viruses?
RNA virus in the Paramyxoviridae family
What is the most common clinical course of Sendai virus in the hamster?
What lesions may be seen in affected animals?
Usually subclinical, but may lead to mortality in newborn Syrian and Chinese hamsters
Focal to segmental rhinitis progressing to necrotizing tracheitis and multifocal bronchoalveolitis
What is the best way to prevent Sendai virus infection in hamsters?
Exclusion
To which group of viruses does type C virus belong?
What is it’s signficance in hamsters?
Oncovirus - it is an endogenous retrovirus
It is expressed in tissues & cells as C-type particles without evidence of oncogenicity, but other Oncoviruses are known leukemic agents (FeLV, BoLeukV) so it’s presence may complicate oncology studies
T/F: Protozoa are found in large numbers in fecal smears of hamsters, but their role in enteric disease is not clearly defined.
True
Which oxyurids can infect hamsters?
What are their significance in hamsters?
Infection with S. obvelata (mouse pinworm) is most common
Syphacia criceti & S. mesocriceti are natural hamster pinworms
S. muris (rat pinworm) can infect hamsters
Aspiculuris tetraptera infects Siberian dwarf hamsters
Significance: may affect GI studies & cross-species transmission is a concern
What is the most important internal parasite found in hamsters?
Rodentolepis nana
What is the host range of Rodentolepis nana?
What is significant about the life cycle of R. nana?
Mice, rats, NHPs, & humans
It has both a direct and indirect life cycle
What clinical signs are associated with H.nana in the hamster?
Usually none, but may be associated with intestinal impaction depending on the number of parasites.
What are the two most common causes of acariasis in the hamster?
When are these infestations associated with skin lesions?
Demodex criceti and Demodex aurati
When there identifiable predisposing factors, such as experimental manipulations and/or advanced age
What other mites reportedly infect hamsters?
- Notoedres spp. *
- Ornithonyssus bacoti* (tropical rat mite)
- Spleorodens clethrionomys* (a nasal mite)
What is the most frequently reported malignant neoplasia in the Syrian hamster?
Lymphosarcoma
In which sex is the reported incidence of malignant melanoma higher?
Males (10:1)
What noninfectious disease is a principle cause of death in hamsters in long term studies?
Which sex is more commonly affected by this condition?
Amyloidosis
Females
Name two components of amyloid.
Amyloid A (AA) - derived from amyloid fibrils
AmyloidP (AP), also known as hamster female protein (FP) - regulated by sex hormones
Injection of what compound can experimentally induce amyloidosis in hamsters?
What are the typical lesions observed in amyloidosis?
What stains are used to verify amyloid?
Casein
Kidneys are pale & livers are swollen - kidney, liver & adrenal glands are most commonly affected
Congo red or thioflavin T
Polycystic disease is common in hamsters and __________is the most frequently affected site.
What is the etiology of polycystic disease?
Where else might lesions be identified?
LIVER
Congenital
Epididymis, seminal vesicles, & pancreas
T/F: There is a higher reported incidence of intraperitoneal cysts in European hamsters compared to Syrian hamsters.
True
Antibiotic-associated enterocolitis is observed following administration of antibiotics that are selective for gram_______organisms.
POSITIVE
Hamsters were inadvertently infected with what Leptospira species by inoculation with contaminated tissue?
Leptospira ballum
Hamsters are highly susceptible to experimental inoculation with a number of Leptospira species, but no natural infections have been reported.
Are Syrian hamsters considered permissive or obligatory hibernators? How can hypernation induced?
Are Syrian hamsters capable of estuvation?
Permissive hibernators - induced by low temp, short days, solitude, nesting material, inadequate food stores
Yes - induced by high temperature, low water, and other factors that require a state of dormancy and reduced metabolic activity
Administration of nitrosamides to hamsters is a model for?
pancreatic duct adenocarcinoma
Administration of PGHAM-1 cell line to hamsters is a model for what?
metastatic pancreatic cancer
Name 3 ways to induce diabetes mellitus in hamsters
adminstration of streptozocin
administration of alloxan
high-fat (15%) diet with modest cholesterol
In what way does the hamster serve as a model of Alzheimer’s disease?
Hamsters develop amyloid-like deposits in their brains.
What is the weaning age of hamsters?
age of maturity?
weight at maturity?
21 days
6-8 weeks
110-120 g
What makes the hamster an excellen model for the evaluation of human oral cancer development?
Cheek pouches are immunologically privileged - they have a lower surface density fo Langerhans cells and no intact lymphatic drainage
Administration of estrogen to male hamsters results in?
renal t umors
Two things of note regarding hamster harderian glands:
1: female Syrian hamsters have up to a thousand times more porphyrin than males.
1. this sexual dimorphism is only seen in the syrian hamster
Infection with HaPyV is associated with what two clinical syndromes?
HaPyV = hamster polyomavirus
- epizootic multicentric lymphoma involving the mesentery, intestines, liver, kidney, and thymus in infected juvenile hamsters
- trichoepitheliomas on the face, feet, neck, back, flanks, and abdomen in juvenile to adult hamsters
What is unusual about HaPyV?
It has tropism for both undifferentiated keratinocytes and lympocytes.
Hamster parvovirus is most homologous to what viral agent in mice?
MPV-3
What is nephrotic syndrome, and what condition is it associated with in hamsters?
low ablumin, ascites, proteinuria
amyloidosis
Demodex cricetuli infests which species of hamster?
Armenian