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Hamsters (Laboratory) - Pathology (view source)
Revision as of 13:01, 7 January 2011
, 13:01, 7 January 2011no edit summary
==Physiology==
==Physiology==
Please find details of hamster physiology within the WikiNormals section. Physiological information available includes “[[Hamster_Physiology_-_WikiNormals|General]]”, “[[Hamster_Biochemistry|Biochemical]]”, “[[Hamster_Haematology|Haematological]]” and “[[Hamster_Breeds_-_WikiNormals|Breed]]” parameters.
Please find details of hamster physiology within the WikiNormals section. Physiological information available includes “[[Hamster_Physiology_-_WikiNormals|General]]”, “[[Hamster_Biochemistry|Biochemical]]”, “[[Hamster_Haematology|Haematological]]” and “[[Hamster_Breeds_-_WikiNormals|Breed]]” parameters.
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==General Behavioural Characteristics==
==General Behavioural Characteristics==
In particular, Syrian hamsters are solitary and only tolerate company when breeding. Females are easily disturbed and aggressive when lactating or pregnant and in such situations, can be prone to kill other hamsters. Cannibalism is common in stressed primiperous females. Chinese hamsters are particularly pugilistic.
In particular, Syrian hamsters are solitary and only tolerate company when breeding. Females are easily disturbed and aggressive when lactating or pregnant and in such situations, can be prone to kill other hamsters. Cannibalism is common in stressed primiperous females. Chinese hamsters are particularly pugilistic.
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==Anatomy and Histology==
==Anatomy and Histology==
This section has been included to allow familiarisation with the peculiarities of hamster anatomy to provide a context for some of the disease and pathological headings found below. Therefore only anatomical areas with specific features warranting emphasis have been included below;
This section has been included to allow familiarisation with the peculiarities of hamster anatomy to provide a context for some of the disease and pathological headings found below. Therefore only anatomical areas with specific features warranting emphasis have been included below;
===Integumentary System===
===Integumentary System===
'''Hip/Flank Glands'''
'''Hip/Flank Glands'''
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Sebaceous glands with pigmented cells and terminal hairs that secrete during sexual arounsal in both sexes. Also used for olfactory territorial marking.
Sebaceous glands with pigmented cells and terminal hairs that secrete during sexual arounsal in both sexes. Also used for olfactory territorial marking.
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===Reproductive System===
===Reproductive System===
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'''Vaginal Discharge'''
'''Vaginal Discharge'''
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Post-ovulatory dimethyl disulphide is used as a breeding tool by females but is often mistaken for an inflammatory exudate due to its similarity in smell to rotten eggs.
Post-ovulatory dimethyl disulphide is used as a breeding tool by females but is often mistaken for an inflammatory exudate due to its similarity in smell to rotten eggs.
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'''Sexual Dimorphism'''
'''Sexual Dimorphism'''
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Male Syrian hamsters have much larger adrenal glands than females despite females being generally larger than males.
Male Syrian hamsters have much larger adrenal glands than females despite females being generally larger than males.
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'''Fostering Newborn'''
'''Fostering Newborn'''
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This is not usually possible in hamsters as infants are extremely immature when born and 'foreign' infants usually do not accept one another.
This is not usually possible in hamsters as infants are extremely immature when born and 'foreign' infants usually do not accept one another.
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===Urinary System===
===Urinary System===
'''Kidneys'''
'''Kidneys'''
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Extremely long papillae extending into ureters. Very developed water conservation systems.
Extremely long papillae extending into ureters. Very developed water conservation systems.
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===Cardio-Respiratory System===
===Cardio-Respiratory System===
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'''Heart'''
'''Heart'''
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The Purkinje network and sino-atrial node are easily accessible surgically and is a useful physiological feature for some experiments.
The Purkinje network and sino-atrial node are easily accessible surgically and is a useful physiological feature for some experiments.
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===Digestive System===
===Digestive System===
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'''Cheek Pouches'''
'''Cheek Pouches'''
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Hamsters have highly distensible evaginations of the lateral buccal walls which are used to store and transport food.
Hamsters have highly distensible evaginations of the lateral buccal walls which are used to store and transport food.
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'''GI Physiology'''
'''GI Physiology'''
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Long duodenum, long jejunum, short ileum, big cecum, long colon.
Long duodenum, long jejunum, short ileum, big cecum, long colon.
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'''Stomach'''
'''Stomach'''
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Distinct constriction between the forestomach and glandular stomach. No lesser curvature of the stomach resulting in two blind sacs. Pregastric fermentation occurs in hamsters.
Distinct constriction between the forestomach and glandular stomach. No lesser curvature of the stomach resulting in two blind sacs. Pregastric fermentation occurs in hamsters.
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'''Cecum'''
'''Cecum'''
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Apical an basal portions seperated by a semilunar valve. There are a series of 4 valves in the ileocecolic area.
Apical an basal portions seperated by a semilunar valve. There are a series of 4 valves in the ileocecolic area.
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==Diseases==
==Diseases==
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For ease of use, the diseases of hamsters listed below are by body system, or where this is not appropriate in an “Other” category displayed after the body system sections. Those diseases listed below are not exhaustive but rather highlight common diseases encountered with laboratory hamsters.
For ease of use, the diseases of hamsters listed below are by body system, or where this is not appropriate in an “Other” category displayed after the body system sections. Those diseases listed below are not exhaustive but rather highlight common diseases encountered with laboratory hamsters.
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==Integument System==
==Integument System==
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===Dermatophytosis (Ringworm)===
===Dermatophytosis (Ringworm)===
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Macroscopic pathology includes irregular to circular, crusty, flaky skin lesions with reddened margins.
Macroscopic pathology includes irregular to circular, crusty, flaky skin lesions with reddened margins.
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===Mange===
===Mange===
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Clinical signs range from none to alopecia, scaly skin, dermatitis and a rough looking coat. Alopecia generally occurs over the rump and back.
Clinical signs range from none to alopecia, scaly skin, dermatitis and a rough looking coat. Alopecia generally occurs over the rump and back.
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===Lice===
===Lice===
===Other Mite Infestations===
===Other Mite Infestations===
Other species of mite reported in hamsters include ''Sarcoptes scabei, Notodres spp'' (ear mite), ''Speleorodens clethrionomys'' (nasal mite) and ''Ornithonyssus bacoti'' (tropical rat mite).
Other species of mite reported in hamsters include ''Sarcoptes scabei, Notodres spp'' (ear mite), ''Speleorodens clethrionomys'' (nasal mite) and ''Ornithonyssus bacoti'' (tropical rat mite).
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===Abscesses===
===Abscesses===
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Skin abcesses are often caused by trauma including fighting. ''Staphylococcus aureus, Streptococcus spp., Pasturella pneumotropica'' and ''Actinomyces aureus'' have been isolated from skin abcesses.
Skin abcesses are often caused by trauma including fighting. ''Staphylococcus aureus, Streptococcus spp., Pasturella pneumotropica'' and ''Actinomyces aureus'' have been isolated from skin abcesses.
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==Reproductive System==
==Reproductive System==
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'''Reproductive Tract Neoplasms'''
'''Reproductive Tract Neoplasms'''
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This condition most commonly occurs mainly in female syrian hamsters with risk increasing with age.
This condition most commonly occurs mainly in female syrian hamsters with risk increasing with age.
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Uterine carcinomas are seen in 25% of female neoplasm cases.
Uterine carcinomas are seen in 25% of female neoplasm cases.
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===Mastitis===
===Mastitis===
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Macroscopic pathology will include swollen mammary glands and in some cases a mucopurulent exudate. Some females suffering with mastitis may cannabalise their litters.
Macroscopic pathology will include swollen mammary glands and in some cases a mucopurulent exudate. Some females suffering with mastitis may cannabalise their litters.
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==Urinary System==
==Urinary System==
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===Amyloidosis===
===Amyloidosis===
Amyloidosis causes soluable proteins to polymerise into insoluable fibrils resulting in chronic infections and impaired renal function. This condition frequently in older (>1) female hamsters.
Amyloidosis causes soluable proteins to polymerise into insoluable fibrils resulting in chronic infections and impaired renal function. This condition frequently in older (>1) female hamsters.
Macroscopic histology include rough, pale and enlarged kidneys, enlarged adrenal glands and liver at necropsy. Microscopic histopathology may include glomerular hyalinisation, amyloid deposits in tubules and amyloid deposits in other organs including the spleen, liver and adrenals. Microscopic histopathology can be easily visualised with Congo red stain.
Macroscopic histology include rough, pale and enlarged kidneys, enlarged adrenal glands and liver at necropsy. Microscopic histopathology may include glomerular hyalinisation, amyloid deposits in tubules and amyloid deposits in other organs including the spleen, liver and adrenals. Microscopic histopathology can be easily visualised with Congo red stain.
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===Arteriolar Nephrosclerosis (Hamster Nephrosis)===
===Arteriolar Nephrosclerosis (Hamster Nephrosis)===
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Macroscopic pathology on necropsy will include irregular kidneys that may be granular or pitted in appearance. Microscopic histopathology will include interstitial fibrosis, basement membrane thickening, tubular dilation with proteinaceous exosinophilic material and renal casts.
Macroscopic pathology on necropsy will include irregular kidneys that may be granular or pitted in appearance. Microscopic histopathology will include interstitial fibrosis, basement membrane thickening, tubular dilation with proteinaceous exosinophilic material and renal casts.
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===Diabetes Mellitus===
===Diabetes Mellitus===
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Microscopic pathology will include pancreatic islet involution with severe and widespread nuclear pyknotic (irreversible condensation of chromatin in the nucleus of a cell undergoing necrosis or apoptosis), shrunken and eosinophilic cytoplasm with cytoplasmic vacuoles and loss of granules.
Microscopic pathology will include pancreatic islet involution with severe and widespread nuclear pyknotic (irreversible condensation of chromatin in the nucleus of a cell undergoing necrosis or apoptosis), shrunken and eosinophilic cytoplasm with cytoplasmic vacuoles and loss of granules.
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==Respiratory System==
==Respiratory System==
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===Pneumonia===
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Although pneumonia is relatively uncommon in hamsters, it can be caused by a number of bacterial pathogens including ''Streptococcus pneumoniae, S. agalactiae, Pasturella pneumotropica, Staphylococcus aureus, Klebsiella pneumoniae, Bordetella spp, Corynebacterium paulometabulum'' and ''Salmonella spp.''.
Although pneumonia is relatively uncommon in hamsters, it can be caused by a number of bacterial pathogens including ''Streptococcus pneumoniae, S. agalactiae, Pasturella pneumotropica, Staphylococcus aureus, Klebsiella pneumoniae, Bordetella spp, Corynebacterium paulometabulum'' and ''Salmonella spp.''.
==Cardiovascular System==
==Cardiovascular System==
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===Atrial Thrombosis===
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Atrial thrombosis and congestive heart failure are associated with older female hamsters and occur frequently. Atrial thrombosis is also associated with amyloidosis (see above). Clinical symptoms include dyspnea, tachycardia and cyanosis.
Atrial thrombosis and congestive heart failure are associated with older female hamsters and occur frequently. Atrial thrombosis is also associated with amyloidosis (see above). Clinical symptoms include dyspnea, tachycardia and cyanosis.
Macroscopic pathology will display a thrombi most commonly in the left atria.
Macroscopic pathology will display a thrombi most commonly in the left atria.
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==Digestive System==
==Digestive System==
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Microscopic histopathology will include hyperplasia of the crypt epithelial cells, migration of immature epithelium into the villi, downward extension of the crypts through the lamina propria, muscularis mucosa, submucosa, Peyer's patches, muscularis externa and serosa. There will be necrosis of epithelial cells to a varying degree with haemorrhage, pyogranulomatous inflammation and crypt microabcesses.
Microscopic histopathology will include hyperplasia of the crypt epithelial cells, migration of immature epithelium into the villi, downward extension of the crypts through the lamina propria, muscularis mucosa, submucosa, Peyer's patches, muscularis externa and serosa. There will be necrosis of epithelial cells to a varying degree with haemorrhage, pyogranulomatous inflammation and crypt microabcesses.
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===Infectious Causes of Enteritis===
===Infectious Causes of Enteritis===
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Macroscopic pathology is widespread and includes enterocolitis with oedema,hyperemia of the large intestines, lymphadenitis and multifocal liver necrosis.
Macroscopic pathology is widespread and includes enterocolitis with oedema,hyperemia of the large intestines, lymphadenitis and multifocal liver necrosis.
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===GI Parasites===
===GI Parasites===
'''Nematodes (Pinworms)'''
'''Nematodes (Pinworms)'''
Macroscopic pathology will show thickened and inflamed intestines.
Macroscopic pathology will show thickened and inflamed intestines.
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==Musculoskeletal System==
==Musculoskeletal System==
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==Other==
==Other==
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