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==Introduction==

==Introduction==

Hamsters are now commonly used in laboratory testing, but for many years other species including mice, rats and guinea pigs were used for studies requiring small easily managed animals. In 1919 the first study using hamsters was undertaken assessing the susceptibility of Chinese hamsters to ''leishmania''. A number of difficulties were encountered including an inability to breed the animals and hamsters were not used again until the 1930s when a Syrian hamster burrow was uncovered by an archaeologist near Aleppo. Nearly all common golden hamster breeds are related to these wild discovered hamsters. Syrian hamsters ''(Mesocricetus auratus)''were used and were found to be easier to breed and had more desirable traits for laboratory testing than Chinese hamsters. Syrian hamsters have gone on to become the most commonly encountered laboratory hamster species with around 500,000 per year currently used in the US. However, approximately ten times more mice and rats are used compared to hamsters.

Hamsters are now commonly used in laboratory testing, but for many years other species including mice, rats and guinea pigs were used for studies requiring small easily managed animals. In 1919 the first study using hamsters was undertaken assessing the susceptibility of Chinese hamsters to ''leishmania''. A number of difficulties were encountered including an inability to breed the animals and hamsters were not used again until the 1930s when a Syrian hamster burrow was uncovered by an archaeologist near Aleppo. Nearly all common golden hamster breeds are related to these wild discovered hamsters. Syrian hamsters ''(Mesocricetus auratus)''were used and were found to be easier to breed and had more desirable traits for laboratory testing than Chinese hamsters. Syrian hamsters have gone on to become the most commonly encountered laboratory hamster species with around 500,000 per year currently used in the US. However, approximately ten times more mice and rats are used compared to hamsters.

===Cholangiofibrosis===

===Cholangiofibrosis===

Also called cholangiohepatitis, the cause of this pathology is thought to be from a Helicobacter species called ''H. cholecysticus''. Affected hamsters display no clinical signs.

Also called cholangiohepatitis, the cause of this pathology is thought to be from a [[Helicobacter|Helicobacter]] species called ''H. cholecysticus''. Affected hamsters display no clinical signs.

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Macroscopic pathology includes bile duct hyperplasia, pericholangial fibrosis and centrilobular pancreatitis.

Macroscopic pathology includes bile duct hyperplasia, pericholangial fibrosis and centrilobular pancreatitis.

A common route of infection of LCM in research laboratories is via the transplantation of LCM-containing tumours. Macroscopic pathology may include splenomegally, swollen or shrunken pitted kidneys and hepatomegally. Microscopic pathology may include lymphocytic meningitis, chronic glomerulonephropathy, widespread vasculitis and widespread lymphocytic infiltration.

A common route of infection of LCM in research laboratories is via the transplantation of LCM-containing tumours. Macroscopic pathology may include splenomegally, swollen or shrunken pitted kidneys and hepatomegally. Microscopic pathology may include lymphocytic meningitis, chronic glomerulonephropathy, widespread vasculitis and widespread lymphocytic infiltration.

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