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Tyzzer's disease is an acute, highly fatal bacterial infection that is seen in a wide range of animals. It most commonly affects foals and laboratory animals and occasionally dogs, cats and calves. Tyzzer's disease in foals usually occurs in individual animals, whereas outbreaks of disease occur in rodents and [[Tyzzer's Disease - Rabbit|rabbits]]. The disease most commonly affects young, stressed animals.  

Tyzzer's disease is an acute, highly fatal bacterial infection that is seen in a wide range of animals. It most commonly affects foals and laboratory animals and occasionally dogs, cats and calves. Tyzzer's disease in foals usually occurs in individual animals, whereas outbreaks of disease occur in rodents and [[Tyzzer's Disease - Rabbit|rabbits]]. The disease most commonly affects young, stressed animals.  

The bacteria that causes the disease is ''[[Clostridium piliforme]]'', a gram negative spore-forming intracellular bacterium found in soil and faeces. The aetiology of the disease is poorly understood. Infection most likely results from oral exposure to spores; possible mechanisms include ingestion of spore-forming faeces or contact with carrier animals. Following ingestion, the spores colonise the intestine and liver via the portal circulation. Dissemination to the hepatocytes, enterocytes and myocytes then occurs.

''Clostridium piliforme'' is a gram negative spore-forming filamentous intracellular bacterium found in soil and faeces. The colonies only grow in tissue culture or embryonated eggs. The disease is  characterised by severe hepatic necrosis. It has an incubation period up to 1 week.

 

The aetiology of the disease is poorly understood. Infection most likely results from oral exposure to spores; possible mechanisms include ingestion of spore-forming faeces or contact with carrier animals. Following ingestion, the spores colonise the intestine and liver via the portal circulation. Dissemination to the hepatocytes, enterocytes and myocytes then occurs.

==Clinical signs==

==Clinical Signs==

The disease in rabbits and rodents is usually characterised by an unkempt coat, depression and fatal diarrhoea. Foals are usually aged between one and six weeks of age and are often clinically normal at birth. Rapidly progressive clinical signs relating to an acute hepatitis then develop. Clinical signs include acute lethargy, loss of suckle reflex, severe icterus, neurological signs (such as head pressing or circling), pyrexia and diarrhoea. Animals may be found dead without known pre-existing clinical signs. The course of the disease from the onset of clinical signs to death is usually around 48 hours.  

The disease in rabbits and rodents is usually characterised by an unkempt coat, depression and fatal diarrhoea. Foals are usually aged between one and six weeks of age and are often clinically normal at birth. Rapidly progressive clinical signs relating to an acute hepatitis then develop. Clinical signs include acute lethargy, loss of suckle reflex, severe icterus, neurological signs (such as head pressing or circling), pyrexia and diarrhoea. Animals may be found dead without known pre-existing clinical signs. The course of the disease from the onset of clinical signs to death is usually around 48 hours.  

'''Ultrasound''' of affected animals may show a grossly enlarged liver with rounded edges.  

'''Ultrasound''' of affected animals may show a grossly enlarged liver with rounded edges.  

Definitive diagnosis relies either on observation of intracellular bacteria at the periphery of liver lesions or on '''bacterial culture'''. Giemsa stain is used to visualise the bacteria which are seen as intrahepatocellular filamentous rods.  

Definitive diagnosis relies either on observation of intracellular bacteria at the periphery of liver lesions or on '''bacterial culture'''. Giemsa stain is used to visualise the bacteria which are seen as intrahepatocellular filamentous rods. Diagnosis can also be achieved by Warthin-Starry silver impregnation technique demonstrating the organisms in hepatocytes.

Laboratory diagnostic tests are of little value in small mammals as death is usually rapid. Recently, a PCR test has been described for use in these animals but this is not currently commercially available.  

Laboratory diagnostic tests are of little value in small mammals as death is usually rapid. Recently, a PCR test has been described for use in these animals but this is not currently commercially available.  

<big>'''Also see [[Tyzzer's Disease - Rabbit]].'''</big>

<big>'''Also see [[Tyzzer's Disease - Rabbit]].'''</big>

==References==

==References==

 

[[Category:Hepatitis,_Bacterial]][[Category:Rodent - Alimentary System]][[Category:Liver Diseases - Horse]]

[[Category:Hepatitis,_Bacterial]][[Category:Rodents]][[Category:Alimentary_Disorders_-_Horse]]

[[Category:Expert_Review]]

 

[[Category:Expert_Review]][[Category:To_Do_-_SophieIgnarski]]

[[Category:Cattle]]