Changes

===Pathology===

===Pathology===

Macroscopically, the hair coat is seen to be rough, body condition is poor and there is evidence of severe dehydration. Faecal staining may be suggestive of diarrhoea during life. The intestine itself is oedematous and petechial or ecchymotic haemorrhages may be seens on the serosal or mucosal surfaces of the jejunum and ileum. Thymic atrophy is apparent and the bone marrow is gelatinous or liquid in texture. Animals infected ''in utero'' or neonatally nay show gross hypoplasia of the cerebellum,

Macroscopically, the hair coat is seen to be rough, body condition is poor and there is evidence of severe dehydration. Faecal staining may be suggestive of diarrhoea during life. The intestine itself is oedematous and petechial or ecchymotic haemorrhages may be seens on the serosal or mucosal surfaces of the jejunum and ileum. Thymic atrophy is apparent, lymph nodes are pale and oedematous and the bone marrow is gelatinous or liquid in texture. Animals infected ''in utero'' or neonatally nay show gross hypoplasia of the cerebellum,

 

Histologically, the cells lining the intestinal crypts undergo complete necrosis and sloughing, but little inflammation is seen. The villi are shortened and blunted (villous atrophy)and fibrinous exudates may be seen on surface of the mucosa. There is an absence of lymphocytic infiltrates in all tissues and lymphoid depletion of lymph nodes, Peyer's patches and the spleen. Eosinophilic intranuclear inclusion bodies are formed during the early stages of infection, but these are usually not possible to observe on routine examination of sections. In neonatal and foetal infections, the granular and Purkinje cells of the cerebellum may be depleted.

The crypt lining cells undergo complete necrosis, but very little inflammation is seen.  

Fibrinous exudates may be seen on surface of the mucosa. However,the submucosa and lamina propria are often unaffected. Cyst-like structures are seen in the deepest parts of  the glands of the intestinal mucosa after only a few days of infection. These cystic glands are lined with flattened epithelial cells.

 

Inclusion bodies may also be seen, but these are often very hard to find.

 

The [[Lymph Nodes - Anatomy & Physiology|Lymph nodes]] appear pale and oedematous, and almost aplastic. The [[Bone Marrow - Anatomy & Physiology|Bone marrow]] appears pale and fatty looking and is depleted of cells.

==Treatment==

==Treatment==