Changes

Grossly, lymphocytic infiltration of the muscular region of the ventriculus has also been noted as well as perivascular infiltration within the brain and chord, with the exception of the cerebellum, where lesions can be found only in the nucleus cerebellaris.  Pathognomonic lesions can be found within the midbrain and rotundua and ovidalis nucleus  (microglisosis) and proventriculus (dense nodules within the muscular wall).  Lesions can also be present in the pancreas.  

Grossly, lymphocytic infiltration of the muscular region of the ventriculus has also been noted as well as perivascular infiltration within the brain and chord, with the exception of the cerebellum, where lesions can be found only in the nucleus cerebellaris.  Pathognomonic lesions can be found within the midbrain and rotundua and ovidalis nucleus  (microglisosis) and proventriculus (dense nodules within the muscular wall).  Lesions can also be present in the pancreas.  

'''Differential diagnosis''': include [[Newcastle Disease Virus| Newcastle disease (ND)]], [[Equine Viral Encephalitis| Equine encephalomyelitis infection]], nutritional disturbances (rickets, encephalomalacia, riboflavin deficiency), and Marek’s disease  Calnek, B.W.(2003). Avian Encephalomyelitis. In: Saif, Y.M., Barnes, H.J., Glisson, J.R., Fadly, A.M., McDougald, L.R., Swayne, D.E., eds. Diseases of Poultry. Ames, Iowa, USA: Iowa State Press, 271-282.

'''Differential diagnosis''': include [[Newcastle Disease Virus| Newcastle disease (ND)]], [[Equine Viral Encephalitis| Equine encephalomyelitis infection]], nutritional disturbances ([[Rickets| rickets]], encephalomalacia, riboflavin deficiency), and [[Mareks Disease| Marek’s disease]] <ref name="Calnek, 2003"Calnek, B.W.(2003). Avian Encephalomyelitis. In: Saif, Y.M., Barnes, H.J., Glisson, J.R., Fadly, A.M., McDougald, L.R., Swayne, D.E., eds. Diseases of Poultry. Ames, Iowa, USA: Iowa State Press, 271-282.</ref>

==Distribution==

==Distribution==

Worldwide, the disease has been documented in Africa, Asia, Australia, Europe, and North and South America.

Worldwide, the disease has been documented in Africa, Asia, Australia, Europe, and North and South America.

==Treatment==

==Treatment==

There is no treatment for chicks infected with avian encephalomyelitis (AE). Affected chicks that that survive are considered unlikely to be profitable (Calnek, 2003). Surviving chicks will be immune to AE for life.

There is no treatment for chicks infected with avian encephalomyelitis (AE). Affected chicks that that survive are considered unlikely to be profitable <ref name="Calnek, 2003" />. Surviving chicks will be immune to AE for life.

==Control==

==Control==

In regions where AE is prevalent an effective way of preventing AE is to vaccinate pullets several weeks before they come into lay.  Vaccination protects the flock from a reduction in egg production and prevents vertical transmission of the virus to chicks by providing the chicks with a sufficient level of maternal derived antibodies.  There are live and attenuated vaccinations available which can be administered in drinking water or as an eye drop, the latter being more effective. vaccination by eye-drop of only 10% of a flock gave the same results as drinking water application Shafren, D.R., Tannock, G.A., Groves, P.J. (1992) Antibody responses to avian encephalomyelitis virus vaccines when administered by different routes. Australian Veterinary Journal, 69(11):272-275; 10 ref.

In regions where AE is prevalent an effective way of preventing AE is to vaccinate pullets several weeks before they come into lay.  Vaccination protects the flock from a reduction in egg production and prevents vertical transmission of the virus to chicks by providing the chicks with a sufficient level of maternal derived antibodies.  There are live and attenuated vaccinations available which can be administered in drinking water or as an eye drop, the latter being more effective. vaccination by eye-drop of only 10% of a flock gave the same results as drinking water application Shafren, D.R., Tannock, G.A., Groves, P.J. (1992) Antibody responses to avian encephalomyelitis virus vaccines when administered by different routes. Australian Veterinary Journal, 69(11):272-275; 10 ref.