Changes

Avian Encephalomyelitis (AE) is commonly known as epidemic tremor in chickens and is caused by a hepatovirus [[avian encephalomyelitis-like virus 1| '''''avian encephalomyelitis-like virus 1''''']] (AEV).  The disease is of economic concern to breeders and layers as it causes a decrease in egg production in laying hens and causes neurological diseases in chicks under three weeks of age.

Avian Encephalomyelitis (AE) is commonly known as epidemic tremor in chickens and is caused by a hepatovirus [[avian encephalomyelitis-like virus 1| '''''avian encephalomyelitis-like virus 1''''']] (AEV).  The disease is of economic concern to breeders and layers as it causes a decrease in egg production in laying hens and causes neurological diseases in chicks under three weeks of age.

The disease is spread commonly via the '''horizontal''', faecal-oral route and chicks from non-immune layers under the age of three weeks are neurologically affected.  '''Vertical transmission''' can also occur from infected layer to their chicks.  The virus may be shed for several weeks and cause a decrease in egg hatchability. Once a bird becomes infected with the disease or is vaccinated it is immune to AE for life as there is only one serotype for the AEV. Some birds however can become blind.  AE is not considered a zoonosis.

The disease is spread commonly via the '''horizontal''', faecal-oral route and chicks from non-immune layers under the age of three weeks are neurologically affected.  '''Vertical transmission''' can also occur from infected layer to their chicks.  The virus may be shed for several weeks and cause a decrease in egg hatchability. Once a bird becomes infected with the disease or is vaccinated it is immune to AE for life, some birds are left blind.  AE is not considered a zoonosis.

==Signalment==

==Signalment==

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'''.

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 <ref name="Shafren, 1992">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.</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 antibodiesas because there is only one serotype for the AEV.  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 <ref name="Shafren, 1992">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.</ref>