Avian Encephalomyelitis

Avian encephalomyelitis (AE), or epidemic tremor, is a worldwide infectious viral disease affecting the central nervous system of young birds (during the first 2 weeks) such as chickens, turkeys, quail, pheasants, and pigeons, causing ataxia and rapid tremors with milder clinical signs in turkeys than in chickens. AE virus, belonging to the genus Tremovirus of the family Picornaviridae, is enterotropic and can be transmitted horizontally and/or vertically. In layers and breeders, the virus caused a drop in egg production and reduced hatchability. The diagnosis depends on the clinical signs, histopathological lesions of the brain, pancreas, and duodenum, and PCR. The virus can be isolated in 6-day-old embryonated chicken eggs. One vaccination of breeder hens before egg production with inactivated or live vaccines prevents disease in breeders and progeny. Commercial ELISA is available for monitoring vaccination status.