Avian encephalomyelitis virus
Avian encephalomyelitis virus (AEV), a picornavirus, is the etiological agent of "Epidemic tremor", a neurological disease of young chicks. AEV is found worldwide. It was first discovered in the New England region of the United States in 1930.
Transmission: AEV is spread vertically and horizontally. Infected adult chickens are often subclinical carriers, showing no signs of disease other than reduced egg production in laying hens, and appearance of clinical signs in infected progeny.