Avian Encephalomyelitis (AE), is also known as Epidemic Tremor. AE is mainly transmitted through eggs, although horizontal transmission can occur between infected chicks and susceptible chicks or mature birds. Young chicks (1 to 4 weeks) exhibit symptoms such as ataxia, incoordination, paralysis, or rapid tremors of head and neck, while adult birds have decreased egg production1. Antibodies to avian viruses in serum can be detected by the Enzyme Linked Immunosorbant Assay (ELISA). The levels of AEV antibodies in serum, as well as the immune status of entire flocks can be monitored using ELISA. 

Inactivated antigen is bound to a microwell. Diluted sera is added to the microwell and incubated. Any anti-AEV antibodies present in the serum will bind to the AEV on the microwell forming an AEV antigen-antibody complex. After washing away any unbound material, anti-Chicken IgG Alkaline Phosphatase conjugate is added to the microwell. The conjugate will bind to the AEV antigen-antibody complex. After incubation any unbound conjugate is removed by washing. Enzyme substrate is then added to the microwell. The substrate reacts with any Alkaline Phosphatase present and forms a yellow product. In the final step the reaction is stopped, fixing the color. The intensity of the color is measured photometrically at 405 - 410 nm.