Development and application of an improved infectivity assay for the standardization of avian encephalomyelitis vaccines

Avian encephalomyelitis: A review

“…Generally, non-egg-adapted strains of AEV do not induce gross signs of infection in susceptible embryos (Butterfield et al, 1969;Van Roekel et al, 1938;Hoekstra, 1964;Shafren & Tannock, 1990), although high titred strains may induce some mortality in embryonated eggs. Six to 7-day-old embryos inoculated with non egg-adapted strains by the yolk-sac exhibit clinical signs of the disease 1 to 9 days after hatching, indicating that virus multiplication occurs during embryogenesis (Hoekstra, 1964;Springer & Schmittle, 1968;Braune & Gentry, 1971;.…”

“…There have been further reports on the use of chicken embryo brain cell culture assays for the titration of AEV based upon the procedure, which confirm the findings of Berger (Hyde, 1986;Nicholas et al, 1986aNicholas et al, ,b, 1987. Shafren & Tannock (1990) reported the development of an egg infectivity assay in which endpoints were determined according to the presence of AEV antigen in specific-pathogen-free chicken embryo brains by an ELISA. This assay, which can be used for both egg-adapted and non-egg-adapted strains, is particularly useful for vaccine standardization.…”