Preliminary note on the cultivation of Green's distemperoid virus in fertile hen eggs

Abstract

Green's distemper vaccine virus has been propagated 30 generations in developing hen eggs. Injections were made onto the chorio-allantoic membranes of eggs that had received a preliminary incubation of 8 days. Re-incubation was done at 35°C., and passage of the membranes was made at approximately 4 day intervals. The egg-adapted strain produced markedly oedematous changes with some necrosis in the membranes, but only occasionally killed the embryo. The titre of infected chorio-allantoic membranes, measured by ferret injection was between 10⁻³ and 10⁻⁵. That of the embryos and extra-enbryonic fluids of the same eggs was 10⁻³. The reactions produced by the egg-adapted strain when injected into ferrets were similar to those produced by the parent strain. Five c.c. of anti-distemper serum neutralized the egg-cultured virus. Thirteen dogs were inoculated with suspensions of chorio-allantoic membranes. In nine there was no reaction. In one there was a slight reaction, but in three the reactions were very severe and one died after showing typical distemper symptoms. The egg-adapted virus did not agglutinate chicken or guinea pig red cells and failed to infect mice when instilled intra-nasally.