The Growth and Distribution of Murine Encephalomyelitis Virus in the Developing Chick Embryo

Abstract

The FA strain of Theil-er''s mouse encephalomyelitis virus was grown in 6-day-old fertile eggs of the hen and carried through 9 generations. Incubation was done at 35 [degree]-35.6 [degree]C before, as well as after, inoculation. The humidity was 85[degree]-87[degree]. The original inoculum was made by grinding infected mouse brain with sterile alundum in cold, sterile dist. water to make a 10% suspension. This was centrifuged and 0.1 ml. of the super-nate was placed on the dropped chorio-allantoic membrane. The shell opening and the hole over the natural air sac were sealed. The eggs were harvested 5-10 days later and the harvests consisted of allantoic fluids, amniotic fluid, chorio-allantoic membrane, chick embryo brain, and the corpus minus the central nervous system. When supernates from suspensions of these materials were tested intracerebrally in mice, the virus was found to be distributed irregularly throughout the egg. The greatest conc. was in the corpus minus the central nervous system, and the least was in the brain. The virus was also present in the yolk sac.