The Behavior of the Virus of Equine Encephalomyelitis on the Chorioallantoic Membrane of the Developing Chick

Abstract

Both the western and the eastern strains of equine en-cephalomyelitis may be cultivated upon the chorio-allantoic membranes of the developing chick. Also, virus inoculated upon the membranes of the egg may be recovered from the nerve tissues and from the amniotic fluid of the embryo after a definite time interval. This migration could be followed by a typical growth curve, terminated by death of the embryo. The virus was also recovered from the pooled heart blood of several embryos, suggesting a portal of entry by way of the blood stream. Because of the lethal effect of the virus upon the embryo, the inoculation of the developing egg can successfully be utilized both for titrating the potency of the virus and for carrying out the in vitro neutralization test.