Development of Vaccinia and Variola Viruses in Embryonated Eggs at 28°C

Abstract

Summary

Vaccinia and variola viruses were established and maintained on transfer in the chorioallantoic membrane of embry-onated eggs incubated at a temperature sufficiently low to prevent embryonic development (28°C). The number of elementary bodies present in the membrane on the 3rd day approximated that in eggs incubated at a temperature which favored growth of the embryo (37°C). At 28°C, however, the effect of the respective viruses on the membrane and the embryo as well as the cellular response of the former to them was significantly retarded.