Factors influencing variola virus growth on the chorioallantoic membrane of embryonated eggs.

The propagation of variola virus on the chlorioallantoic membrane of embryonated eggs was first reported by Torres and Teixeira (1935). Application of this finding was made by Lazarus et al. (1937), Buddingh (1938) and Markham and Bozalis (1939) who utilized embryonated eggs as a diagnostic medium. Nelson (1940, 1943), described the development and stability of variola virus in egg passage but gave only limited information regarding its multiplication on the chorioallantoic membrane. The paucity of data characterizing the propagation of variola virus prompted an investigation of its growth pattern on the chorioallantoic membrane of embryonated eggs and certain factors which influence viral multiplication.