Laboratory Experiments with Living Newcastle Disease Vaccine

Abstract

VARIOUS attempts to produce a practical and effective killed vaccine for Newcastle disease having failed in our hands, attention was devoted to the development of a live virus vaccine of the type reported by Iyer and Dobson (1940), Brandly and his colleagues (1946) and more recently by Komarov and Goldsmit (1946), Van Roekel, et al. (1948), all of whom found this kind of vaccine to be a safe and efficient immunizing agent. In view of the successful modification by Komarov and Goldsmit of a Middle-Eastern strain of Newcastle disease virus by brain to brain passage in ducklings, it was decided to attempt serial passage in duck embryos as a means of attenuating American strains. The present report describes the method of preparing and testing a live virus vaccine containing a modified strain of virus derived in this manner. Komarov and Goldsmit (1947) have subsequently reported the attenuation of the Haifa . . .