Response of the Syrian Hamster to the Virus of Newcastle Disease after Three Hundred and Thirty Passages in this Mammal

Abstract

THE adaptation of the California strain of Newcastle disease virus No.11914 to the Syrian hamster through two hundred intracerebral passages has been reported (Reagen et al., 1948). This Newcastle virus has been passed through twenty-two successive series of ten to twelve day embryonated chicken eggs prior to hamster injection. Intracerebral passage in hamsters has been continued through three hundred thirty uninterrupted passages.The infected hamsters used for the passages were sacrificed while moribund. Suspensions were prepared by grinding the infected brain tissue in a mortar with alundum and diluting with physiological saline. The inoculum for the first fifty successive passages was approximately 0.08 cc. of a 10 percent (10−1) suspension, for the fifty-first to the one hundred twentieth passage 0.03 cc. of the suspension of the same concentration was used, and after the one hundred fiftieth passage each hamster was inoculated with 0.03 cc. of a 1 percent (10−2) suspension, …