Cultivation of Toxoplasma in the Developing Chick Embryo. ∗

Abstract

Summary

A laboratory-adapted strain of toxoplasma was successfully propagated in the embryonated hen's egg. Uniform mortality was obtained and the majority of deaths occurred between Sand 6 days after inoculation. The concentration of organisms in the chick embryo gave LD₅₀ titers of 10^-4.5 to 10^-5.0 which approximated that usually attained in mice. Repeated passage through eggs resulted in no modification of pathogenicity for animals.