The Survival of Toxoplasma gondii in Various Suspending Media

Abstract

Toxoplasma-in-fected mouse brains stored at 5[degree]C in neopeptone broth were still infective after 12 days, in some cases after 14-17 days, but the number of viable parasites was diminished as indicated by increased survival time of mice inoculated with them. Suspensions of toxoplasmas in saline, 1% broth, or 10% serum-saline were tested to determine viability of the parasites. Saline was the most unfavorable medium; even after 2 hrs. at room temp. inocula in saline lost some infectivity for mice. The addition of broth or serum resulted in a much more satisfactory suspending medium. Even after 4-5 hrs. at room temp., suspensions of toxoplasmas in these fluids remained 100% infective to mice. In some instances such suspensions retained their infectivity for 24 hrs.