1964 Volume 17 Issue 1 Pages 25-27
Toxoplasma (Tp) organisms and cysts were examined for resistance to high and low temperatures. The infected materials used were the liver and muscle of infected hogs collected from the Shibaura, Tokyo, Slaughterhouse, ascites of mice inoculated with Tp, and the brain harboring cysts of mice inoculated with the Beverley strain of Tp. They were kept at a certain temperature for a given time and then made to emulsion. The resulting emulsions were inoculated into mice and underwent several passages through mice. After that, ascites was collected from these mice and examined for the presence of Tp organisms.
As a result, the infectivity of Tp to mice was lost in natural materials kept at -10°C or below for a day. It was not damaged in the infected mouse brain harboring cysts and kept at-10°C for two days. It was maintained in both naturally and experimentally infected materials treated at 50°C for five minutes. It was destroyed, however, in these materials treated at 55°C for five minutes.
