The Effect of Low Temperature on the Spirochetes of Relapsing Fever

Abstract

A simple method has been developed for the preservation of the spirochetes of relapsing fever at low temp. Samples of rat blood containing Spirochaeta novyi, S. obermeieri, S. duttoni, and S. kochi, obtained 48 hrs. after inoculation, remained infective for mice following 27 months of storage at [long dash]48[degree] C. in a specially constructed "deep-freeze" obtained from Motor Products Corporation, North Chicago, Illinois. The stage of the disease during which the infected blood was obtained was the most important factor in determining the survival of the organisms. However, the number of organisms present in the specimens also appeared to be significant in limiting the period of time any sample would retain its infectivity.