Survival of Rickettsia prowazeki in Different Diluents.

At the present time very little information is available about the survival of typhus rickettsiae in fluid media. Data on this point are of value, however, in the solution of a number of problems which arise. The data presented in this report were not collected with the idea of making a detailed investigation of various media but simply to assess the value of media in common use for work in experimental typhus. Most of the data available in the literature are of very limited value in a comparative way. Topping (1940) has reported that skim milk, used as the suspending medium, prolonged the survival of rickettsiae of several species when preserved in the dried state. He also has recommended its use in work on the toxin (confidential report). Other authors have reported that rickettsiae will survive for varied periods of time in different media. (Laigret and Durand, 1933; Medical Research Council, 1930.)