The Relative Importance of Certain Factors in the Low-Temperature Preservation of Malaria Parasites 1

Abstract

In a recent paper the senior author (1942) reported work dealing with the low-temperature preservation of malaria plasmodia, and showed that this was a potentially very useful technique with many advantages, some of which even a good method of cultivation would not have. In the first paper the previous work on the subject was also reviewed, and will therefore not be included in the present report. The investigation, of which this paper is an account, was an attempt to clear up some of the doubtful factors in the low-temperature preservation of malaria parasites. Among the factors studied were the relative advantages of thinner tubes, manual as compared with mechanical rotation, in the freezing and thawing process, freezing and storage temperatures, the effect of time of storage on viability, and the effect of a high proportion of parasitized cells on the proportion of parasites remaining viable after freezing and thawing.