Quantitative methods in the study of trypanosomes and their applications: With special reference to diagnosis.

In the first part of this paper the author summarizes and discusses previous quantitative work on trypanosomes, with particular reference to biometrical studies, in vivo and in vitro studies on numbers of trypanosomes, studies on hosts infected with trypanosomes, and physiological studies.The second part discusses recent work done at the East African Trypanosomiasis Research Organization. A method for the measurement of the infectivity of trypanosome suspensions, based on serial dilution and inoculation into test animals, is outlined, and applications likely to improve diagnostic procedures are suggested for it. Such applications might include: the establishment of experimental procedures not significantly reducing the infectivity of trypanosomes under experiment; determination of the effects on the infectivity of preserved material of some of the factors in the process of preservation, important for the preparation of standard material; comparison of the efficiency of different culture media for the isolation of trypanosomes; study of the distribution of trypanosomes in the vertebrate host; and measurement of the susceptibility of trypanosomes to drugs. The author stresses the importance of relating future experimental work with trypanosomes to preserved material for which comprehensive documentation is available.