Studies on the Deposition, Migration, and Development to the Blood Forms of Trypanosomes Belonging to the Trypanosoma Brucei Group

Abstract

In a previous paper (Gordon, Crewe and Willett, 1956), we showed that the tsetse ejects saliva, and with it any contained metacyclic trypanosomesj during the whole process of probing the host's tissues, and that the saliva and therefore any contained trypanosomes-is widely distributed throughout a hemispherical area, the limits of which are represented by the range of the labium of the feeding fly, though the saliva probably seeps beyond them. In addition, it was shown that when an adequate blood-supply is tapped the tsetse feeds with the labium, and therefore with the contained hypopharynx, in close apposition to the rent in a torn capillary, and that, since the fly ejects saliva at frequent intervals whilst taking up its meal from an outpouring stream of blood, it is inevitable that some of this saliva and its contained metacyclic trypanosomes must enter directly into the circulation. It is with the subsequent fate of these trypanosomes, deposited respectively in the tissues and in the general circulation, that the present paper is concerned.