Morphological and taxonomic studies on mammalian trypanosomes

Abstract

An account is given of the spontaneous occurrence in the Anglo-Egyptian Sudan of strains of the camel trypanosome, Trypanosoma evansi , devoid of kinetonuclei. These cases, of which four are recorded, were observed in widely separated localities within the enzootic area of camel trypanosomiasis. A critical review is given of the question of “akinetonucleate” trypanosomes in general—in strains produced experimentally and in those occurring spontaneously—with special reference to their mode of origin and their significance in the production of new races. The prevalence of “akinetonucleate” forms in normal strains of trypanosomes has been estimated in the case of a number of species and races hitherto not examined from this point of view, all the existing data being brought together in tabular form. While the factors causing the appearance of “akinetonucleate” individuals and strains under natural conditions could not be ascertained, irregular division of the trypanosomes is held to be mainly responsible for the elimination of the kinetonucleus and for the persistence of the aberrant condition.