Morphological and Taxonomic Studies on Mammalian Trypanosomes: III. Spontaneous Occurrence of Strains of Trypanosoma Evansi Devoid of the Kinetonucleus

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 akinetonuclea 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. © 1937, Marine Biological Association of the United Kingdom. All rights reserved.