Studies on Macroschizonts of Theileria parva

Abstract

A series of measurements was made of the schizonts of Theileria parva in the hope that these criteria might be used in the differential diagnosis of the theilerial species. Macroschizonts were found to have an average size of 4.8 μ, which was smaller than expected. They contained from 1 to 85 nuclei, with an average of 8. In autopsy smears there were from 4 to 760 schizonts per thousand lymphocytes, with an average of 264. The degree of parasitosis at death was not correlated with the duration of illness. A plea is made for the use of the terms ‘macroschizonts’ and ‘microschizonts’ in place of the more traditional ‘agamonts’ and ‘gamonts’.