Measurements of Strains of Trypanosoma Congolense

Abstract

The question whether Trypanosoma dimorphon is a species distinct from T. congolense has been reopened by Hoare (I959)· He examined, and measured the trypanosomes in, the original slides of Laveran and Mesnil which were the type material for establishing T. dimorphon as a distinct species. He found that the length of the trypanosomes ranged from II to 24, u, and that the mean lengths varied from I 5· 3 to I7· 6, u.(These measurements were made in slides from four mice, four rats and two goats.) In the strains of T. congolense recorded by Hoare, the length of the trypanosomes ranged from 8 to I9· 5, u and the mean lengths varied from I2" 3 to If· f, u. He states that'The means of each of these species form a continuous group, without a real break in the variation of length between the respective strains and/or samples, but there is a definite gap between the highest mean of the shorter species (I4· 4, u) and the lowest mean of the longer one (I5· 3, u).'He concluded that'As the result of the present revision, the differential diagnosis of T. dimorphon is so well defined that it should now be removed from the synonymy of T. congolense and restored to its original status as an independent species.'He admitted, however, that the occurrence of strains with intermediate mensural characters could not be excluded, and that if their existence were confirmed it might be necessary to reduce the rank of T. dimorphon and other congolense-like strains to some minor taxon.