Experimental infections by
Trypanosoma (Megatrypanum) minasense were
performed in primates -
Saimiri sciureus and
Callithrix penicillata - with the
objective of searching for morphological variations of the blood trypomastigotes with respect
to hosts and time of infection. We carried out morphological and morphometric analysis of
blood trypomastigotes. Illustrations are given.
Both the squirrel monkey and marmoset became infected after the injection of blood
trypomastigotes of
T. minasense , although the parasitaemia were briefer in the
squirrel monkey. The parasites detected in the later host were narrower and shorter than
those found in the inoculated marmoset. In the marmoset, the blood stream parasites derived
from culture metacyclic trypomastigotes were considerably smaller than those derived from
the inoculation of infected blood.
Stronger evidence of polymorphism was found when, at the same time of infection, the
blood trypomastigotes found in squirrel monkey had smaller length, body width and the
distance from posterior end of the body to the kinetoplast almost four times smaller than the
parasite found in the marmoset. Therefore, conflicting results on morphology and
morphometry of
T. minasense obtained by previous investigators could be due to
polymorphism.
