The testing of proven Trypanosoma brucei and T. rhodesiense strains by the blood incubation infectivity test.

The authors describe a simple test (the blood incubation infectivity test) by which Trypanosoma brucei (sensu stricto) may be differentiated from T. rhodesiense without recourse to human volunteers. The method consists in incubating the strain of trypanosome under test for 5 hours at 37 degrees C in vitro in human blood, followed by observation of the effect of this procedure on the strain's infectivity to rats.Thirteen strains of T. rhodesiense were investigated; in each, the ability to infect rats was retained after incubation. In all 6 strains of man-tested T. brucei, it was destroyed.The consistency of the results with proven strains suggests very strongly that the blood incubation infectivity test provides a valid means of differentiating these parasites.