Fluorescent Antibody Reactions in Trypanosoma rhodesiense and T. gambiense in Experimental Animals

Abstract

A fluorescent anti-body technique for the serodiagnosis of African trypanosomiasis in experimental animals is described. The indirect fluorescent antibody test employing the trypanosome form from rats as antigen appears to be highly sensitive to rabbits infected with T. rhodesiense and T. gambiense. Results of 29 sera from rabbits infected with T. rhodesiense organisms yielded 29 positive reactions, whereas 21 positive reactions and one weak reaction were obtained from 22 rabbits infected with T. gambiense organisms. The reproducibility of this test employing different lots of trypanosomes and labeled antiglobulin was good. Animals were inoculated with varying doses from 4 x 104 to 5 x 106 trypanosomes and were bled at weekly intervals. Antibodies were detected between 1 and 2 weeks after inoculation with no apparent correlation between the early appearance of antibodies and the size of the inoculum as previously reported with helminthic infections. The similarity of observable reactions between the African trypanosomes and T. lewisi as antigen is of great interest. Since T. lewisi is non-pathogenic for humans and can be maintained readily in most laboratories, it is of great importance in areas where sufficient precautions cannot be taken to prevent human infections.