A revision of Trypanosoma (Schizotrypanum) cruzi strains from British Honduras, and the importance of strain characteristics in experimental chemotherapy of Chagas's disease

Abstract

The characteristics of 10 strains of Trypanosoma cruzi from British Honduras are reviewed and discussed. The strains were isolated from the faeces of wild-caught Triatoma dimidiata and all proved to be highly pathogenic to white mice and rats and to certain species of wild rodents. All the strains were characterized by a high cardiotropism, which did not diminish even after prolonged passage in further animals. A variable degree of neurotropism, characterized by paralysis of the limbs, produced by the strains was observed in many laboratory animals as well as in some of the experimentally infected wild rodents. Histological studies of organs from several of the paralysed animals failed to provide definitive clues as to the origin of the paralysis. A wide range of dimorphism was observed in the blood-forms of T. cruzi from each of the isolated strains; this dimorphism and the mean nuclear index number changed during each passage. The morphogenesis of the parasites in tissues, in the insect vector, and in NNN culture medium, was found to include amastigote, sphaeromastigote, epimastigote and transitional trypomastigote forms, all leading to the formation of the infective trypanosome form. The importance of co-ordinated studies on the biological and physiological characteristics of T. cruzi strains from man, animal reservoirs, and triatomine insect vectors, from the regions where Chagas's disease is endemic, is emphasized as one of the fundamental requirements for the experimental chemotherapy of Chagas's disease.