Trypanosoma cruzi Epimastigogenesis: A Method for Studying Trypomastigote to Epimastigote Transformation In Vivo

Abstract

Trypanosoma cruzi epimastigogenesis naturally occurs in the intestine of the invertebrate host. It is not known whether the morphological changes that occur during transformation of bloodstream trypomastigotes to epimastigotes are identical for different T. cruzi isolates. This research shows a useful method for studying the events that occur during epimastigogenesis, comparing parasites from epidemiological sources. Rhodnius prolixus V stage nymphs were fed artificially with an ad hoc solution containing blood-like trypomastigotes and the morphological changes were examined during eight days. Anterior intestinal contents were removed by decapitation and squeezing the abdomen of the nymphs, which permitted obtaining quickly almost 100% of the inoculate with loads between 1.9 and 8.9 × 106 trypomastigotes/nymph. The number of parasites per nymph and morphological changes were determined using phase microscopy with Giemsa staining. The nymphs ingested 7.4 times their weight of the infecting solution with volumes between 101 e 357 μL (229 ± 66 mg); 50% of the ingest was eliminated as urine during the first 24 hours. The trypomastigotes transformed to rounded forms before evolving into epimastigotes following different kinetics according to the isolate. This method is proposed for rapid, quantitative study of the early events of epimastigogenesis for T. cruzi in vivo.

Keywords

• Trypanosoma cruzi
• epimastigogénesis in vitro e in vivo
• Rhodnius prolixus