Abstract
A simplified procedure for obtaining high levels of infective, metacyclic trypomastigotes of a Brazilian strain of Trypanosoma cruzi in vitro is described. Epimastigotes cultured in Yaeger's Liver Infusion Tryptose Medium, when transferred to Grace's Insect Tissue Culture Medium (GMA) supplemented with 10% foetal bovine serum, yielded over 90% metacyclic forms. Decreasing or eliminating the serum from GMA adversely affected growth but did not decrease levels of transformation, thus providing a chemically defined culture system for analysing factors influencing metacyclogenesis of T. cruzi.