Trypanosoma lewisi, T. acomys and T. cruzi: A method for their cultivation with mammalian tissue

Trypanosoma lewisi, T. acomys, and T. cruzi were grown in vitro at 37 C in culture media with mammalian cells. The trypanosomes and the host tissues cultured readily from infected animals (Lewis rats, mice, and Acomys cahirinus). The majority of T. lewisi grown at 37 C were trypomastigotes. Cultures of T. acomys at 37 C were predominantly epimastigotes with less than 10% of trypomastigote forms being present. Most of T. cruzi grown at 37 C were epimastigotes, but trypomastigotes and promastigotes were also present. Multiplication and survival of T. lewisi continued until the 37th day. T. acomys survived for 45 days and T. cruzi survived for at least 40 days, both showing a growth of millions over the starting inoculum. Subcultures of T. lewisi and T. acomys were successful only when the initial number of the parasites was more than 1-2 × 10⁶/ml. Infection in newborn Acomys (spiny-backed mouse) resulted from the injection of culture forms, and cultured T. lewisi caused fatal infections when injected into newborn rats.