The life cycle of Trypanosoma chrysemydis

Abstract

Trypanosoma chrysemydis of Chrysemys picta marginata reached the infective stage in 22 days in the crop and caeca of Placobdella parasitica and P. rugosa kept at 22–24 °C; this period was shortened to 14 days at 31 °C. Metacyclic stages were found in the crop. Leeches deprived of food for prolonged periods lost infections. Metacyclic forms reverted to epimastigotes and started to divide in leeches given a second blood meal. Leeches in nature probably retain infections throughout their lives if they get regular blood meals.Painted (Chrysemys picta marginata), snapping (Chelydra serpentina), and map (Graptemys geographica) turtles were infected by inoculation of metacyclic forms from leeches or cultures, and by bites of infected leeches. Turtles that ate infected leeches did not become infected. Amphibians could not be infected. The number of trypanosomes in the peripheral blood of naturally infected turtles was always low and only low parasitaemias were found in experimentally infected turtles, apparently because this trypanosome rarely divides in the vertebrate host.