Figure 5: Freeze dry section of a leech, twenty-four hours after infective blood feeding with Trypanosoma evansi. In the coelomic cavity, several trypanosomes can be seen assembled in the anterior region of the leech, close to the proboscis (arrows). Some parasites were attached to the proboscis sheath wall (arrowheads) and inside of the proboscis sheath (circles). In the proboscis, they were located in the thick middle layer composed of muscle cells, most of them as rounded forms (squares) (1000 X).