The trypomastigote stage of Trypanosoma gambiense swims in the blood of its mammalian host.
This photo shows three trypomastigotes. The body shape is undulating, characteristic of many species of trypanosome. The nucleus is large and is located in the centre of the trypomastigote. The smaller, densely-staining kinetoplast is at one end. The flagellum and undulating membrane are clearly visible in all three specimens.