Cross-sections of Trypanosoma brucei gambiense purified from infected rat blood by chromatography on DEAE cellulose column and incubation in secretion medium (A, B, C) and directly after cardiac puncture of infected rat (D, E, F). A-C: parasites purified from secretion medium; D-F: parasites purified directly from infected rat blood. A-F: Free vesicles and budding of new vesicles at the coated plasma membrane surface of the parasite, high magnification of vesicle formation (B), budding vesicles at the flagellum (semi-longitudinal section) (C). f flagellum, k kinetoplast, m mitochondrion, n nucleus, pm plasma membrane with surface coat, pmt pellicular microtubules, v vesicle. Scale bars A, D, E 200 nm, B, C, F 100 nm.