A–Time course of parasitemia after infection (mean value ± SEM, n = 6, per day); trypanosomes appear in the blood 6 days (D6) later, corresponding to stage 1 human African trypanosomiasis (HAT); successive parasitemic waves take place; abscissae: days after infection; ordinates: parasitemia/mL. B—Immunofluorescent staining of T. b. brucei (in red, white arrow) in the brain parenchyma on D16 post-infection, corresponding to stage 2 of HAT (section S5, subfornical organ of the hypothalamus, n = 3), bregma -3.14 mm (according to reference [25]); C—Hypothalamic cell nuclei stained with DAPI (blue, subfornical organ of the hypothalamus); T. b. brucei are also stained (white arrows); D—Sagittal schema of the brain (lateral 0.4 mm / (according to reference [25]) showing the position of the 5th coronal section (S5) chosen for iNOS immunostaining; E and F—Coronal schemas at bregma -3.14 mm (according to reference[25]) showing ventral (E) and dorsal (F) diencephalon. Grey matter, containing all brain cell types, was examined; G—Cellular labelling at section S5, bregma -3.14 using specific biological markers: neurons (NeuN), astrocytes (GFAP) and microglia (integrin alpha M) were identified (left column of part G); the 3 types of cells were also iNOS-positive (medial column of part G); double labelling appears in the right column (Neurons: NeuN and iNOS; Astrocytes: GFAP and iNOS; Microglia: Integrin alpha M and iNOS). Abbreviations: T. b. brucei, Trypanosoma brucei brucei; DAPI, 4’, 6’ Di amino-2-phenylindole; DNA, deoxyribonucleic acid; scale is given in μm, micrometer; NeuN, neuronal specific nuclear protein in vertebrates; GFAP, glial fibrillary acidic protein; Pe, periventricular hypothalamic n; PVP, paraventricular thalamic n, posterior part; SOR, supraoptic n, retrochiasmatic; An Olympus BX51 microscope was equipped with DP50 camera (objective 64x10).