Effect of trypanosome dose on intradermal infection.

(A) Parasitemia development in peripheral blood of mice (n = 5/group) naturally infected by the bites of T.b.brucei AnTAR1 (empty symbols) and T.b.brucei AnTat1.1EdsRed infected tsetse flies (filled symbols) with respectively a high and low number of parasites in the salivary glands. (B) Parasitemia progression in peripheral blood of mice (n = 3/group) intradermally inoculated with varying numbers of metacyclic parasites (200, 50, 20 and 5 MCF) extracted from SG+ G.m.morsitans tsetse flies versus 200 purified bloodstream (BSF) T.b.brucei parasites. These data are representative of 3 independent experiments. Infection rates are recorded following intradermal needle inoculation of varying numbers of (C) washed (round symbols) or DEAE52-purified (red squares) metacyclic (MCF) T.b.brucei parasites isolated from tsetse salivary glands (n = 3 or 6 for each parasite dose and experiment, totaling 48 mice) and (D) DEAE52-purified bloodstream (BSF) T.b.brucei parasites (n = 3 or 6 for each parasite dose and experiment, totaling 42 mice). The parasitological status was checked for 14 days following parasite inoculation. Different symbol colours indicate the 3 independent infection experiments. Different sizes of the symbols are to avoid overlaps. Red squares correspond to the BSF infection rates calculated from the infection experiment that also included the DEAE52-purified MCF parasites as shown in panel C. Data are shown as the mean ± SEM.