Infection establishment of different T.b.brucei strains in G.m.morsitans tsetse flies.

(A) Tsetse saliva deposits containing metacyclic trypanosomes of the T.b.brucei AnTAR1, AnTat1.1E^dsRed or AnTat1.1E^TagGFP2 strains. Microphotographs are merged brightfield and fluorescence images of saliva deposited on pre-warmed glass slides by SG+ flies infected with the respective parasite strains. (B) Flow cytometric analysis of salivary gland outflows containing AnTAR1, AnTat1.1E^dsRed or AnTat1.1E^TagGFP2 metacyclic trypanosomes. Fluorescent populations are indicated in the appropriate gates. Histogram insets illustrate the dsRed and TagGFP2 fluorescence in the AnTat1.1E transgenic metacyclics in comparison with the non-tagged AnTAR1 population (dotted line). (C) Trypanosome numbers in the outflows of non-disrupted salivary gland pairs from individual flies (n = 5 /group) infected with one of the three different parasite strains. These differences in parasite density in the salivary glands between the wildtype and the reporter strains were also clear by microscopical inspection in eight independent experiments for the comparison T.b.brucei AnTAR1 (total n = 1666 flies) vs. AnTat1.1E^dsRed (n = 2091) and two independent experiments for the comparison T.b.brucei AnTAR1 (n = 245) vs. AnTat1.1E^TagGFP2 (n = 228). Parasite numbers in the salivary glands were analysed by flow cytometry. * P < 0.05