Fig. 2

Overview of the current status on tsetse paratransgenesis. Strategies have been developed for i) isolation and in vitro cultivation of Sodalis glossinidius, ii) establishing stable chromosomal expression in Sodalis allowing strong and constitutive expression of anti-trypanosome compounds in the absence of antibiotic selection and iii) the sustainable colonization of tsetse fly and its subsequent generations with genetically modified Sodalis through microinjection of the bacterium into third-instar larvae [109; this issue]. Taken together, the necessary technology for application of Sodalis as a delivery system in tsetse paratransgenic has been developed, but the Sodalis-mediated inhibition of parasite development in the insect host is yet to be demonstrated. The final main bottleneck remains the identification of a highly potent and stable trypanolytic component effectively blocking parasite transmission by the fly without impairing symbiont and vector fitness