The present invention relates inter alia to attenuated live parasites of the phylum Apicomplexa and the family of Trypanosomatidae and to the use of such attenuated live parasites in a vaccine and in the manufacturing of such a vaccine. Furthermore, the present invention relates to vaccines comprising such attenuated live parasites and to methods for the production of such vaccines. Finally, the invention relates to specific tet-repressor fusion proteins and to attenuated live parasites according to the invention comprising such tet-repressor fusion proteins.
