Protection efficacies of four rough ST-based LI vaccines. All the immunized and control mice groups were challenged with 106.9TCID50 LI strains at week 8 post-immunization. Protection shown by a cocktail of all the four strains. The protection against LI was assessed based on the presence of gDNA in stool samples. Protection is presented as the number of animals showing gDNA in stool samples to the total number of animals in that group. Five animals were sacrificed at each time-point indicated.