Figure 4.

Decreased pathology in the spleen and lungs corresponds to increased survival. Pathology scores ranging from 0 to 4 were assigned to the lung and spleen sections from each group of four animals collected at 5 days after challenge. Results of clinical scoring of brain tissue are not shown because no changes were observed. Groups of animals that were protected by vaccination in the survival experiment are designated by (+), partially protected by (±) and groups not protected by (−). Bars represent the mean of each group and error bars indicate s.e.m. Kruskal–Wallis analysis with a Dunn’s post test was performed, and significance is represented by asterisks (*P⩽0.05, **P⩽0.01 and ***P⩽0.001). Black asterisks denote significance between vaccinated groups and DMEM controls, and grey asterisks represent differences between the vaccinated groups and vector controls. The scoring criteria were as follows: 0=no lesions; 1=focal to few multifocal mild lesions; 2=multiple multifocal mild-to-moderate lesions; 3=multifocal areas of moderate-to-severe lesions; and 4=extensive areas of lesions and necrosis.