TKT and cerebellar ataxia: However, on the third day after inoculation, mice in the rBartha-K61 group showed neurological symptoms, such as catch bar and ataxia, and the survival rate dropped to 0 at 4 days after inoculation (Figure 5A), indicating that due to the deletion of the TK gene, the virulence of Bartha-K61 strain was weakened and its pathogenicity to mice was reduced, and the recombinant virus had lower virulence.