TABLE 1.
Pathogenicity and virus titer of parental and YLMY motif tyrosine residue mutant viruses
| Virus | Pathogenicity |
Virus titer |
||
|---|---|---|---|---|
| MDT (h)a | ICPI scoreb | Log10 ELD50/ml | Log10 TCID50/ml | |
| rSG10* | 60.0 | 1.50 | 8.63 | 7.88 |
| rSG10*-FY524A | 57.6 | 1.61 | 8.56 | 7.95 |
| rSG10*-FY527A | 50.4 | 1.71 | 9.17 | 8.50 |
| rSG10*-FYY524 + 527AA | 57.6 | 1.58 | 9.17 | 8.00 |
a
Mean death time (MDT) is the mean time for the minimum lethal dose of virus to kill all inoculated embryos. Pathotype: virulent strains, <60 h; intermediate virulent strains, 60 to 90 h; avirulent strains, >90 h.
b
Intracerebral pathogenicity index (ICPI): velogenic strains,1.5–2.0; moderately virulent strains, 0.7–1.5; avirulent strains, 0.0 to 0.7. ELD50, median embryo lethal dose; TCID50, tissue culture infective dose.