TABLE 2.
K-D-K-E mutant viruses are attenuated in mice compared to wild-type WNVa
| Inoculum | Dose (PFU) | Morbidity (no. sick/total) | Mortality (no. dead/ total) | AST (SD)b | Infection rate (no. infected/ total)c |
|---|---|---|---|---|---|
| Diluent | NA | 0/4 | 0/4 | NA | 0/4 |
| WNV NS5 K61A | 10 | 0/8 | 0/8 | NA | 1/8 |
| WNV NS5 K61A | 103 | 0/8 | 0/8 | NA | 8/8 |
| WNV NS5 K61A | 105 | 3/8 | 0/8 | NA | 8/8 |
| WNV NS5 K182A | 10 | 0/8 | 0/8 | NA | 6/8 |
| WNV NS5 K182A | 103 | 0/8 | 0/8 | NA | 8/8 |
| WNV NS5 K182A | 105 | 0/8 | 0/8 | NA | 8/8 |
| WNV wild type | 10 | 7/8 | 5/8 | 10.6 (1.9) | 5/8 |
| WNV wild type | 103 | 8/8 | 4/8 | 10.3 (1.3) | 8/8 |
| WNV wild type | 105 | 8/8 | 7/8 | 9.0 (1.2) | 8/8 |
a
Six-week old C3H female mice were inoculated s.c. in the left rear footpad and monitored for weight loss and clinical signs. NA, not applicable.
b
AST, average survival time (in days) calculated for mice that died only.
c
Surviving mice were bled on day 28 postinoculation and tested for WNV-specific antibody by enzyme-linked immunosorbent assay. Positive WNV infection was defined as either seropositivity or death consistent with WNV disease.