Determination of the mouse lethal dose of rNY1682-E158G. Six-week-old female BALB/cJ mice (n = 10/group) were inoculated intranasally with 50 μl containing 1 × 102, 1 × 103, 1 × 104, or 1 × 105 TCID50 of rNY1682-E158G or mock inoculated. (A) Morbidity was assessed by weight changes over a 14-day period, and it is graphed as a percentage of the weight on the day of inoculation (day 0). The average body weight of each group is shown, with error bars representing SD. (B) Mortality of the mice was also monitored for 14 days postinoculation.