Fig. (4) Survival of Dutch-belted rabbits treated with 14.3 mg/kg/day of levofloxacin beginning at various times after challenge with 100 LD50B. anthracis Ames spores by nasal instillation. Levofloxacin was given for 13 days following the challenge of each group. Groups that initiated treatment at 24 and 48 h, were significant beginning at day 3, however, the 48 h group was only significant until day 7, while the 24 h group was significant through the end of the study. All other groups were not significant. Significance from the control was determined by the Fisher Exact Test (p<0.05).