Efficacy of curing toxemic rabbits. Animals were intranasally infected with Vollum spores, and following the development of septicemia, the animals were treated for 14 days with doxycycline (A), ciprofloxacin (B), doxycycline and rabbit anti-PA antibodies (C), ciprofloxacin and rabbit anti-PA antibodies (D), or ciprofloxacin and monoclonal antibody number 29 (E). The results are expressed as individual serum PA levels prior to initiation of antibiotic administration.