TYPE-C BOTULISM IN TURKEYS - DETERMINATION OF THE MEDIAN TOXIC DOSE

The median toxic dose (TD50) of type C botulinum in turkeys was determ ined using an up-and-down method for toxicologic testing. Birds were d osed intravenously with 10, 20, or 40 mouse lethal dose per kilogram b ody weight (MLD/kg) of type C botulism toxin and observed for 5 days. Administration of toxin resulted in acute death, posterior paresis, or no effect, depending upon the dose. The TD50 causing posterior paresi s was calculated as 25.75 MLD/kg (confidence interval = 17.08-38.82 ML D/kg). Posterior paresis was identified as the principal sign associat ed with sublethal botulism toxicosis in turkeys. The resultant posteri or paresis was similar to the clinical syndrome observed in an unsolve d field investigation.