Immunization of ducks for type C botulism

A single subcutaneous immunization with a vaccine used for protecting ranch mink (Mustela vison) against type C botulism reduced morbidity and mortali ty in mallard (Anas platyrhynchos) and northern pintail (Anas acuta) ducks challenged with approximately 4.5 x 10(4) and 2.25 x 10(4) mouse lethal dos es (MLD50), respectively of botulinum toxin at 10 and 15 days post-immuniza tion (pi). There was no significant protection at 5 days pi. Protection per sisted in mallards for 90 days pi. To simulate use of vaccine as a part of treatment of sick birds in die field, mallards were exposed to toxin and, w hen clinical signs were evident, each bird was treated by intraperitoneal i njection of type C botulinum antitoxin and one-half of the birds were immun ized. Immunization had no significant effect on recovery from intoxication. At 10 days post treatment, all birds were challenged with toxin. Clinical signs and mortality were significantly less frequent among immunized birds than among non-immunized birds after the second exposure. Immunization migh t be useful as part of the treatment regimen in botulism outbreaks.