Comparative immunogenicity of two bivalent botulinum vaccines

Objective To compare the ability of a new single-dose botulinum vaccine con taining a non-mineral oil adjuvant with a single dose of a conventional bot ulinum vaccine product to produce antibody to Clostridium botulinum types C and D in cattle in Northern Australia. Design and procedure One hundred and fifty Brahman steer weaners were rando mly divided into two groups receiving either a single dose of CSL Bivalent Botulinum vaccine or Websters Singvac. Blood samples were collected at 0, 8 and 24 weeks and tested by antibody ELISA. The final samples were also tes ted by the toxin neutralisation test, to test titres of neutralising antibo dy. Results Six months after inoculation, cattle vaccinated with Websters Singv ac had ELISA antibody response twice that of CSL conventional product. Howe ver, this difference was only evident for neutralising antibody to type C b otulinum toxin. Both products produced similar titres of type D neutralisin g antibody after a single dose. Conclusion Websters' Singvac produces a greater neutralising antibody respo nse to type C botulism upon single inoculation than a conventional vaccine. The product produces an equivalent neutralising antibody response to type D.