A PATHOGENIC CHALLENGE MODEL FOR ADULT NORTHERN BOBWHITE (COLINUS-VIRGINIANUS) USING A VACCINE STRAIN OF PASTEURELLA-MULTOCIDA TYPE-3

A pathogenic challenge model causing approximately 50% mortality was d eveloped in adult Northern bobwhite (Colinus virginianus) using Avicho l(R), a live vaccine containing the Clemson University (CU) strain of Pasteurella multocida Type 3. A dose of 2300 or 3000 colony-forming un its (CFU) of Avichol(R) injected intramuscularly resulted in 30 to 75% mortality, whereas a dose of 230 CFU or less resulted in no mortality , and 58,720 CFU or more resulted in death in all birds challenged. Pr imary and secondary vaccination of Northern bobwhite with a formaliniz ed anaculture of Avichol(R)-derived P. multocida resulted in protectio n against challenge in three separate experiments. Dexamethasone treat ment of birds during vaccination resulted in decreased protection agai nst challenge exposure.