Immunization of mice against Fusobacterium necrophorum infection by perenteral or oral administration of vaccine.

Immunization of mice against Fusobacterium necrophorum infection was attempted by using 3 vaccination procedures: (1) intraperitoneal (IP) injection of F necrophorum cells in saline solution, (2) IP injection of cells with added aluminum hydroxide adjuvant, and (3) feeding of a powdered mouse diet containing lyophilized cells. One or 2 weekly IP injections of the bacteria cells (in saline solution) for 3, 6, or 12 weeks resulted in protection of 48.7% to 64.5% of the mice against challenge exposure. Of the 2 control groups (given saline solution only), 100% and 97.4% became infected. Weekly IP injections of bacterial cells in an aluminum hydroxide adjuvant for 3, 6, or 12 weeks resulted in protectivity of 54.1% to 77.5%. Of the control mice (given adjuvant only), 97.5% became infected. Bacterial cells fed to mice at a dose level of 1.5 mg (dry weight)/g of powdered diet for 30 days (4 or 5g of diet each day) resulted in only a delay in the mean time of death as compared with the rapid death of the control mice. The feeding dose of 0.15 mg of cells/g of diet did not delay the mean time of death.