Efficacy of a Commercial Bacterin in Protecting Strain 13 Guinea Pigs against Bordetella bronchiseptica Pneumonia.

A commercial Bordetella bronchiseptica bacterin that does not contain adjuvant was evaluated in strain 13N guinea pigs for efficiency against an airborne challenge of virulent B. bronchiseptica. Vaccinated animals developed humoral antibody titers that ranged from 128 to 1024, as measured by ELISA. When challenged with 325 median lethal doses LD50 of B. bronchiseptica in a small particle aerosol, the vaccinated guinea pigs were fully protected from lethal effects. Only minimal acute tracheitis with mild multifocal lymphatic hyperplasia occurred in the vaccinated, challenged animals. However, the induced immune response did not completely eliminate the challenge organisms within the 30-day observation period. Sham-vaccinated guinea pigs, on the other hand, died of a fulminant bronchopneumonia within 6 days following aerosol challenge. The commercial bacterin, therefore, provided protection against a massive airborne challenge, and prevented the inducement of significant pathological alterations.