A Comparative Study of Protective Immunity Provided by Oral, Intranasal and Parenteral Canine Bordetella bronchiseptica Vaccines

The present study was designed to determine if an oral live Bordetella bronchiseptica vaccine protects dogs from developing signs of respiratory disease after challenge with virulent Bordetella bronchiseptica. The study was also designed to compare the level of protection induced by the oral vaccine with the protection provided by an intranasal live vaccine and an injected killed vaccine. Forty 6-8 week old beagles, culture and antibody negative to Bordetella bronchiseptica, were randomly distributed to 4 groups. Group 1 (O) received a single dose of attenuated oral Bordetella vaccine at study day 14; Group 2 (IN) received a single dose of attenuated intranasal Bordetella vaccine at study day 14; Group 3 (SCu) received two doses of killed Bordetella vaccine administered subcutaneously at study days 0 and 14; and Group 4 (C) received saline both intranasally and subcutaneously. All dogs were challenged with virulent Bordetella bronchiseptica via nebulization chamber at study day 42. Blood and nasal swabs were collected weekly thru-out the study for serology and bacterial culture. After challenge, daily clinical assessments included body temperature and a weighted score of coughing and other respiratory disease signs. Severe signs of disease in the control group proved the validity of our challenge model. Results of this study showed that the oral Bordetella bronchiseptica vaccine protects dogs from challenge. This protection provided by the oral vaccine was equivalent to that induced by intranasal vaccine, and was superior to protection provided by the killed, subcutaneously administered vaccine.