Intranasal Immunization of Dogs Against Bordetella bronchiseptica-Induced Tracheobronchitis (Kennel Cough) with Modified Live-Bordetella bronchiseptica Vaccine

Abstract

SUMMARY The efficacy of an intranasally administered live- Bordetella bronchiseptica strain 55 (S-55) vaccine for the prevention of B bronchiseptica-induced canine infectious tracheobronchitis (kennel cough) was assessed in two experiments. In the first experiment, 20 vaccinated and 11 control dogs were challenge exposed (14 days after vaccination) with virulent B bronchiseptica strain D-2 (aerosol). Frequency of clinical tracheobronchitis, blood serum agglutination titer to B bronchiseptica and suppression of growth of D-2 organisms in the upper respiratory tract by S-55 vaccine were determined. The vaccination with live S-55 significantly ( P ≤ 0.001) reduced the occurrence of clinical tracheobronchitis by 95%. One of the 20 S-55 vaccinated dogs and 11 of the 11 control dogs had clinical tracheobronchitis. Coughing in S-55 vaccinated dogs and in control dogs lasted 0.15 and 9.73 days, respectively. There was significant ( P ≤ 0.001) suppression of D-2 challenge organisms in the vaccinated dogs. At postchallenge day 28, S-55-vaccinated dogs and control dogs averaged 5.52 × 10 3 organisms and 2.56 × 10 6 D-2 organisms in each milliliter of nasal secretions, respectively. At 28 days after dogs were challenge exposed to D-2 aerosol, the serum agglutination titers in vaccinated and control dogs averaged 1:43 and 1:349, respectively. In the second experiment, five S-55-vaccinated and five control dogs were challenge exposed (14 days after vaccination) with D-2 and examined for presence of clinical tracheobronchitis, pulmonic lesions, and excessive tracheal mucus. None of the five vaccinated dogs and 5 of the 5 control dogs had clinical tracheobronchitis and pulmonic lesions from which challenge B bronchiseptica organisms were recovered. Excessive mucus was found in tracheas of none of the vaccinated dogs and in all of the control dogs.