Vaccinator device for delivering propellant-driven aerosols of Streptococcus suis bacterin into the respiratory tracts of swine.

Metered-dose propellant-driven small particle aerosols of a killed whole bacterium, Streptococcus suis, were produced and characterized for their aerodynamic particle sizes and antigenicity as potential respiratory mucosal vaccines against S. suis infections in swine. To facilitate the efficient delivery of such vaccine aerosols to large animals, an electro-mechanical device was developed to synchronize aerosol release to an animal's inhalation cycles. The device was tested for its capacity to deliver a fluorescein conjugate of this bacterin (FITC-S. suis) into the respiratory tracts of 18 pigs. Results showed that FITC-S. suis could be detected in the lungs of swine as small as 4.5 kg with as few as two aerosol actuations. Metered-dose propellant-driven aerosols of bacterin vaccines delivered by this respiratory vaccinating device are discussed as a new approach for stimulated mucosal immunity against respiratory infections in animals.