Intradermal vaccination for Mycoplasma hyopneumoniae

Abstract

Objectives: To evaluate the ability of needleless intradermal (ID) vaccines to induce protection against clinical disease and to compare the serological response of pigs to intramuscular (IM) and ID vaccination with Mycoplasma hyopneumoniae bacterins. Materials and methods: In each study, pigs seronegative for M hyopneumoniae were vaccinated either once or twice with M hyo-pneumoniae bacterins. The serological response to ID and IM vaccination was evaluated by the DAKO M hyopneumoniae blocking ELISA, and ID vaccine efficacy was tested by experimental respiratory challenge with a heterologous strain of virulent M hyopneumoniae. Results: Injection site reactions were minimal for all vaccines. Pigs vaccinated ID, either by needle or needleless injector, had significantly higher M hyopneumoniae antibody titers than did pigs vaccinated by IM injection. Pigs vaccinated by needleless ID injection had lower lung lesion scores and higher IgA and IgG titers in bronchoalveolar lavage fluid than did nonvaccinates following challenge. Protective immunity was established by 21 days postvaccination after a single ID dose of vaccine. Intradermal vaccination of swine for M hyopneumoniae by needleless injector was safe and efficacious, and did not require shaving or other preparation of the skin. Implications: Intradermal vaccination of swine with needleless injectors is feasible if vaccines are formulated for small doses (eg, 0.2 mL).