Spray Application of Live Attenuated Mycoplasma Gallisepticum Vaccines06 January 2014
Both of the Mycoplasma gallisepticum live attenuated vaccines tested in pullets in this work in Mississippi were equally effective when applied by spray application. The researchers remarked that the dosages required for a consistent response were higher than the manufacturers' recommendations.
Live attenuated vaccines (LAV) are commonly used to protect commercial table egg producers from economic losses associated with challenges by the respiratory pathogen Mycoplasma gallisepticum (MG).
In a paper in Journal of Applied Poultry Research, Jeff Evans of the USDA-Agricultural Research Service in Mississippi State and co-authors there and at Mississippi State University explain that currently, four MG LAV are commercially available within the United States.
Consistent among vaccines, protection afforded by the MG LAV is contingent upon successful application and manufacturer recommended means of application may vary by product. They include vaccination via drinking water, spray and eye drop.
Due to producer preferences, the associated recommended vaccination route may reduce LAV applicability at an individual poultry facility.
To investigate the effect of an alternative vaccination route on vaccine efficacy, two MG-distinct LAV, which are considered to be of common origin yet differ in their respective recommended application routes (drinking water versus spray), were both applied to egg layer-type pullets via spray application.
Vaccine efficacies were assessed following application of varying doses (0, 1/100, 1/10, 1× and 10×) of each MG LAV and determining the corresponding post-vaccinal immunological responses, LAV-derived in vivo populations and protection against virulent MG challenge.
When applied by spray application, both MG LAV resulted in comparable immune responses, viable LAV-derived in vivo populations and protection against virulent MG challenge.
Evans and co-authors observed that dosage rates beyond those recommended by the manufacturers of both LAV were necessary for consistent effects under the conditions of the experiment.
Evans J.D., R. Jacob, S.A. Leigh, S.D. Collier, E.D. Peebles and S.L. Branton. 2013. Spray application of live attenuated F strain-derived Mycoplasma gallisepticum vaccines. J. Appl. Poult. Res. 22(4):842-848. doi: 10.3382/japr.2013-00749