Effect of dosage and vaccination route on transmission of a live attenuated Mycoplasma gallisepticum vaccine: a broiler model.

Abstract

Mycoplasma gallisepticum (MG) is an economically significant pathogen of poultry species. Among the table egg sector of the poultry industry, live attenuated strains of MG are commonly used to limit production losses associated with MG-induced disease. These vaccines, however, may be problematic to broiler- and turkey-related industries because of associated virulence; therefore, an understanding of the transmissibility of the live MG vaccines is of particular importance. In the present study, a broiler model addresses the effect of vaccine application route and dosage on the transmission of the MG vaccine FVAX-MG to commingled unvaccinated subjects for 7 wk postvaccination. Vaccinations occurred at 2 wk of age via eyedrop or spray application at 1 x (4 x 10(6) colony-forming units [cfu]), 10(-3) x (4 x 10(3) cfu), or 10(-6) x (4 cfu) of the manufacturer's recommended dosage, and subsequent transmission to unvaccinated subjects was measured. The serologic response to MG antigen and the presence of MG DNA indicated FVAX-MG transmission only within the 1 x FVAX-MG eyedrop treatment. Among no other treatment was transmission of FVAX-MG detected. The results of the present study demonstrate that the dosage and vaccination route may have direct implications on subsequent transmission of FVAX-MG.