Mycoplasma gallisepticum is the primary etiologic agent responsible for chronic respiratory disease in chickens and infectious sinusitis in turkeys resulting in substantial economic losses to poultry producers throughout the world.

The failure or limited protection of previous and current M. gallisepticum vaccines can be explained by the fact that little is known regarding the virulence determinants of this pathogen. "Attenuations” of these modified live vaccines have not been defined at the molecular level. In order to speed-up the research Center of Excellence of Vaccine Research, University of Connecticut, supported by United States Department of Agriculture (USDA), launched in Spring of 2000 the “M. gallisepticum genome project” using DNA from the virulent R strain. This project was specifically aimed at discovering the genetic basis of its virulence in order to target genes for vaccine development and improve diagnostic means.