Pathogenicity of two strains of Mycoplasma gallisepticum in turkeys.

Strains F and R of Mycoplasma gallisepticum (MG) were compared for their pathogenicity in broad-breasted white turkey poults in terms of induction of airsacculitis, depression of growth rate, and induction of antibody production against MG. Eye-drop inoculation with the F or R strain produced only minimal lesions. However, aerosol exposure with either MG strain resulted in a significantly higher incidence and severity of air-sac lesions (P less than 0.001), reduction of growth rate (P less than 0.005), and hemagglutination-inhibition (HI) antibody titers against MG than did eye-drop inoculation. There were no significant differences between the two MG strains in effects on incidence of air-sac lesions or on growth rate.