title: Pathogenicity of two strains of Mycoplasma gallisepticum in broilers.
abstract: Strains F and R of Mycoplasma gallisepticum (MG) were compared in two laboratory trials for their relative pathogenicity in terms of inducing airsacculitis and antibody production to MG. Chickens exposed to the R strain had significantly higher incidence of air-sac lesions (P less than 0.05) and greater severity of airsacculitis than did chicks exposed to the F strain. In both trials, chickens vaccinated simultaneously with Newcastle disease-infectious bronchitis vaccine and exposed to MG had more severe lesions than did chickens exposed to mycoplasma alone. chickens exposed to the F strain had significantly lower geometric mean hemagglutination-inhibition antibody titers to MG than did chicks exposed to the R strain. Chickens vaccinated simultaneously with Newcastle disease-infectious bronchitis vaccine and exposed to R strain had significantly lower body weights than did chickens in the other group.
mesh_terms: D000400:Air Sacs; D000818:Animals; D000907:Antibodies, Bacterial / Q000032:analysis; D000914:Antibodies, Viral / Q000032:analysis; D002645:Chickens / Q000276:immunology; D001351:Infectious bronchitis virus / Q000276:immunology; D009174:Mycoplasma / Q000276:immunology; D009175:Mycoplasma Infections / Q000209:etiology / Q000276:immunology / Q000662:veterinary*; D009522:Newcastle disease virus / Q000276:immunology; D011201:Poultry Diseases / Q000209:etiology* / Q000276:immunology; D014765:Viral Vaccines / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D000914:Antibodies, Viral; D014765:Viral Vaccines