Assessment of the pathogenicity of

Introduction: Material and Methods: Goslings were divided into three groups and either infected with the goose isolate MG-GD01/22, infected with chicken-derived MG R(low) or left untreated as controls. Clinical scores were recorded, and morbidity/mortality, air-sac lesions and tracheal and lung histopathology evaluated. Isolate membrane proteins were separated by SDS-PAGE and screened by Western blot with goose hyper-immune sera. Results: Both MG-GD01/22 and MG R(low) established infection, with morbidity rates of 90% and 80% and qPCR positivity of 100% and 80%, respectively. The MG-GD01/22 isolate caused 20% mortality and more severe respiratory signs, whereas MG R(low) induced milder disease without deaths. Both strains produced airsacculitis and interstitial pneumonia, but MG-GD01/22 caused more marked pulmonary haemorrhage. Gel electrophoresis showed similar bands at 50-130 kDa with differences at 25-50 kDa. Western blot revealed strong immune responses to conserved 75 kDa and 67 kDa proteins, particularly those of MG-GD01/22. Conclusion: Both strains are pathogenic in geese, with MG-GD01/22 exhibiting higher virulence. The conserved 75 kDa and 67 kDa proteins represent promising targets for the development of diagnostic assays and vaccines against