Chick Embryo Mortality Studies Using Different Strains of Mycoplasma Gallisepticum

Four M. gallisepticum strains isolated from cases of chronic respiratory diseases (CRD) were studied and compared with MG-S6 and MG-F strains for their pathogenic potential for embryonated chicken eggs. The embryo mortality was found to be dose dependent. However, all four strains with few exceptions, caused 100% embryo mortality, showing that apart from the virulence factor the bulk multiplication may also result in embryo death. Amongst the four strains used MI-211 was found to be the most pathogenic one. The present investigation indicates that the pathogenicity of MI-211 is comparable with that of MG-S6 which is reported to be highly pathogenic.