RESUMO
To understand epidemiological characteristics of Marek's disease virus (MDV) prevalent in china currently,3 Marek's disease (MD) strains were isolated and identified from white feather meat chickens vaccined with MDV CVI988 or 814 through necropsy,histopathological observation,virus isolation and IFA detection,named SDAU1501,SDAU1502 and SDAU1503,respectively.vIL8,pp38,MEQ gene of the three strains of MDV were amplified using PCR,and compared with reference strains.The homology between SDAU1501 and SDAU1502 and virulent strains was above 97％,suggesting some features of virulent strains;while meq gene of SDAU1503 lost P amino acid at the 194 th site as that in CVI988,But the distinctive 177 nucleotide insertion mutations was not existed,predicting that it may be a attenuated vaccine strain.New variations of MDV continued and different types of variants emerged,therefore,prevalence and genetic monitoring of MD should be proceeded;meanwhile,more attentions should be given to MDV vaccine development.