DETECTION AND GENOMIC TYPING OF MAREKS-DISEASE VIRUS WITH POLYMERASE-CHAIN-REACTION

New pathogenic isolates of the Marek's disease virus type 1 (MDV1) wer e found in various Russian regions. The most variable region of the gl ycoprotein B (gB) gene was analyzed in 13 MDV strains and isolates and proved to be conserved. Pathogenic strains of MDV1 had two or three 1 32-nt inverted repeats, in contrast to nonpathogenic strains and MDV t ype 2 and 3. A highly sensitive complex method was elaborated for dete cting MDV and distinguishing between MDV types and the turkey herpesvi rus and between pathogenic (oncogenic) and nonpathogenic MDV strains. The method is based on PCR with primers to the gB and thymidine kinase genes and to the MDV inverted repeats.