EN
Marek’s disease (MD) is a lymphoproliferative disease of poultry caused by a cell-associated herpesvirus called Marek’s disease virus (MDV). The disease has a significant economic impact on the poultry industry. MD is the first oncogenic disease controlled by vaccination. Live vaccines are administered either to one-day old chicks or to 18-day old embryos. However, although MD vaccines target MDV replication in the cytolic phase and prevent lymphoma development, they do not prevent infection and replication of pathogenic strains of MDV. One of the important problems is an evolution toward greater virulence and the emergence of vvMDV and vv+MDV strains. The development of novel vaccines is necessary. DNA vaccines based on entire viral genomes cloned as bacterial artificial chromosomes (BAC) are considered. The genetic incorporation into recombinant vaccines of genes for immunomodulatory stimuli or vaccines from deletion mutants prepared from virulent MDV strains lacking vIL8 and gene meq are also under consideration.