The MADISPREAD project aims at generating underpinning knowledge on the keystone of MDV entry and shedding and at defining its interaction with and replication in differentiated cells from the hematopoetic and from the skin epithelium lineages. Reduction of the contamination of the environment is also addressed through the design of 4th generation vaccines that would improve biosecurity by providing protection against clinical disease and shedding if infectious wild-type virus. The novelty of the project is to adapt the last achievements and most recent tools in cell differentiation biology and molecular virology to study virus entry in and shedding by differentiated cells and generate more efficient vaccines. The expected results will essentially concern generic knowledge on: (i) Avian cell differentiation with an emphasis on skin and lymphoid lineages, (ii) Type-specific cellular determinants controlling MDV spread and shedding, (iii) Vaccines that control shedding and entry of pathogenic MDV strains.