F98 cells were cultured till 80–90% confluent (4–6 days) and exposed to a multiplicity of infection (m.o.i.)of 5 with recombinant BoHV-4 (BoHV-4EGFPΔTK) obtained by the insertion of an EGFP gene into the TK locus of the BoHV-4 genome [8], allowing rapid monitoring of the cell infection through EGFP expression. Here, TKT is linked to infection.