Skin virulence of attenuated pseudorabies virus (PRV) strains.

After intradermal inoculation of the attenuated pseudorabies virus (PRV) strains, Bartha, MK35 (gI+) and MK35-T-2 (gI-) to rabbits, they caused local inflammatory nodules with oedema reddiness and necrosis. The specifity of these reactions was confirmed by their inhibition with anti-PRV serum. The minimal dose that caused visible skin reaction was about 10(2) TCID50/ml for Bartha and MK35-T-2 (gI-) strains and over 10(4) TCID50/ml for the MK35 (gI+) strain. It is assumed that the established residual skin virulence can serve as an additional distinction marker for attenuated PRV strains.