Spontaneous shedding of pseudorabies virus from a clinically recovered postparturient sow.

Pseudorabies virus was shed by a sow that had been clinically infected 19 months earlier (when 1 month old) and had been in isolation for 3 1/2 months. The shedding was detected from the third to eighth days after farrowing and was confined to the nasal secretion. Two susceptible pigs in contact with the sow after farrowing were not infected.