Boars may play a significant role in dissemination of PPV at a critical time. During acute infection the virus is shed by various routes, including semen, and the isolation of PPV from semen of naturally infected boars has been reported. Semen may be contaminated externally, as for example with viruscontaining feces, or within the male reproductive tract. The virus was isolated from a testicle of a boar 5 days after it was injected into the boar's prepuce and from testicles of boars killed 5 and 8 days after they were infected oronasally (Mengeling, unpublished data 1976). Virus was also isolated from scrotal lymph nodes of boars killed 5, 8, 15, 21, and 35 days after oronasal exposure. After day 8, isolation was accomplished by cocultivating lymph node fragments with fetal porcine kidney cells (Mengeling, unpublished data 1976). Irrespective of their immune status, boars can also function as a vehicle for mechanical dissemination of PPV among susceptible females.