MECHANISMS OF TRANSMISSION OF AUJESZKYS-DISEASE VIRUS ORIGINATING FROM FERAL SWINE IN THE USA

To understand the possible mechanisms of transmission of Aujeszky's di sease virus (pseudorabies or PRV) from a feral pig reservoir, intranas al infections were initiated in domestic pigs and in pigs from a herd derived from captured feral pigs. Virus strains originating from feral pigs and from domestic pigs were compared. Similar shedding patterns were obtained in both feral-derived and domestic pigs, however, virus strains from feral pigs were markedly attenuated. Virus could be isola ted after acute infection from nasal secretions, tonsils and occasiona lly from genital organs. In studies of transmission of PRV by cannibal ism, either latently infected or acutely infected tissue was fed to bo th domestic and feral-derived pigs. In two similar experiments, latent ly infected tissue did not transmit virus, but tissues from acutely in fected pigs did transmit infection, Cannibalism was observed typically in both types of pigs older than 6 weeks of age. It was concluded tha t transmission of PRV originating from feral pigs can occur by several mechanisms including the respiratory route and by cannibalism of pigs that die of acute infection, Transmission of PRV from feral swine may , however, result in sub-clinical infection. (C) 1997 Elsevier Science B.V.