EXPERIMENTS ON THE EPIDEMIOLOGY OF PSEUDORABIES : I. MODE OF TRANSMISSION OF THE DISEASE IN SWINE AND THEIR POSSIBLE RÔLE IN ITS SPREAD TO CATTLE

Pseudorabies is a very fatal but non-contagious disease in cattle and the common laboratory animals. It is a relatively mild yet highly contagious disease in swine. It has been shown that in swine the nose serves both for the entrance and the exit of the virus. Furthermore, it has been observed that fatal pseudorabies infections in rabbits can be induced merely by bringing their abraded skin into contact with the noses of infected swine. The blood sera of swine on two farms where pseudorabies had occurred among the cattle were found to be capable of neutralizing pseudorabies virus. It is believed that in these instances the swine had a mild and unrecognized pseudorabies infection and transmitted their disease to the cattle with which they were associated, by transfer of the virus on their noses to the abraded skin of the cattle.