Diagnosis of respiratory diseases among growing and finishing swine has become a challenge for food animal practitioners. The incidence and severity of respiratory disease has increased with confinement raising of hogs. Pseudorabies (Aujeszky's Disease. mad itch) caused by Herpesvirus suis. can affect pigs. dogs. cats, cattle, sheep, and goats. There have been no confirmed cases of pseudorabies in horses. Although invariably fatal in other species, pseudorabies virus infection in swine can cause a variety of clinical syndromes characterized by respiratory signs, central nervous system (CNS) symptoms, and reproductive failure. These syndromes vary according to route of infection, viral strain, immune status of the animal and most importantly, age of the pig at the time of infection.