Pseudorabies virus is an acute, frequently fatal disease with a worldwide distribution that affects swine primarily, and other domestic and wild animals incidentally. Pseudorabies virus has emerged as a significant pathogen in the USA since the 1960s, primarily due to the increase in confinement swine. Clinical signs in nonporcine animals are similar to those of rabies, hence the name “mad itch”. Pseudorabies is a reportable disease and has been successfully eradicated from the vast majority of the USA.
The virus can be transmitted via nose-to-nose or fecal-oral contact. Indirect transmission commonly occurs via inhalation of the aerosolized virus. Infectious virus can persist for up to 7 hr in air.
Respiratory infection is usually asymptomatic in pigs more than 2 months old. The virus infects piglets to the most devastating effect, with mortality rates near 100% for individuals under one-month-old. Symptoms may include: