Pseudorabies virus (PRV) is an enveloped, double-stranded, DNA virus approximately 140 kb in length classified into the the genus Varicellovirus, subfamily Alphaherpesvirinae, family Herpesviridae. PRV is the causative agent of Aujeszky’s disease (AD) or mad itch. First recorded in 1813 in cattle in the United States, PRV has been observed to infect a wide variety of animal species including swine, ruminants, carnivores, rodents, and lagomorphs. In all species excluding pigs, PRV infection causes acute, severe disease, characterized by insatiable itching, and is always lethal.
In swine, PRV causes neurological, respiratory, and reproductive disease. Morbidity and mortality rates are higher in suckling and weaning pigs. Respiratory and reproductive disorders are more often observed in adult pigs. AD is an economically important swine disease that has spread globally. Strict control efforts have largely eradicated AD in parts of Europe and North America (including the United States). Presently, AD remains endemic in areas of high swine populations in eastern and southeastern Europe, Latin America, Africa, and Asia.