Submitted to: Swine Disease Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: November 10, 1995
Publication Date: N/A
Technical Abstract: Porcine reproductive and respiratory syndrome (PRRS) is a virus-induced disease of swine which was first recognized during the late 1980's. The predominant clinical signs of PRRS are acute reproductive losses in the sow herd and chronic respiratory disease in young pigs. Based on current knowledge, several strategies have been proposed to help control or eliminate PRRS from an infected herd. Even with the advent of a new vaccine the current control plans do not always work, or a herd that has become free of virus may become reinfected. Additional information is needed on how the PRRS virus is able to infect swine, persist in swine, and cause disease. This new information may be applied to update current plans for eliminating or controlling PRRS within a herd. In this paper we discuss our current research investigating the consequences of PRRS virus infection in sows and suggest how this information may be used by veterinarians in their day-to-day battle against PRRS. When a sow is infected with PRRS virus during late gestation it may only take 1-2 weeks for her fetuses to become infected with virus and begin to die. The virus may kill fetuses by attacking their blood vessels and/or the vessels of its associated placenta. We have demonstrated that sows develop a natural immunity to PRRS and this immunity may last for the life of the sow. Exposure to one strain of PRRS virus may lead to cross protection against a different strain of virus; however, the protection may not last very long.