Submitted to: American Association of Swine Veterinarians Annual Meeting
Publication Type: Proceedings
Publication Acceptance Date: 2/15/2007
Publication Date: 3/3/2007
Citation: Lager, K.M., Gauger, P.C., Vincent, A.L., Cheung, A.K. 2007. PCVAD diagnosis and emerging diseases: building a systematic approach. In: Proceedings of the American Association of Swine Veterinarians Annual Meeting, March 3-6, 2007, Orlando, Florida. p. 525-528.
Technical Abstract: In the fall of 1994, case reports in Eastern Canada described a syndrome of an acute onset of high mortality in finishing age pigs. Within a year this syndrome was reported throughout swine dense regions in Canada and the United States. Diagnostic investigations into these cases detected many known pathogens; however, these pathogens were not typically associated with an acute onset of high mortality in older pigs and the cause of this syndrome was unknown. Tissue samples from affected swine were received from herds from 4 different states. Although several known pathogens were detected in one or more pigs, only porcine circovirus type 2 (PCV2) was consistently identified in all affected pigs. Genetic analysis of these PCV2 isolates revealed an apparent new genotype for North America. This genotype, known as PCV2 group 1, has been reported previously in Europe. Historically, only the PCV group 2 genotype has been recognized in North America. Over the last few years there have been reports from Europe about serious epidemics of swine disease that were attributed to the PCV2 genotype 1. It is possible the genotype 1 virus was recently introduced into North America and is responsible for these epidemics of high mortality in finishing swine prompting the syndrome to be called a "severe form" of porcine circovirus associated disease (PCVAD). However, it is possible the syndrome is attributed to another agent, or to the introduction of a new cofactor that may trigger PCV2 (genotype 1 and genotype 2) to induce the severe form of PCVAD. Preliminary animal testing suggests the PCV2 genotype 1 virus recovered from a U.S. case is very pathogenic; additional studies are planned to corroborate these findings.