Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: 9/19/2010
Publication Date: 10/18/2010
Citation: Lager, K.M., Vincent, A.L., Ciacci-Zanella, J.R., Zanella, E.L., Miller, L.C., Kehrli, Jr., M.E. 2010. Pathogenesis studies of the 2009 pandemic influenza virus and pseudorabies virus from wild pigs in swine. In: Proceedings of the Brazilian Society for Virology XXI Meeting, October 18-20, 2010, Gramado, Rio Grande do Sul, Brazil. p. 33-34. Interpretive Summary:
Technical Abstract: Over the last ten years in the United States the epidemiology and ecology of swine flu and pseudorabies has been dynamic. Swine flu is caused by influenza A virus and the disease was first recognized in pigs concurrent with the 1918 Spanish flu pandemic in humans. Pigs displayed clinical signs similar to people affected by the Spanish flu. Reverse genetics has been used to demonstrate that during the 1918 Spanish flu pandemic, pigs and people were infected with a similar virus, an H1N1 influenza virus. In contrast to the severity of disease reported in people, experimental infection of swine with the 1918 Spanish flu virus produced minimal respiratory disease while it induced fatal infections in mice and ferrets. Although the 2009 pandemic H1N1 virus was not as pathogenic in people as the historical reports from 1918, the 2009 virus induced fatal disease in mice and ferrets and induced moderate disease in pigs. Understanding how influenza viruses cause disease and why there are species differences is the subject of intense research by many around the world. Pseudorabies virus (PRV) infection can induce respiratory disease, reproductive failure, and affect the central nervous system. PRV vaccines have been used to eradicate the virus from swine herds and even from entire countries. One weakness in PRV control and eradication programs is the indigenous PRV infection of feral swine. Since the eradication of PRV from the U.S. commercial swine herd, there have been rare case reports of commercial swine becoming infected with feral swine PRV isolates. The difficulty in controlling the expansion of the feral swine population in North America presents a chronic threat to the PRV-free status of the US commercial swine herd. A better understanding of this source of infection may lead to improved PRV control programs. This report summarizes studies investigating the pathogenicity and transmissibility of influenza viruses and feral swine PRV isolates from the U.S. in swine.