CategorySwine Health - General Disease
Date Full Report Received06/01/2009
Date Abstract Report Received06/01/2009
InvestigationInstitution: National Animal Disease Center, USDA-ARS
Primary Investigator: Kelly Lager
Funded ByNational Pork Board
The objectives of the project “Etiology of severe form of PMWS” were 1) Investigate the etiology of an apparent emerging disease complex known as “severe form of Post-weaning Multisystemic Wasting Syndrome (PMWS),” and 2) Evaluate the feasibility of applying DNA-microarray technology for use in veterinary diagnostics. For objective 1, tissue samples collected from field cases of the severe form of PMWS were tested for viruses. As would be expected, a variety of swine viruses were detected in the sick pigs; however, one virus, porcine circovirus type 2 (PCV2), was found in all sampled pigs. Genetic analysis revealed the pigs were infected with a European-like PCV2, this was the first time the European-like virus had been found in the United States. How this virus came to the United States, and to what extent it played a role in the severe form of PMWS was not clear. To investigate further, germ-free pigs were inoculated with the European-like PCV2 and North American-like PCV2 viruses, both of these virus types were found in the same farm in one case. Under the conditions of the germ-free pig experiments, the effect on pigs was similar for both viruses. From an experimental perspective, there was no clear indication as to the clinical significance of the European-like PCV2 appearing in the United States. Additional study is required to determine if the European-like PCV2 is clinically distinct from the North American PCV2, a distinction that might contribute to the emergence of the new virus in the United States. For objective 2, a new technology designed to detect all known virus families was used for diagnostic purposes for some of the field cases described above. In addition to viruses detected by traditional methods, a novel swine virus was detecetd. Efforts are underway to fully characterize this virus at a genetic level as well as to determine if the virus is a pathogen in swine, or just another interesting virus that has been detected in pigs.