Recent research in our laboratories has identified 2 new bocaviruses in swine. We have isolated these 2 viruses, which are each antigenically different, from farms in Northern Ireland with clinical postweaning multisystemic wasting syndrome (PMWS) and preliminary partial molecular characterisation of these viruses has shown that they share genetic homology with bovine parvovirus-1 (BPV-1), canine minute virus (CMV) and human bocavirus (HBoV). To date, the disease-causing significance of these novel swine bocaviruses, as primary pathogens or perhaps as immunosuppresive triggers for other infectious agents, is undetermined. Investigation of the importance of these viruses in swine and humans as potential emerging pathogens is urgently required. It is possible that these newly identified swine bocaviruses could be pathogenic to swine and may also have a zoonotic potential. Whether swine bocaviruses have implications as a debilitating primary infection in pigs and/or humans or as a contributory infection, perhaps acting as an immunosuppressive infectious agent, merits urgent investigation. This genomic sequence data of the viruses generated to date will be expanded and used to produce tools for detection of swine bocaviruses in tissue samples and blood. Monoclonal and polyclonal antibodies will be produced to all 2 new swine bocaviruses to further study the biological characterisation, epidemiology and potential pathogenesis of swine bocaviruses in swine and other species. Experimental infections of swine will be carried out to determine sites of replication of these viruses and potential pathogenesis. Archived tissue samples from diseased and non-diseaed swine (including foetal material) in the UK will be examined and prospective field studies will be carried out. The possible 'contamination' of swine biologicals, including vaccines with swine bocavirus will also be investigated. On the basis of recent findings reported for other bocaviruses (including human bocavirus) we believe that our newly discovered swine bocaviruses may have the capacity to cause respiratory infections and/or reproductive problems and/or contribute to the severity of PMWS in swine. We also hypothesise that other existing porcine viral pathogens may have an increased severity due to the presence of these new viruses. Therefore, the hypothesis to be tested is that 'newly discovered swine bocaviruses will cause respiratory and other disease scenarios in pigs and that the virus isolates will exacerbate symptoms in pigs already suffering from other disorders. Additionally an experimental model of infection with swine bocavirus could prove useful in the study of human bocavirus infections. In this project hitherto-unavailable reagents, diagnostic tests and experimental models will be developed and applied to provide information relating to the characterisation, detection, epidemiology and pathogenicity of newly discovered bocaviruses of swine. Those newly discovered isolates will be fully characterised at nucleotide level and biologically using current techniques that have already been applied in our laboratory for the discovery of other novel viral pathogens.