Progress 09/01/24 to 08/31/25

Outputs
Target Audience:Stakeholders are pig farmers, veterinarians, pork industry, the global CSF research community and CSF scientists. The project is relevant to the goals of proactive prevention and control of Classical Swine Fever (CSF) which is a highly contagious pig disease widespread globally include South American countries. This work will contribute toward the development of a safe and efficacious virus-vectored CSF E protein-based vaccine for the prevention and eradication of CSF in both endemic and non-endemic countries. The vaccine can be produced cost efficient and stored for longer periods without safety concerns. Changes/Problems: major problems or delays that may have a significant impact on the rate of expenditure; changes to the approved Data Management Plan; significant deviations from the research schedule or goals; unexpected outcomes; or changes in approved protocols for the use or care of animals, human subjects, and/or biohazards encountered during the reporting period. What opportunities for training and professional development has the project provided?Two graduate students, two post-doctors and several senior scientists were involved in the development of the virus-vectored vaccines and animal studies. Since the CSF is the transboundary disease in the US and hands-on experience in the BSL-3 biocontainment will be a tremendous benefit for future research and protection from the disease for the US pig industry. How have the results been disseminated to communities of interest?The PDs presented the project and progress at the USDA NIFA Ag Biossecurity PD meeting in 2025. What do you plan to do during the next reporting period to accomplish the goals?We will start vaccine studies with the VSV and ORFV vaccine constructs and a combination of the two vaccine candidates in susceptible domestic pigs. We will use the CSFV antisera produced so far to develop a DIVA assay. Initial assay optimization will be initiated. We plan to develop a multiplex Luminex DIVA assay

Impacts
What was accomplished under these goals? 1. We have constructed two virus-vectored vaccines, ORFV- CSF E and VSV-CSFV E. Additionally, attempts are ongoing to construct ORFV-CSF Erns. The ORFV IA82 was used as a parental virus to construct the recombinant ORFV expressing the target gene of the CSFV (CSFV Brecia strain was the reference). Full length rVSV Indiana plasmid and four recombinant VSVS accessory plasmids encoding VS-N, VSVS-P, VSV-L and VSV-G proteins were used to construct the VSV-CSF E recombinant virus. We have successfully rescued both ORFV-CSF E and VSV-CSF E recombinant virus as vaccine candidates. Selection of the ORFV-CFS E and Erns are ongoing. 2. A CSF challenge model was established using the CSFV strain Brecia for infection. Clinical signs, gross lesions, histopathology, viral gene detection and serology have been established. Tissues of interest, blood and serum samples were collected for further analysis such as immune response and DIVA diagnostics. 3. The CSF virus antigens E1, E2, Erns and NSP3 have been cloned into a mammalian expression plasmids and recombinant proteins are being produced for DIVA assay development. These proteins will be

Publications