2011 Annual Report 1a.Objectives (from AD-416) The objective of this project is to evaluate RVF Clone 13 vaccine viability as a possible U.S. veterinary vaccine and to assess the safety of the vaccine, and thus facilitate USDA, Center for Veterinary Biologics (CVB) to consider licensure in the U.S. 1b.Approach (from AD-416) ABADRU will perform and coordinate exploratory research centered on: i) insect vector susceptibility, competency and transmissibility of Clone 13 vaccine strain, ii) reversion to virulence potential of Clone 13 vaccine strain, iii) ability of Clone 13 vaccine strain to prevent virulent RVF virus replication in young animals, and iv) onset of immunity studies. 3.Progress Report The Department of Homeland Security (DHS) is supporting an extension of ABADRU’s RVF research efforts to conduct evaluation of the efficacy and safety of potential commercial veterinary vaccines and complementary diagnostics that are currently unavailable in the U.S. This has resulted in additional studies through cooperative agreements with the U.S. Army Medical Research Institute for Infectious Diseases (USAMRIID), Colorado State University (CSU), and the Canadian Food Inspection Agency (CFIA). A number of U.S. species were shown to be competent for RVFV including Culex tarsalis. In addition, two populations of Aedes vexans were examined and it was determined that one population was competent and the other not. In order to determine the most favorable conditions for reassortment to occur, five USAMRIID laboratory strains of RVFV were sequenced. The purpose was to find two distinct strains to establish these factors. Sheep MP-12 vaccine trials have been conducted that provided no evidence that mosquitoes could be efficiently infected by MP-12 vaccinates. CFIA performed young sheep RVFV challenge studies and a vaccine challenge study that demonstrated this model could be used to evaluate vaccine candidates. CSU conducted the small animal and immunological characterization studies and the data is currently being compiled. The multiplex real-time PCR has been modified so that all three gene segments have optimal sensitivity. This assay has undergone laboratory validation and preliminary field validation. ELISAs have been developed, laboratory validated but the initial field evaluation failed due to delays associated with the shipment of the biological reagents. This research supports NP103 Action Plan Components 1. Biodefense Research, and 3. Prevent and Control Zoonotic Diseases. ADODR is directly involved in performance of the research and also monitors activities to evaluate research progress through site visits, meeting at conferences and through email and phone calls.