2010 Annual Report 1a.Objectives (from AD-416) To develop a mouse and/or hamster model for the direct comparison of attenuated and subunit RVF vaccine candidates. 1b.Approach (from AD-416) A number of attenuated vaccine candidates are being considered to control RVF. Evaluation of these candidate using the target species sheep, goats and cattle is very expensive. Therefore, the generation of a hamster model for the direct comparison of attenuated vaccine candidates would be beneficial. Mice or hamsters will be vaccinated with available candidate attenuated vaccines (MP-12, Clone 13, and/or double deletion mutant) and challenged with a virulent RVF virus. Groups of ten (10) hamsters will be vaccinated with a candidate or sham vaccine, monitored for one (1) month then challenged with a virulent RVF virus. We will attempt to import a highly virulent South African RVF virus that is genetic distinct from the usual ZH-501 challenge strain for this challenge. In addition, the hamster host immune response will characterized both by production of neutralizing immunity and by production of 2-4 standard immunological markers. The challenge studies will be repeated three times to increase the sample size and potentially the number immunological markers evaluated. 3.Progress Report The objective of this cooperative research is to develop a mouse and/or hamster model for the direct comparison of attenuated and subunit RVF vaccine candidates. Hamster cytokine qRT-PCR assays have been obtained and are being adapted to local instrumentation. Two strains of RVF virus have been obtained and proven to be virulent in the hamster model. The vaccine challenge experimental design has been developed and timeline established. 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.