2011 Annual Report 1a.Objectives (from AD-416) Conduct clinical studies with the next generation of RVFV vaccines to determine their efficacy for disease control in Kenya. 1b.Approach (from AD-416) Implement clinical challenge studies to evaluate the ability of available RVFV vaccines to stop viremia post challenge thus block viral transmission to the mosquito host. The initial portion of the project is to develop vaccination dose strategies by evaluating the host immune response to vaccination in relevant domestic African ruminant species. Project also requires the development of a challenge model in relevant domestic African ruminant species to evaluate the ability of RVFV vaccine(s) to prevent transmission to a relevant mosquito vector. Preferably, the challenge model will account for commonly occurring natural challenges by using mosquito transmission. The vaccine challenge model will require a sub agreement with the Onderstepoort Veterinary Institute due to lack of Animal Biosafety level 3 (ABSL-3) facilities in Kenya. 3.Progress Report The desired long-term outcome of this research is to protect people in Africa from RVFV by developing a vaccine to protect domestic ruminants, which are the presumed reservoirs and are amplifying hosts. Facilities in Africa are being modernized, a requirement for the vaccination work to begin. 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.