Immunological Control of Rift Valley Fever Virus (Rvfv) in African Ruminants
Arthropod-Borne Animal Diseases Research
2013 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.
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. The primary objective is to develop the capacity and conduct clinical studies with RVFV. Future studies will include evaluation of attenuated and next generation of RVFV vaccines to determine their efficacy for disease control. Training KARI staff and purchase of necessary equipment has been accomplished. Twenty personnel who will be involved directly or indirectly with the project activities were vaccinated with the inactivated RVF vaccine (TSI-GSD-200). In preparation for animal studies, sera from sixty sheep targeted for use in the titration of the challenge virus was checked for probable presence of RVF virus by qPCR. They were all negative for RVFV presence. The Serum Neutralization Test (SNT) or ELISA to check for RVFV antibody is planned for the next quarter.