Technical Abstract: The ABADRL has three 5-year project plans under two ARS National Research Programs. One project plan under the Animal Health National Program is entitled “Countermeasures to control and eradicate Rift Valley fever (RVF)”. Research objectives in this plan are 1) to determine the vector competence of North American mosquito species for both wild type and vaccine strains of RVFV; 2) to develop vaccine and diagnostic expression and delivery systems for RVFV; and 3) to develop operator safe, sensitive diagnostic tests for the early detection of RVFV, including assays to distinguish infected from vaccinated animals. A second project plan under the Animal Health national program is entitled “Virus-vector-host interactions of arboviral diseases of livestock” and focuses primarily on bluetongue virus (BTV) and vesicular stomatitis virus (VSV). Research objectives in this plan are 1) to identify biological determinants of disease susceptibility associated with arboviral infections; and 2) to determine the host-range specificity of exotic bluetongue viruses, namely the susceptibility of North American sheep and white-tailed deer to the European strain of BTV type 8. The project plan under the Veterinary, Medical, and Urban Entomology National Program is entitled “Vector competence and protection of US livestock and wildlife from arthropod-borne diseases” which includes research on important vector insect species of mosquitoes, midges, and sand flies and important arboviruses such as BTV, RVFV, and epizootic hemorrhagic disease virus (EHDV). Research objectives in this plan are 1) to determine the importance of North American biting insects as vectors of endemic and exotic pathogens; 2) to determine the biological factors that influence the risk of pathogen transmission by vector species; and 3) to develop strategies for protecting livestock and humans from biting insects.