2010 Annual Report 1a.Objectives (from AD-416) To characterize the susceptibility, pathogenesis, and virus-vector-host interactions in bluetongue virus (BTV) and vesicular stomatitis virus (VSV) animal infections. 1b.Approach (from AD-416) Animal infection studies will be conducted with vesicular stomatitis virus (VSV)and exotic bluetongue virus (BTV). The role of Culicoides sonorensis midge saliva in the ability of vesicular stomatitis virus to establish infection, replicate, and persist, will be examined using feral pigs. The physiological variations in VSV infected bats and guinea pigs and their affect on vector-host selection will be determined. The susceptibility of U.S. sheep and white-tailed deer to infection by exotic BTV serotype 8 will be determined. Bite rates, viral transmission, infection rates and pathogenesis will be measured by methods to include: clinical disease observations, virus isolation/plaque assay, polymerase chain reaction, ELISA, ethogram cataloging, videography, necropsy, histopathology, and immunohistochemistry. For all studies, scientists with complementary expertise from both parties will work together to obtain, analyze, and interpret the research data. 3.Progress Report Three significant efforts were expended on this project: 1) After extensive efforts, an APHIS permit to import bluetongue 8 virus from the Netherlands was obtained. 2) Challenge of two sheep with BT8 virus. Two young sheep were purchased, confirmed to be bluetongue seronegative, then infected with the BT8 virus obtained from Netherlands. Those sheep were monitored for clinical disease for 15 days, and samples were assayed for viremia. The sheep failed to develop significant clinical disease, although they did manifest a marked febrile response 7 to 10 days post-inoculation, and both developed a viremia similar to what had been previously reported from the Netherlands. 3) Challenge of white-tailed deer. Ten young deer were obtained from the National Wildlife Health Center and transported to CSU ABSL3 facilities for acclimitization (2-3 deer per room). Eight of these deer were inoculated with BT8 and two were not inoculated. Deer were observed for clinical signs at least once daily for the duration of the study. Selected tissues from those deer that displayed clinical signs of disease were sectioned and evaluated by a pathologist. 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, email and phone calls.