Project Number: 5410-32000-018-00
Project Type: Appropriated

Start Date: Dec 11, 2008
End Date: Apr 30, 2012

Objective:
Objective 1: Identify biological determinants of disease susceptibility associated with arboviral infections. Subobjective 1A. Assess the role of insect salivary proteins on the pathogenesis of bluetongue virus in relevant target vertebrate hosts. Subobjective 1B. Assess the role of insect salivary proteins on the pathogenesis of vesicular stomatitis virus in relevant target vertebrate hosts. Subobjective 1C. Identify and characterize the vertebrate host receptors for bluetongue virus. Subobjective 1D. Assess vesicular stomatitis virus-induced physiological variations and determine their affect on vector-host selection. Objective 2: Determine the host-range specificity of exotic bluetongue viruses. Subobjective 2A: Determine the susceptibility of U.S livestock to exotic bluetongue virus. Subobjective 2B: Determine the susceptibility of U.S wildlife to exotic bluetongue virus.

Approach:
Arthropod-borne diseases pose significant concerns to the U.S. livestock industry. This project will investigate several biological relationships among host, vector and virus that will lead to improved disease control and risk assessment of emerging and re-emerging, domestic and exotic arboviruses. Biological determinants of arthropod-borne viral diseases of animals can be associated with the insect vector, the arbovirus, or the animal. One potential insect determinant is insect saliva, which may affect arbovirus transmission and subsequent infection. Culicoides sonorensis saliva will be used to examine interactions between saliva, arboviruses, and the immune response of susceptible animals. This may help to identify ways to interrupt disease transmission. A second important arboviral-animal determinant is virus attachment, mediated by cellular receptor(s) and allowing subsequent infection. Candidate receptor molecules for bluetongue virus (BTV) will be identified from sub-cellular fractions. This will provide a better understanding of BTV pathogenesis and may lead to more targeted vaccine strategies. The final biological determinant to be addressed is the effect of virus infection on host selection by insect vectors. The effect of vesicular stomatitis virus (VSV) infection on insect feeding and host defensive behaviors that could affect virus acquisition and transmission will be examined. This may help in the design and implementation of more efficient and cost-effective bite transmission control strategies. Introduction of exotic arboviruses is an ongoing risk and reality. The susceptibility of North American sheep and white-tailed deer to BTV-8, which is causing devastating disease in Europe, will be determined to provide valuable information for risk assessment.