Start Date: Dec 23, 2006
End Date: Dec 22, 2011
First, we will establish an infection model in cattle that allows close examination of the first few hours post-exposure. Identification of key tissues(s) and cell types responsible for primary virus replication and virus-host interactions that lead to control of local infection or generalized disease can be accomplished utilizing molecular tools such as confocal and laser-capture micro-dissection microscopy, in situ RT-PCR hybridization, and microarray analysis of host and viral genes. Second, we will utilize transposon insertion mutagenesis of an infectious FMD clone, to create a series of mutant viruses to be tested in the model developed under objective 1 to identify virulence determinants of FMDV. Viable mutants will be tested for their ability to invade and colonize primary replication site(s), generalize, cause clinical disease, and persist. Third, we will utilize VSV inoculation by insect bite and treatment with insect salivary components, combined with skin sampling and molecular tools described in the first objective, to determine the effect of insect bite on VSV pathogenesis. Information derived from the detailed understanding of early events in FMDV and VSV infections will provide a basis for disease control strategies that target essential steps in viral infection.