Project Number: 1940-32000-058-00
Project Type: Appropriated

Start Date: Oct 27, 2011
End Date: Oct 26, 2016

Objective:
1. Elucidate the virus-vector-host interactions responsible for virulence and transmission. 1.1. Determine the tissue tropism in natural hosts after insect transmission and the events mediating viral infection, early pathogenesis, and transmission 1.2. Characterize the mechanisms of insect-to-insect transmission while co-feeding in cattle and assess the role of cattle as amplifying hosts for VSV. 1.3. Test the potentiation of VSV infection by S. vittatum salivary factors. 1.4. Testing virulence and transmissibility of VSV strains making incursions into northern Mexico (and/or southwestern US). 2. Ascertain the viral ecology of disease and factors mediating the re-emergence of VSV in the US. Genetically characterize the viral strains circulating in endemic areas of Mexico and the epidemiological and ecological factors associated with the emergence and maintenance of specific viral genetic lineages in endemic versus non-endemic settings.

Approach:
1. To examine the virus-vector-host interactions responsible for virulence and transmission, studies will be conducted to determine tissue tropism in cattle after viral infection through insect bite, and the events mediating viral infection, early pathogenesis and transmission. The mechanisms of insect-to-insect transmission while co-feeding in cattle will be characterized and the role of cattle of amplifying hosts for VSV will be assessed. Tests will be conducted to determine the level of potentiation of VSV infection by black fly (Simulium Vittatum) salivary gland factors. Studies will be conducted on the virulence and transmissibility of VSV strains making incursions into northern Mexico. 2. Viral strains circulating in endemic areas of Mexico will be genetically characterized, and the epidemiological and ecological factors associated with emergence and maintenance of the specific viral genetic lineages in endemic settings will be analyzed in comparison to non-endemic virus strains.