COUNTERMEASURES TO CONTROL AND ERADICATE RIFT VALLEY FEVER (RFV)
Location: Arthropod-Borne Animal Diseases Research
Title: Characterization of Neutralization Determinants on Epizootic Hemorrhagic Disease Virus
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: February 16, 2009
Publication Date: February 16, 2009
Citation: Mecham, J.O., Miller, M.M., Bennett, K.E., Reeves, W.K., Drolet, B.S., Wilson, W.C. 2009. Characterization of neutralization determinants on epizootic hemorrhagic disease virus. Meeting Abstract.
The control of Rift Valley Fever (RVF) outbreaks requires sensitive and specific diagnostics, effective vector monitoring and management, and vaccination of humans and animals. The Arthropod-Borne Animal Diseases Research Laboratory has a multidisciplinary scientific team comprised of microbiologists, entomologists, molecular biologists and veterinarians, who are addressing these three aspects of RFV control. The objectives of the research are: 1) Determine which North American species of mosquitoes could serve as competent vectors for both wild type RFV virus (RVFV) and attenuated RVFV vaccine candidates; 2) Develop expression and delivery systems to advance the discovery of diagnostics and vaccines; 3) Develop direct and indirect diagnostic tests for the early detection of RVFV, including the differentiation of infected from vaccinated animals. To accomplish these research objectives, the ABADRL has established a number of national and international collaborations. Vector competence studies with North American mosquito species have shown that both infection and dissemination of virus in the insect are required for effective transmission of RVFV to a susceptible vertebrate host. These studies also suggest vector competence is variable between populations of mosquitoes. In an initial study, a potential North American vector (Aedes aegypti) for RVFV failed to transmit an attenuated vaccine strain of this virus (MP12) from vaccinated sheep to hamsters. A second potential vector (culex quinquefasciatus) was not infected after feeding on blood from vaccinated sheep. On the diagnostic front, RVFV gene expression plasmids have been received from various collaborators and proteins expressed, purified, and incorporated into a binding enzyme-linked immunosorbent assay (b-ELISA). This assay detected specific anti-nucleocapsid and anti-glycoprotein antibody in the serum of sheep that had been experimentally infected with wild type RVFV. The expressed proteins, as well as MP12, are being used to produce antibody reagents for immunohistochemistry, and to develop additional diagnostic assays- such as a competitive ELISA. The laboratory is also developing multiplex real-time RT-PCR assays targeting all three RNA genome segments of RVFV. In cooperation with international collaborators, both the nucleic acid and antibody-based assays will be evaluated and validated with field specimens.