Reminder: > *Dissertation Defense Announcement > To: The George Mason University Community* > > *Maj. Christine A. Tedrow > PhD Biodefense Candidate > College of Science > * > *Date: Thursday November 5, 2009 > Time: 1:00 p.m. > Place: George Mason University, Prince William campus > Discovery Hall Auditorium > > Dissertation Chair: Dr. Charles L. Bailey, Ph.D., National Center for Biodefense and Infectious Diseases > > Title: "Using Remote Sensing, Ecological Niche Modeling, and Geographic Information Systems for * *Rift Valley Fever Risk Assessment in the United States" * > > > *A copy of the dissertation is on reserve in the Johnson Center > Library, Fairfax campus. The doctoral project will not be read at the > meeting, but should be read in advance. * > > *All members of the George Mason University community are invited to > attend.* > > > ABSTRACT > > The primary goal in this study was to explore remote sensing, > ecological niche modeling, and Geographic Information Systems (GIS) as > aids in predicting candidate Rift Valley fever (RVF) competent vector > abundance and distribution in Virginia, and as means of estimating > where risk of establishment in mosquitoes and risk of transmission to > human populations would be greatest in Virginia. A second goal in > this study was to determine whether the remotely-sensed Normalized > Difference Vegetation Index (NDVI) can be used as a proxy variable of > local conditions for the development of mosquitoes to predict mosquito > species distribution and abundance in Virginia. As part of this > study, a mosquito surveillance database was compiled to archive the > historical patterns of mosquito species abundance in Virginia. In > addition, linkages between mosquito density and local environmental > and climatic patterns were spatially and temporally examined > > The present study affirms the potential role of remote sensing imagery > for species distribution prediction, and it demonstrates that > ecological niche modeling is a valuable predictive tool to analyze the > distributions of populations. The MaxEnt ecological niche modeling > program was used to model predicted ranges for potential RVF competent > vectors in Virginia. The MaxEnt model was shown to be robust, and the > candidate RVF competent vector predicted distribution map is presented. > > The Normalized Difference Vegetation Index (NDVI) was found to be the > most useful environmental-climatic variable to predict mosquito > species distribution and abundance in Virginia. However, these > results indicate that a more robust prediction is obtained by > including other environmental-climatic factors correlated to mosquito > densities (e.g., temperature, precipitation, elevation) with NDVI. > > The present study demonstrates that remote sensing and GIS can be used > with ecological niche and risk modeling methods to estimate risk of > virus establishment in mosquitoes and transmission to humans. Maps > delineating the geographic areas in Virginia with highest risk for RVF > establishment in mosquito populations and RVF disease transmission to > human populations were generated in a GIS using human, domestic > animal, and white-tailed deer population estimates and the MaxEnt > potential RVF competent vector species distribution prediction. > > The candidate RVF competent vector predicted distribution and RVF risk > maps presented in this study can help vector control agencies and > public health officials focus Rift Valley fever surveillance efforts > in geographic areas with large co-located populations of potential RVF > competent vectors and human, domestic animal, and wildlife hosts. >