1 Ian Hennessee is a PhD candidate with the Gangarosa Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA. Julie A. Clennon and Uriel Kitron are with the Department of Environmental Sciences, Emory University. Lance A. Waller is with the Department of Biostatistics and Bioinformatics, Emory University. J. Michael Bryan is with the Georgia Department of Public Health, Atlanta.