Land Use and Urbanization Patterns in an Established Enzootic Raccoon Rabies Area

We analyzed how land-use patterns and changes in urbanization influence positive raccoon rabies cases in an established enzootic area. County resolution was used and the study area included all 159 counties in Georgia. We obtained data on raccoons submitted from 2006 through 2010 for testing at the state public health labs due to exposure incidents with people or domesticated animals. The land-use patterns were extracted from the US Geological Survey’s National Land Cover Database from both 2001 and 2006. Odds ratios were calculated on 16 land-use variables that included natural topography, agricultural development, and urbanization. An additional variable, Submissions/Population density, was used to normalize counties and to account for population bias associated with rabies surveillance. The use of this demographic variable was substantiated by GIS clustering analysis. The outcome variable was heavily right skewed and over dispersed and therefore a negative binomial regression was used in this count statistics technique. The final analysis showed that low intensity residential development is associated with raccoon rabies cases while evergreen forest offers protection. This study supports the hypothesis that the raccoon rabies enzootic is maintained in those edge ecosystems of urbanization. It is advocated here that the public health animal rabies database to include GPS coordinates when reporting wildlife rabies submissions for testing to improve the resolution when studying the disease ecology of enzootic rabies