The geographic ranges of both ticks and tick-borne pathogens have expanded over the past several decades in the United States. These changes are likely the result of several synergistic factors, including dramatic increases in the populations of white-tailed deer (Odocoileus virgnianus), a preferred host for several tick species; land use changes from agriculture to forest; and a shifting of human populations from urban centers to the wildland-urban interface. New tickborne zoonoses have appeared, including human monocytotropic ehrlichiosis (HME), caused by Ehrlichia chaffeensis; and human granulocytic anaplasmosis (HGA) caused by Anaplasma phagocytophilum. Maps of these and other emerging pathogens can play an important role in the assessment of regional public health. From a practical standpoint, knowing the spatial distribution of disease risk can help to allocate scarce resources for prevention and control strategies. When these maps are based on ecological relationships, the mapping process can enhance our knowledge of the environmental and anthropogenic factors that constrain geographic distributions of vectors, pathogens, and diseases. Ecological models can be used to identify unoccupied areas of suitable habitat where vectors and pathogens may eventually expand their ranges, or can be linked to projections of climate and land use changes to assess whether future landscapes will be more or less amenable to the spread of disease.

Researchers from the Warnell School of Forestry and Natural Resources (Mike Wimberly and Randy Davidson) and the Southeastern Coorperative Wildlife Disease Study (Michael Yabsley) are applying concepts and methods from landscape ecology to enhance our understanding of vector ecology and pathogen distributions across multiple spatial scales. This new knowledge will improve the accuracy of disease risk maps.