man exposure to infected ticks in the environment constitutes risk, which determines the distribution and prevalence of Lyme disease (Fish, 1995).
Application of landscape epidemiology to Lyme disease has had a significant impact on our understanding of this epidemic and on the implementation of prevention measures. Early field studies identified the importance of peridomestic risk in the suburban landscape in the north-eastern states (Falco and Fish, 1988a, 1988b), which enabled public health agencies to target high-risk populations for education on preventive measures. The CDC Advisory Committee on Immunization Practices issued guidelines for vaccination against Lyme disease based entirely on a national Lyme disease risk map generated from ecological data on the distribution and prevalence of infection in vector ticks throughout the United States (Fish and Howard, 1999).
The threat of emerging diseases from wildlife and vectors is a continuous, dynamic process, which most likely will accelerate due to human population growth and more extensive environmental change. Therefore, it is imperative that more emphasis be placed on environmental studies of infectious agents in order to balance our overreliance on diagnostics, therapeutics, and vaccines for humans, which at present dominate the biomedical research effort in emerging infectious diseases (Morens et al., 2004).
Terrestrial mineral resources include abundant metals, scarce metals, water, soil, building materials, and a wide range of chemicals, including carbon-based fuels and nuclear energy sources. The quarrying of construction materials, the mining of ore deposits and coal, and the drilling for and production of oil and natural gas take place in relatively restricted areas, especially compared with the widespread land surface modifications wrought by agricultural, forestry, urban, and industrial development and the resultant degradation of the air, land, and water environments (Gleick, 1998; Harrison and Pearce, 2000; IPCC, 2001a, 2001b; Wolman, 2002). Over the period of intense resource exploitation activity between 1930 and 1980, less than 1% of the total land area of the United States was directly impacted by coal mining, mineral mining, and petroleum production activities (Johnson and Paone, 1982). However, topographic alteration, groundwater and surface water contamination, and hydrocarbon pollution are far more serious than this small areal percentage might suggest because of the high toxicity of a proportion of the mining waste and petroleum products. The extraction, beneficiation, and usage of earth materials, including fossil fuels, result in deleterious side