Lyme disease: a quintessential connection between ecosystems and human Health

Abstract

The topic of emerging infectious diseases, including novel pathogens as well as those that have reemerged or spread into new geographic areas, is a subject of growing interest in the fields of disease ecology and public health. Many of these emerging diseases have strong ecological underpinnings because of their dependence upon arthropod vectors for transmission and zoonotic hosts as reservoirs. As a result, disease emergence is often affected by human-caused changes in climate and habitat that alter the ecologies of vector and host species, and the field of landscape ecology has the potential to make a significant contribution in the quest for new approaches to understanding and preventing these diseases. Lyme disease is a tick-borne disease that is caused by the spirochete Borrelia burgdorferi, vectored by the black-legged tick Ixodes scapularis, and dependent upon a variety of zoonotic reservoir hosts. It is arguably the most important vector-borne disease in North America and has emerged conspicuously over the past several decades. In the United States, cases have increased from less than 1,000 per year in the early 1980s to more than 30,000 confirmed and probable cases in 2010. In his book entitled Lyme Disease, the Ecology of a Complex System, Richard Ostfeld provides an ecologist’s perspective on the phenomenon of Lyme disease. This book delivers a unique scientific narrative that highlights several ongoing scientific controversies about Lyme disease ecology and is grounded in the author’s own extensive research on this topic. The book starts with a brief introduction to the history of Lyme disease and the public health controversies that surround this insidious ailment. The next several chapters are then devoted to exploring and deconstructing several prevailing hypotheses about the ecological determinants of Lyme disease risk. These include the role of the white-tailed deer as a keystone host necessary for maintaining high tick densities, the importance of the white-footed mouse as the primary reservoir host species involved in Borrelia burgdorferi transmission, and the influences of weather and microhabitats on tick populations. Although there is some evidence to support each of these hypotheses, Ostfeld highlights the many contradictory results in the scientific literature which suggest that a more sophisticated framework is necessary for understanding the complex ecology of Lyme disease. In the second half of the book, Ostfeld focuses on the presentation and synthesis of the results from his own research group emphasizing the importance of biodiversity and ecosystem function for understanding the ecology of complex zoonoses such as Lyme disease. Two key themes in this section of the book are the cascading effects of mast years through ecological food webs and how the biology and behavior of M. C. Wimberly (&) Geographic Information Science Center of Excellence, South Dakota State University, Brookings, SD 57007, USA e-mail: michael.wimberly@sdstate.edu