PREFACE

The discipline of wildlife diseases is a dynamic field of increasing importance to a conservation­conscious society. Beginning as a secondary interest among a group of wildlife managers in the early 1900s, it became a formal field of study with the formation of the Wildlife Dis­ease Association (WDA) in 1951; at that time the WDA primarily comprised wildlife profession­als trained in traditional wildlife management, as well as some veterinarians, but all sharing an interest in better understanding the role of diseases in wildlife populations.

In the intervening years, our increased understanding of wildlife diseases has led to clarifying significant conservation issues; we recognize that the relationships among vertebrate wildlife, infectious agents, ecologi­cal disturbances and loss, pollutants, climate change, invasive species, and other factors are very complex. Making sense of the multitude of specific relationships can be overwhelming. Most of these problems cannot be successfully addressed by any one professional, and require networking of specialists in diverse fields to obtain better understandings. Trained conser­vation professionals, as well as veterinarians with a wildlife background, are essential for successfully addressing these issues. For under­graduate and graduate students interested in wildlife diseases, we present a foundation for thinking about infective agents and their inter­actions with wildlife.

This book is intended as a first formal intro­duction to the field of wildlife diseases written for upper-division and graduate students who have a good foundational grounding in biology and zoology; these include students studying wildlife and natural resources, as well as the natural and biological sciences, and veterinary students who are extending their interests to dis­eases of wildlife. We do not expect that students necessarily have extensive foundations in micro­biology, parasitology, or other disease issues.

With the ideas of this text, we hope students will come to understand the basic life history strategies used by infective agents for being successful among vertebrate wildlife, as well as understanding the mechanisms by which wild­life can defend themselves from these agents. Hosts and infective agents each constantly evolve new tools and strategies to gain an advan­tage over the other. We envision host-infective agent relations as a dynamic “evolutionary dance” in which each vertebrate host and each infective agent has an array of tools and strat­egies for gaining an advantage over the other, and for countering the tools and strategies of the other. Current wildlife disease relationships are the result of a perpetual natural selection for successful tools and strategies among both wildlife hosts and the infective agents. Under­standing these relationships is key to more fully understanding the ecology and evolution of wildlife diseases and to laying the foundation to better understand the important contempo­rary and leading-edge work being conducted in the field.

We use a natural history approach to provide a general introduction to wildlife diseases, pull­ing together information that is distributed over a wide variety of texts and professional publica­tions into one concise source for the reader. We first give an overview and some basic definitions needed for understanding wildlife diseases. Because of its importance and applicability for all discussions of the infective agents, we next outline basic methods of defense employed by vertebrate hosts. This is followed by outlining the major life history strategies found among infective agents. We also cover some important noninfectious diseases of wildlife, and a few special problems and emerging diseases.

Our primary focus among wildlife is on mammals and birds, with limited coverage of amphibians and reptiles. Arthropods and other invertebrates are addressed as contributors to important disease processes among these wildlife hosts.

For taxonomic purposes, we generally fol­low traditional lines of parasite classification, but we also include recent changes reflect­ing new evolutionary perspectives. We do not attempt comprehensive coverage of each taxo­nomic group, but emphasize an understanding of the variation in life history strategies among those members within each group causing dis­eases among wildlife. We then present one or two examples of wildlife pathogens as illustra­tions of the main life history strategies in the group. For the wildlife pathogens presented, we provide a consistent organizational approach to allow readers to more easily compare key features among infective agents.

The text is not intended as a descriptive survey of the most common or even the most serious wildlife diseases, a strategy often used in parasitology or medical microbiology texts. It will not compete with the specialized infectious and parasitic disease texts that play an important role in summarizing the major diseases affecting vertebrate animals. But by providing a clear foundation for understand­ing how wildlife and infective agents interact, our text provides an important foundation for readers to use these more specialized texts as they continue developing as wildlife disease professionals.

We acknowledge, but do not develop, such contemporary and important wildlife disease topics as invasion biology and impacts on faunal structure, co-evolutionary relations, the roles of climate change and ecological disturbances as contributors to the emergence of new diseases, or ecosystem approaches to understanding the complex interactions of pathogens and the resulting patterns of disease. Rather, the text is intended to provide the foundation needed by students to thoughtfully and intelligently address these and other critical topics. Where possible, we also identify early sources of sig­nificant ideas in our discipline’s history; giving credit for the ideas allows us to appreciate the early innovative researchers, and better under­stand the evolution of thinking on these topics.

We hope you as readers enjoy learning and reflecting on this fascinating, dynamic field of study!