Review by Aniruddha Belsare

Understanding the complexity of multihost pathogen systems has been recognized as one of the major challenges of biomedical sciences for the 21st century. This challenge is undeniable—our experiences of responding to recent and ongoing disease outbreaks just in the first two decades of this century have clearly brought home the critical importance of understanding the intricacies of zoonotic and wildlife disease systems. The emerging discipline of disease ecology is particularly relevant in this context. Disease ecology provides insights into how diseases spread and evolve by examining the interactions between hosts, pathogens, and their environment. As a quintessential interdisciplinary field, disease ecology combines principles from ecology, biology, epidemiology, and environmental science to better understand host-pathogen-environment interactions. Such understanding is crucial for developing effective agricultural policies, public health strategies, and conservation practices. For instance, disease ecology can help in predicting infectious disease outbreaks, designing better control measures, and managing wildlife populations to prevent the spillover of zoonoses. As our world changes rapidly, the insights from disease ecology become even more valuable for tackling emerging and reemerging infectious diseases.

This book serves as an introduction to disease ecology, with a focus on zoonotic and wildlife diseases. The first chapter lays the foundation by introducing key concepts related to the emergence of zoonotic diseases, setting the stage for the rest of the text. The remainder of the book is divided in four sections, systematically exposing the reader to tools, techniques, and terminology necessary for understanding host-pathogen dynamics (Section 1: Describing Outbreaks; Chapters 2–5); exploring how pathogens persist in the environment or reservoir host species (Section 2: Pathogen Sources; Chapters 6–8); then discussing how and why diseases emerge (Section 3: Drivers of Infectious Disease Emergence; Chapters 9–11); and finally delving into how pathogens impact host populations (Section 4: Conservation, Ecology, and Control; Chapters 12–15).

The authors provide clear definitions of important key terms related to disease emergence in the first chapter. However, they also caution readers that definitions can be fluid, advising them not to get bogged down by them. Hopefully, keen readers will build on these discussions and pose insightful questions such as “When does a zoonotic spillover become an emerging infectious disease?” The case studies presented in this chapter vividly demonstrate the real-world relevance of this discipline and underscore the practical applications of disease ecology. I will play a curmudgeon and argue that this chapter would have been a perfect opportunity to introduce the concept of One Health, even though the authors do cover the topic in the last chapter (Chapter 15: COVID-19, One Health, and Pandemic Prevention). In the second chapter, the authors discuss pathogen transmission mechanisms, pathogen entry and exit mechanisms in exposed hosts, and progression of infection within a host. The third chapter focuses on understanding disease outbreaks using epidemic curves and diagnostic tests. The emphasis on test result interpretation and test validity is particularly helpful. The fourth chapter explores the topic of pathogen or disease surveillance, but is mostly limited to tick-borne disease surveillance. Discussions of broader issues affecting real-world wildlife disease surveillance are noticeably absent in this chapter. The case study of the wildlife biologist from Arizona contracting pneumonic plague from a mountain lion is intriguing and important to discuss, but it feels out of place in this chapter. Chapter 5 covers disease modeling and provides a comprehensive overview of compartmental models and their applications for understanding disease dynamics. The three chapters in Section 2 (6–8) delve into topics related to the persistence of pathogens in the environment or reservoir host species. Case studies presented in this section take the reader on a fantastic voyage around the planet, from the emerging outbreak of white-nose syndrome in bats in North America, to anthrax in the herbivore community in Namibia and in reindeer in northern Siberia (Russia), histoplasmosis outbreaks in Arkansas and Louisiana (USA), a campylobacteriosis outbreak in New Zealand, toxoplasmosis in California, armadillo leprosy in the Americas, rabies and canine distemper in dogs and wildlife in the Serengeti, Tanzania, Lyme disease in North America, and Ebola virus in Africa! In Section 3, Chapter 9 explores how globalization is driving disease emergence across the planet. The next two chapters in this section discuss the impact of climate change and land use change on emerging infectious diseases. In Section 4, the authors discuss conservation implications of wildlife disease outbreaks in Chapter 12, using case studies such as mange in Arctic fox, rabies in Ethiopian wolf, canine distemper in Iberian lynx, and chytrid fungus in amphibians. Chapter 13 explores the cascading effects of infectious diseases on host communities and the ecosystem. This chapter also addresses the topic of co-infection, but notably omits some well-known studies, such as those on helminth-bovine tuberculosis co-infection in wild African buffalo. Chapter 15 covers contemporary approaches to wildlife disease control using several relevant case studies. There is an interesting discussion of the unintended consequences of human interventions, using the case study of brucellosis in the Greater Yellowstone ecosystem. The Guinea worm disease example is also very relevant as it highlights the real-world challenges of disease control programs. The final chapter of this book examines the COVID-19 pandemic through the lens of a disease ecologist, effectively showcasing the application of concepts and principles discussed throughout the text.

The integration of ecological and epidemiological concepts or approaches in the study of infectious diseases can be overwhelming, especially for those new to the field of disease ecology. Additionally, staying current with the expanding body of literature, which is continually updated with new insights and findings, can be a daunting challenge for students. To help overcome these difficulties, the authors employ intriguing real-world case studies to enhance understanding and practical application of the concepts discussed in this book. It is ideal for anyone planning a career in wildlife disease research, especially those focusing on diseases with agricultural, public health, or conservation implications. The book introduces core concepts to early career professionals and students, helping them advance, while also benefiting readers looking to refine their approach as disease ecology researchers or practitioners. What truly sets this book apart from most textbooks is the tongue-in-cheek humor the authors have infused throughout.

© Wildlife Disease Association 2025