The main focus of "Spillover: Animal Infections and the Next Human Pandemic" is on zoonotic diseases, which are infections that jump from animals to humans. The book explores the origins of these diseases and the factors that contribute to their spread, emphasizing the importance of understanding these interactions to prevent future pandemics.

According to "Spillover: Animal Infections and the Next Human Pandemic," human activities such as deforestation and urbanization disrupt natural habitats, bringing humans into closer contact with wildlife. This increased interaction facilitates the transmission of diseases from animals to humans, highlighting the need for sustainable practices to protect both human and animal health.

David Quammen proposes that global cooperation and preparedness are essential for preventing future pandemics. He emphasizes the roles of scientists, governments, and international organizations in identifying and responding to outbreaks. By monitoring animal health and implementing sustainable practices, we can better prepare for and mitigate the impact of infectious diseases.