Written by David Quammen, "Spillover" is a highly engaging (at least to me) exploration of animal infections and the perils they pose for people. Diseases such as influenza, hendra virus or HIV live in animals such as water fowl, bats or chimpanzees and as long as they do, the bug can cross to humans and have the potential to ignite a new epidemic. In fact, some 60 percent of the infections that plague humankind originated in the bodies of other animals.
The emergence of zoonotic diseases is not a new phenomenon, but they do seem to be on the rise or at the very least hitting the news with an all too frequent occurrence. Throughout the book, Quammen explores the reasons behind this and in his last chapter touches on the impact of our exploding human population, the surge in the population of livestock and our ever increasing destruction of natural habitats. As Quammen is careful to emphasise, humans are a part of the natural world. This is the crux of the problem as we like to think of ourselves as living distinctly separate lives from the wilds around us when we are in fact very much in the thick of things.
Spillover is a detective story with a difference as it includes a large host of murderers, all of which are factual. The viruses, bacteria and other single-celled organisms which primarily infect animals find a way to make the jump or 'spill over' to humans. Each chapter follows the quest to track down a new villain detailing the perils of discovery along the way and the impact (good or bad) on the researchers trying to find the answer. But Quammen is quick to point out that pathogens can’t just rampage unconstrained. In order to survive they need to find the balance between their disease-causing activities inside their host with their need for that same host to carry them into their next victim through coughing, having sex or contaminating the drinking water. If the pathogen gets the balance between transmission and virulence wrong they will die out. As Quammen states, that’s why Ebola is limited in its pandemic potential....that was at least before 2014!
If you only read Spillover for the chapter on Ebola, it will be worth it for in that chapter is a very real situation of how things can change. Ebola in the course of a year, went from a pathogen that caused fewer than 3000 deaths since identified in 1976 to over 10,000 deaths in 2014.
If you're a germ enthusiast and are looking for a book based on facts that you hope after reading was fiction, then Spillover is definitely the book for you!