Spillover: Animal Infections and the Next Human Pandemic

It was the first week of June, 2009: the second week of the first term of my second year of teaching at university. At that stage of the term, most of my colleagues, and myself were still pretty relaxed, still slightly hungover from vacation, but looking forward (albeit cautiously) to the term ahead. It was late afternoon on a Wednesday, and a handful of us were in the faculty room, chatting while some of us prepared to go home or waited for our next class, when one of the university's Discipline Officers stepped into the faculty room, and told us that we had to leave immediately. A foreign exchange student had just been diagnosed with A(H1N1), and the university was evacuating the premises and closing for ten days.

My colleagues and I just exchanged looks, and we were pretty much thinking the same thing: “There go our schedules.” Not to say we couldn't rework our schedules to account for this unforeseen vacation, but it was irritating nevertheless that we had barely gotten the term started and already we were going to be forced to re-jigger them. We were somewhat-worried about the fact that the school was shutting down because of A(H1N1), but it wasn't that big a concern. Back in 2003 the university had gotten up in arms over SARS, but as it turned out SARS didn't turn into the massive pandemic it had become elsewhere, and we believed A(H1N1) would act the same way.

We were wrong.

Over the next few days we grew increasingly nervous as we watched the news reports. Several students from our university had been diagnosed with the virus and were currently receiving treatment. It was when the first fatalities were reported that we realized A(H1N1) was not going to be the little squeak SARS had been; it was looking like it would turn into an actual, full-blown pandemic.

By the end of the ten-day quarantine, we'd gone back to work in a far more somber mood than when we'd started the term. The students who'd caught the virus, including the exchange student who'd brought it in in the first place, had survived, though many others around the country hadn't. The event was a sobering reminder for some, and for others, a lesson: not every virus that got to the Philippines would hiccup once it reached our shores and leave us mostly alone.

For my part, though, it reawakened an interest in epidemiology, something I was already interested in as a part of science fiction and thrillers, but at the time I hadn't yet found a popular-science book that would explain the concept to me with minimal technical language. It was only this year, when I discovered David Quammen's Spillover: Animal Infections and the Next Human Pandemic, that I decided it was high time to figure out what was going on with all these animal-to-human disease crossovers - and what they meant for the future.

The first thing I noticed about Spillover was its length: I was reading the Kindle version and it took me a while of relatively regular reading (with a break for Republic of Thieves) to get through it. To be fair, I tend to go more slowly while reading non-fiction, especially popular science, but it can be hard to judge how long a book really is when one is reading it in digital format. It only really struck me that I was in for a long ride when I looked down at the percentage counter at the bottom of the screen, and it read 35 percent when I'd just hit Chapter 50.

I did not, however, find the length to be an issue at all. Length is only a problem if the writing is terrible, and Quammen is not a bad writer at all. There were some moments when the writing dragged a little, but these were few and far between, and were connected with moments when Quammen was reiterating things that had already been stated earlier. For the most part, Quammen is an easy read, albeit more serious about his treatment of the subject matter than, say, Mary Roach, though he does try to play for some humor now and again to lighten the mood. Of course, the generally serious tone is likely because of the subject matter Quammen is writing about, which is very serious indeed.

According to Quammen, Spillover is an attempt to answer the most pressing questions about zoonotic diseases (meaning, diseases that originate in animals and then spread to humans). What are they, precisely? Where do they come from? How do they operate? And, more importantly, why are they becoming more and more prevalent? In an attempt to answer those questions, Quammen does in-depth investigations of some of the most notorious zoonotic diseases in recent years, a list that includes SARS, Ebola, malaria, and concludes with the most successful of the lot, AIDS.

Going back and forth between various points in both space and time, Quammen chases down answers in a manner that I find rather admirable, especially considering just where he goes and what he does: pursuing these diseases to their sources, and always doing so with the possibility that he might catch them, too. But aside from finding out the answers, he also tells the stories of the many dedicated scientists - especially the field scientists - who spend years doing research, trying to track down the answers to the same questions Quammen asks. Over and over again, Quammen makes clear that the work these scientists do, whether out in the field or in the lab, isn't very glamorous, but it is the kind of work that could, possibly, prevent the next massive pandemic - and save thousands upon thousands of lives in the process.

At the end of Spillover, Quammen answers the questions posed at the beginning in a manner that is both troubling, and at the same time, empowering. The answer is this: zoonotic diseases are not as new as many of us think, but the reason they're happening more frequently is because of the way our species has begun to alter the ecology of everything around us, including our own. “Shake a tree, and things fall out” is the statement Quammen uses to describe how humanity's spread into previously uncharted territory (like the formerly impenetrable, and therefore isolated, jungles and forests of Asia, Africa, and South America) puts us into contact with all sorts of unusual bugs, and how the trappings of civilization, like close living and agriculture, make it even easier for bacteria and viruses to make the evolutionary jump from their animal reservoirs to us - with potentially devastating results. Quammen puts it thusly:

“Human-caused ecological pressures and disruptions are bringing animal pathogens ever more into contact with human populations, while human technology and behavior are spreading those pathogens ever more widely and quickly.”

So if it's zoonotic disease is as inevitable as it seems, can the experts at least tell the rest of us what's going to hit us next, and where it's going to come from? Unfortunately, no: the experts admit that right now, there's no real way to tell where the next pandemic will come from, and as for what it is, they're relatively sure it's going to be an influenza, but really, they're kind of leery about even that. Here's what Quammen has to say on the matter of prediction:

“Prediction, in general, so far as all these diseases are concerned, is a tenuous proposition, more likely to yield false confidence than actionable intelligence.”

The one thing the experts do agree on, though, is that whatever it's going to be, it's going to be zoonotic in nature.

So where does that leave us? Read in one way, this could create a sense of paranoia, which is why I don't recommend this book at all for hypochondriacs. I will admit, this book did scare me some while I was reading it, because of how easy it is for one seemingly-harmless bacterium or virus to cross the evolutionary bridge and turn into something like the Spanish Flu, which killed thousands during the early 1900s.

And yet, I think the book is empowering, because it provides a means of understanding how these zoonotic diseases work, and therefore, how their spread can be at the very least mitigated. Here's what Greg Dwyer, one of the experts Quammen interviewed and who specializes in the more mathematical side of epidemiology, has to say on the impact that humanity's choices make, down at the level of the single individual:

”???individual effort, individual discernment, individual choice can have huge effects in averting the catastrophes that might otherwise sweep through a herd.”

Later on, Dwyer adds what that kind of individual choice can do, at the level of the entire species, responding to Quammen's question about how much does it matter that humans are capable of actually making conscious decisions regarding their actions:

“How much does it matter that humans are smart? ??? I guess I'm actually going to say that it matters a whole lot. Now that I stop to think about it carefully. I think it will matter a great deal.”

What that means is this: it's true that zoonotic diseases are all but inevitable. Humanity has reached such a density in terms of population, and such an advancement in terms of technology, that the emergence of a pandemic is almost just a matter of time. But what's important is that we do have the smarts to actually mitigate it before it cuts an enormous swath through the human population. It all boils down to making smart decisions, both as individuals and as groups of people - and making smart decisions only happens through careful investigation, planning, and education.

Overall, Spillover succeeds in the goals Quammen sets out for it at the beginning: it does a fine job of answering the questions Quammen lays out initially, and Quammen does his level best by seeking out the experts - wherever (or in some cases, whenever) they may be. The book is long, but that's only because Quammen really wants to be thorough in answering the questions he asks in the beginning, and he has succeeded in that, as well. His prose is pretty easy to read, and he does attempt some humor from time to time that may make the reader chuckle, but there are some moments when the whole thing tends to drag a bit; fortunately, those moments don't last very long. There are some parts that may cause readers with weaker stomachs to want to put the book down for good, and it's definitely the last book I would put in the hands of a hypochondriac, but this is still an interesting book to read - and an important one. If it is as Quammen and the experts say, then making smart decisions is all that stands between humanity and the next great pandemic - and Spillover can definitely help in informing and making those smart decisions for and in the future.