David Quammen is prescient. He appears to have predicted the 2014 Ebola outbreak and country jumping years before it happened. Alright, maybe he isn’t a diviner; maybe he merely pays attention to the scientists around him. After all, there’s a reason he is has been given an Academy Award in Literature and is a three-time winner of the National Magazine Award. Spillover: Animal Infections and the Next Human Pandemic explores the science behind human pandemics, and is a culmination of decades-long interest in animals, biology and travel. It is also an intelligent, thoughtful and occasionally, humorous book about the intersection between humans, disease, public health and the animal kingdom.
“Made no mistake; they are connected, these disease outbreaks coming one after another. And they are not simply happening to us; they represent the unintended results of things we are doing. They reflect the convergence of two forms of crisis on our planet. The first crisis is ecological, the second is medical.”
The writing is excellent and well-researched, with a list of citations for each chapter. While clearly well versed in biological concepts and the professional scientific field, Quammen writes with an eye to description, creating a liveliness in his stories. When I looked up his biography, it was with no real surprise that I learned he studied William Faulkner on a Rhodes scholarship–like Fauklner, he clearly has a deep love and respect for the natural world. The writing conveys complicated biological concepts in a way that captures the essence without oversimplifying, leaving both the novice and the more knowledgeable reader satisfied. If I have one complaint, it is that the humor present in his short stories isn’t as present; a fitting approach for the somberness of the subject, but I miss it nonetheless. Most of the humor here acknowledges journalistic license but a fair amount relates to the research process:
“If you read the recent scientific literature of disease ecology, which is highly mathematical, and which I do not recommend unless you are deeply interested or troubled with insomnia, you find the basic reproduction rate everywhere.”
What takes this book a step beyond the ordinary is that Quammen goes to where the science happens. Interviewing scientists in person, their anecdotes give the research the human touch, and are both instructive and amazing. I found myself deeply wishing my career had taken a different track–but I’m not courageous enough to be a field scientist. The scientists who are looking for the Ebola reservoir are particularly adventuresome: when they collect samples, they do their exploring in full haz-mat gear, including a personal respirator, which leads to interesting challenges. As Quammen summarizes:
“Wait a minute, lemme get this straight: You’re in a cave in Uganda, surrounded by Marburg [virus] and rabies and black forest cobras, wading through a slurry of dead bats, getting hit in the face by live ones…the walls are alive with thirsty ticks, and you can hardly breathe, and you can hardly see, and… you’ve got time to be claustrophobic?’
‘Uganda is not famous for its mine rescue teams,’ [Amman] said.”
Dude. Skydiving and cliff-jumping are for wimps. Trying being a field scientist studying disease.
Just fantastic stuff. If you were ever in doubt about why to get an influenza shot, the information is right here. And why you should be very, very careful about what you eat, particularly game and bushmeat.
For my own challenged memory, as well as any who want the low-down without the 500-plus pages, I’ll summarize the general outline of the book, and detour through a few of his particularly insightful notes. Seriously, there’s gold in this book.
The premise is straightforward, and outlined after a case example as introduction. Human activity is causing disintegration of the natural environment. We end up exposed (or our domesticated animals) to an unknown microscopic world. Our population is so numerous and so mobile that any disease that makes the leap to a new host has a amazingly large host population to work with. RNA’s propensity for mutation means even a very small number of viruses have a chance for success–in genetic terms.
The book starts with a chapter called “Pale Horse” exploring the Hendra virus, which popped up in 1994 in Brisbane, Australia at a stable for racehorses and made the jump to humans. It’s a small-scale outbreak, but gives the reader a personal angle on the story, and a more limited way to explore the facets of zoonosis, an infection that can be transmitted from animals to humans.
“It’s a mildly technical term, zoonosis, unfamiliar to most people, but it helps clarify the biological complexities behind the ominous headlines about swine flu, bird flu, SARS, emerging diseases in general, and the threat of a global pandemic. It helps us comprehend why medical science and public health campaigns have been able to conquer some horrific disease, such as smallpox and polio, but unable to conquer other horrific diseases, such as dengue and yellow fever. It says something essential about the origins of AIDS. It’s a word of the future, destined for heavy use in the twenty-first century.”
He follows a new outbreak in “Thirteen Gorillas,” a chapter on an outbreak that occurs in the tiny village of Mayibout after eighteen people died after eating a chimpanzee. It’s an important chapter that lays the groundwork of the history of Ebola. Interestingly, it also seems to have decimated our gorilla cousins at times–perhaps a physiological reason for the historical prohibition some tribes had on eating larger primates. A short chapter “Everything Comes from Somewhere” gives a short history of malaria research and mathematics. Although malaria was always considered a ‘vector-borne’ disease, he follows a story to Borneo of an intermediate host for a form of malaria that was thought to be relatively benign–the macaque monkeys and how mosquitoes seemed to be transferring disease from monkeys to people. “Dinner at the Rat Farm” examines the outbreak and discovery of SARS, its connection to the practice of dining on wild game, discovery of its amplifier host, the civet, and the reservoir, the bat. “The Deer, the Parrot, and the Kid Next Door” looks at bacteria zoonotic diseases, including psittacosis, Q fever and one prevalent in current medical consciousness, Lyme disease.
“Going Viral” reviews the relatively recent discovery of viruses, and how the biology of viruses differs from bacteria. “Viruses, from the beginning of virology, have been defined in the negative (not captured by a filter, not cultivable in chemical nutrients, not quite alive), and the most fundamental negative axiom is that a virion is not a cell.” It then goes into the discovery of herpes B, arising out of polio studies, and studies looking at animal reservoirs. He then generalizes to how these studies support the search for the “Next Big One,” and what it takes to be a threat. It’s likely one of the more complicated chapters for the reader without prior knowledge, but I found it quite satisfying, a review and expansion of some basic concepts. “Celestial Hosts” (!!), which goes into travel research for animal reservoirs and amplifiers, first to Bangladesh and then to Malaysia. There’s a fascinating section on bats in Africa and some serendipitous science.
“The Chimp and the River” was one of the hardest for me to read, as scores and scores of chimpanzees in research and zoos ended up being killed as HIV was discovered and a variant appeared to have chimps as a reservoir. If there’s anything worse than animals used in research, it’s wasting their lives. It also talks about the political dynamics that led from HIV in the Congo to it showing in the Haitian population post-Congolese independence. “It Depends” looks at influenza, giving a little insight into the incredibly simple genetics of the virus, which means mutation is particularly easy for influenza and why health officials are so insistent on vaccination.
—Viruses have extremely small amounts of genetic material, which leads them to have limited ability to repair errors during replication. This facilitates their extremely high mutation rate, unlike DNA-based organisms.
—Bats end up being a reservoir for a number of pathogens, and no one is exactly sure why. Part of the explanation likely has to do with their prevalence–wide-ranging with numerous species, apparently 1 in 4 mammal species is a bat. Part likely has to do with their large gatherings–they more consistently reach a critical community size needed for virus propagation (and not dead-end mutation), with regular newborns to keep viruses in new hosts. Another aspect is their socialibility–many bats are collective roosters. Flying is certainly part, meaning they are exposed to and expose a wide range of space. The other part might have to do with immunology, and possibly a reduced immune function during hiberantion.. Genetically, they “evolved to roughly their present form about 50 million years ago” which gives a long time for mutual adaptation to occur.