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An environmental toxicologist advocates embracing microbes as partners in human and agricultural health

Natural Defense: Enlisting Bugs and Germs to Protect Our Food and Health

Emily Monosson
Island Press
196 pp.
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For a generation raised on the vision of a synthetically safeguarded future—“Better Things for Better Living… Through Chemistry”—the inheritance of a volatile, ecologically distorted present has been a promise unfulfilled. The 20th century’s aggressive approach to disease control has delivered a collection of unwelcome surprises, from agrochemical toxicity to antimicrobial resistance. Disrupting the tenuous web of ecosystem interdependencies that govern health, Emily Monosson concludes in Natural Defense, is a zero-sum game. Artificially induced gains, elusive and transient, only hold the mirage of sustainability.

The question that Monosson sets out to answer is how to harness these powerful ecosystem dynamics for personal and planetary health. In an era of quick wins, how can we adopt the long vision to secure our health and the food systems that sustain us?

Employing a paired-chapter structure that underscores the connectivity between human and agricultural health, Natural Defense guides us through a lively, provocative consideration of more ecologically balanced approaches to a disease-free future. Some of the approaches profiled will bear fruit; others, Monosson cautions, will wither. Collectively, though, they represent a new paradigm that abandons attempts to dominate our environment and learns to leverage the interplay of natural systems.

Woven throughout the book are the intertwined themes of balance and precision. For much of the past century, we’ve managed to co-opt some of nature’s bioengineering—penicillin, for example, or Wolbachia-infected mosquitos that stymy viral replication—while not fully understanding the complex evolutionary context. Increasingly, though, our refined understanding of the delicate microbial balance upon which human, animal, and soil health depends is unlocking new pathways to disease control.


Synthetic pheromones have enabled some apple orchards to cut back on insecticides by as much as 75 percent.

Berry growers in California, for example, have long relied on methyl bromide soil sterilization to control fungal wilt. Year after year, though, the wilt has returned, promoting chemical dependence on a toxic gas. Monosson argues that total microbial annihilation is unsustainable, demonstrating instead how intact soil microbiomes self-regulate—recruiting beneficial microbes, pushing out disruptive pathogens, and achieving something of a steady state. The prospect that balanced, chemical-free, disease-suppressive conditions are within reach could be game-changing for disease control in an age of big agribusiness.

To be sure, many of these approaches could only have been forged in the crucible of our present moment. The current bioinformatics revolution, for example, is layered upon advances in computational power, next-generation sequencing, and the Internet-assisted maturation of data-sharing platforms such as GenBank.

Consider genome-based vaccine development—custom-designed antigens, coded not in ones and zeros but in nucleic acid base pairs—aimed at eliciting a desired immune response. Built on bioinformatics, the scope of use and potential effect are staggering.

Imagine a future where the lag from pathogen detection to vaccine deployment is weeks to months, rather than months to years. Pandemics move closer to becoming obsolete, and we stay one step ahead of ever-evolving infectious disease agents. Already this approach has produced a vectored Ebola virus vaccine that offered complete protection in a phase 3 field study and a DNA-based Zika virus vaccine candidate presently in phase 2 clinical trials.

For nearly a century, we have adopted standard infectious-disease treatment protocols that are the biological equivalent of carpet bombing the microbiome. This broad-spectrum approach is failing us, accelerating the development of antimicrobial resistance and emptying the medicine cabinet of viable control options.

But the annals of microbial warfare may offer a road map as we push across new frontiers in personalized medicine. Monosson dedicates a chapter to bacteriophage therapy and the curative potential of these targeted, precision-guided viral therapeutics in an increasingly postantibiotic world. Our policy and regulatory environment, however, has not kept pace with the technologies and knowledge base enabling this advance or with many of the other approaches profiled, limiting the scalability of innovations designed to address our most intractable disease-control challenges.

In Natural Defense, Monosson presents a vision for a future in which we embrace our role in—and learn to harness the transformative potential of—the planet’s web of biological relationships. In that humility, we may finally find the North Star on our journey toward a sustainable, healthy future.

About the author

The reviewer is at the U.S. Agency for International Development, Bangkok 10110, Thailand.

NOTE: The views and opinions expressed in this article are those of the author and do not necessarily reflect the official policy or position of any agency of the U.S. government.