Friday, June 28, 2019

Zoonotics as Parable

Choosing the road less taken can make all the difference. (Robert Frost)
About 60 percent of all human diseases and 75 percent of all emerging infectious diseases are zoonotic, according to the researchers. Most human infections with zoonoses come from livestock, including pigs, chickens, cattle, goats, sheep and camels.” (

I don’t often venture into the medical sciences areas, mainly because my ignorance on the finer points would trip me up pretty quickly. Recent reading about the decline and near-decimation of the ancient Aztec, Mayan, Cherokee and Incan civilizations (in, particularly, Ronald Wright’s Stolen Continents) piqued my interest in zoonotics, the branch of medicine that studies the transmission of infection from animal to human. Most of us remember the near panic surrounding Hanta virus, an infection endemic—although harmless—to Deer Mice but deadly to humans not possessing an evolved immunity. We could add Aids, Avian ‘Flu, etc., etc.

Zoonoses hitchhiked to America from Europe and Asia aboard explorers’ and traders’ sailing ships in the 15th, 16th, and 17th Centuries. American natives hadn’t developed immunity to these hitchhikers because they didn’t exist in the New World and so populations were decimated; whole cities like Aztec Tenochtitlan (present-day Mexico City) were felled primarily by Zoonoses, not by a superior civilization.

The transfer of Zoonotic infection, of course, is significantly enhanced by proximity; the domestication of species has ensured that humans and a variety of animal species share common territory. As hunter-gatherers, humans would have suffered illness, but the likelihood of zoonotic virus/bacterial transmission was lessened by the infrequency of contact.

We have known since Old Testament time that improperly cooked pork can pass trichinosis from hogs to people. Although the vomiting and diarrhea result from a worm and not a virus/bacteria, the relationship between eating hogs and the possibility of contracting illness therefrom is analogous to the Zoonotic dilemma: since the agricultural revolution, we have made ourselves more and more dependent on a narrow range of domesticated plants and animals and in so doing, have exposed ourselves to a whole catalogue of hazards.

Moving from nomadic, hunting/gathering to a sedentary, agricultural lifestyle has, of course, vastly improved the availability of food but has also resulted in burgeoning populations and the clumping of humanity into villages, towns and, finally, metropolises. Smallpox once introduced into a human population became epidemic very quickly where people lived in close quarters; in the fifties, schools and churches shut down during measles, mumps, scarlet fever outbreaks, for obvious reasons.

The bigger you build your ships, the harder it is to steer them onto a new course. The history of living species being unable to adjust to changing conditions in time to avoid annihilation is epic. It’s estimated by some that the current rate of extinction of species is 10,000 times the prehistoric average, possibly up to one extinction every 5 minutes.i In historical terms, species like prairie songbirds, for instance, have been unable to adjust their food and habitat needs in order to survive the environmental changes humans have precipitated. The introduction of zoonoses to the American continents left the Aztecs, the Incas, the Mayans, the Cherokee and most other indigenous inhabitants defenseless. The surviving remnant was obviously weakened, often pock-marked by smallpox.

Human ingenuity created the current, rapid explosion of change, and this on a planet used only to the exceedingly slow adaptation of species a la Darwin’s natural selection and survival of the fittest principles. Whether or not human ingenuity is up to finding remedies for complications caused by too-rapid change will be evident if and when our history is written. With a population of 7,000,000,000+ individuals, we have created a massive challenge: “progress” has resulted in an awfully big human-species ship; climate change, super-bugs, resource depletion all represent massive, looming icebergs.

The conquest of the Americas was achieved by zoonoses and pillaging by greedy “pirates,” erroneously portrayed in our histories as courageous explorers and discoverers of lands . . . lands already settled, ironically. Their actions can be excused in part on the basis of ignorance; Henry Hudson, Christopher Columbus didn’t even know the simple remedy for scurvy, much less the devastating power of the world of microbes.

Ignorance can no longer excuse our reluctance to do what we can to lessen the effects of coming challenges or to prepare for their consequences. A three minute read is enough to “set the scene” that will be our climate iceberg.ii Unlike the aboriginal peoples of the Americas, we have the means to prevent and prepare; all we lack is the will.

Where I live, mustering the will to get serious about the future is made difficult because here on the prairies, our leadership is of the kind that insists on using the only available water to irrigate a lucrative potato patch while the house is burning. Unfortunately, I don’t think any of Moe, Kenney or Palliser would appreciate the analogy. 


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