Killer Plagues: Will they wipe us out or will we co-evolve?

Since the days of the cave man, the earth has never been a Garden of Eden, but a valley of Decision where resilience is essential to survival...To grow in the midst of dangers is the fate of the human race—René Dubois, Mirage of Heath

The raging epidemic of acquired immunodeficiency syndrome has shocked the world. It is still not comprehended widely that it is a natural, almost predictable, phenomenon—Joshua Lederberg

For most of our history, viral and bacterial plagues have mystified us and caused untold human fatalities. “They have caused more death and terror than war or any other calamity,” claims Frank Ryan, M.D. and author of “Virus X: Tracking the New Killer Plagues”. We all know about the Black Death or Black Plague (commonly attributed to Bubonic Plague) caused by the bacterium, Yersinia pestis and carried by fleas on black rats. The Black Plague devastated Europe and Asia in the mid 1300s, killing an estimated 75 million people, around 1/3 to 2/3 of Europe’s population at the time.


Another devastating killer was the virus for smallpox, which likely crossed over from animals to humans about 10,000 years ago. The disease attacked Alexander the Great’s army in 4th Century B.C. and killed Roman emperor Marcus Aurelius. It destroyed entire cultures. As recently as the 1960s over two million people were killed by the disease every year. Thanks to a worldwide anti-smallpox vaccination program, by May 8, 1980, the World Health Assembly officially declared it eradicated.

The influenza virus, the cause of a worldwide pandemic in 1918, killed over 20 million people, more than the number killed during the First World War then disappeared without a trace. The widespread use of antibiotics after World War II has brought under control killer diseases like pneumonia, tuberculosis, cholera, malaria, syphilis, meningitis and many others.

However, bacteria and viruses can evolve as much in a day as we evolve in a thousand years, giving them an advantage in evolving new mechanisms to evade our defences. Michio Kaku, author of “Visions” said, “The careless and rampant overuse of antibiotics today has killed off all but the strongest and most resistant bacteria. Our own bodies have become a Darwinian battleground where only the nastiest mutant strains of bacteria survive and thrive.” Although man can build a better mousetrap, nature always seems to build a better mouse.

As the pace of industrialization speeds up, scientists expect more emergent and resistant diseases to appear. Legionnaire’s disease, toxic shock syndrome, and Lyme disease are examples of diseases that have spread through modernization in North America. “There are now organisms, still fortunately rare, [that are] resistant to every antibiotic known,” Fred Tenover of the Centers for Disease Control, cautions. Today’s newspapers and internet columns overflow with articles on current plagues like AIDs, Ebola, “mad cow disease”, “flesh-eating” viruses. Plagues caused by new or “emerging” viruses are particularly alarming since there is often no cure or preventative vaccine.

Viruses are “the greatest threat to the survival of our species,” claims the Centre for Disease Control and Prevention (CDC), which has devoted itself to controlling the outbreak of viruses in the hopes of preventing a “Doomsday Virus” such as an airborne AIDs or Ebola virus from threatening the very existence of human life. Doctor Ryan asks the proverbial question: “Is there...a provable connection between the emergence of new plagues and the effects of human behaviour, our “vulnerable mono-culture” expansion and the exploitation of the delicate ecology of the world?” Is this Nature’s clarion call for us to re-examine our environmental choices and actions? Or is it something else?...

In a post a while ago, called “Co-evolution: Cooperation & Aggressive Symbiosis” I brought up the concept of co-evolution, using as an example the simple virus: the ecological "home" of the virus is the genome of any potential host and scientists have remained baffled by the overwhelming evidence for ‘accommodation’. Virologist, Dr. Frank Ryan calls co-evolution of virus and host “a wonderful marriage in nature—a partnership in which the definition of predator and prey blurs, until it seems to metamorphose to something altogether different.” Co-evolution is now an established theme in the biology of virus-host relationships. Relationships span from the complex interaction between arboviruses and their vector mosquitoes to the one between the malaria-causing plasmodium and humans or the hantavirus and the deer mouse. Ryan added that “today...every monkey, baboon, chimpanzee and gorilla is carrying at least ten different species of symbiotic viruses.”

“Why,” asks Ryan, “is co-evolution [and its partner, symbiosis] such a common pattern in nature?” Ryan coined the term “genomic intelligence” to explain the form of intelligence exerted by viruses and the capacity of the genome to be both receptive and responsive to nature. It involves an incredible interaction between the genetic template and nature that governs even viruses. Symbiosis and natural selection need not be viewed as mutually contradictory. Russian biologists, Andrei Famintsyn and Konstantine Merezhkovskii invented the term “symbiogenesis” to explain the fantastic synthesis of new living organisms from symbiotic unions. Citing the evolution of mitochondria and the chloroplast within a primitive host cell to form the more complex eukaryotic cell (as originally theorized by Lynn Margulis), Ryan noted that “it would be hard to imagine how the step by step gradualism of natural selection could have resulted in this brazenly passionate intercourse of life!”

In his book, “Virus X” Dr. Frank Ryan coined the term “aggressive symbiont” to explain a common form of symbiosis where one or both symbiotic partners demonstrates an aggressive and potentially harmful effect on the other’s competitor or potential predator. Examples abound, but a few are worth mentioning here. In the South American forests, a species of acacia tree produces a waxy berry of protein at the ends of its leaves that provides nourishment for the growing infants of the ant colony residing in the tree. The ants, in turn not only keep the foliage clear of herbivores and preying insects through a stinging assault, but they make hunting forays into the wilderness of the tree, destroying the growing shoots of potential rivals to the acacia. Viruses commonly form “aggressive symbiotic” relationships with their hosts, one example of which is the herpes-B virus, Herpesvirus saimiri, and the squirrel monkey (the virus induces cancer in the competing marmoset monkey). Ryan suggests that the Ebola and hantavirus outbreaks follow a similar pattern of “aggressive symbiosis”.

The historian, William H. McNeill, suggested that a form of “aggressive symbiosis” played a key role in the history of human civilization. “At every level of organization—molecular, cellular, organismic, and social—one confronts equilibrium [symbiotic] patterns. Within such equilibria, any alteration from ‘outside’ tends to provoke compensatory changes [aggressive symbiosis] throughout the system to minimize overall upheaval.” One of a legacy of examples of aggressive symbiosis in history includes smallpox: presumably in the process of symbiotic adaptation through co-evolution with the Europeans, they introduced it to the Aztecs with devastating results. Other examples include measles, malaria, and yellow fever.

As I said in my previous post, this puts a whole new twist on the concept of encroachment and development, doesn't it?...

Recommended Reading:

Kaku, Michiu. 1997. Visions: How Science Will Revolutionize the 21st Century. Anchor Books, Doubleday. New York, N.Y. 403pp.

Ryan, Frank, M.D. 1997. Virus X: Tracking the New Killer Plagues. Little, Brown and Company, New York, N.Y. 430pp.

Nina Munteanu is an ecologist and internationally published author of novels, short stories and essays. She coaches writers and teaches writing at George Brown College and the University of Toronto. For more about Nina’s coaching & workshops visit www.ninamunteanu.me. Visit www.ninamunteanu.ca for more about her writing.