Plagues and Peoples

Nobody comprehends the universe, because it is almost entirely out of sight.  We also can’t see the universe of microorganisms here on Earth, or fully comprehend their powerful influence.  Historian William McNeill learned that disease has played a major role in the human journey, and he wrote a fascinating introduction to our intimate companions, the parasites, in Plagues and Peoples.

All critters eat.  Hosts provide food, and parasites consume it.  Large-bodied parasites, like wolves, are macro-parasites.  Wolves kill their hosts.  Micro-parasites include bacteria, viruses, and small multi-celled organisms.  If they quickly kill their host, the banquet is short.  A more stable strategy is to simply take a free ride on a living host, like the billions of bacteria that inhabit our guts, share our meals, and don’t make us sick.

In healthy ecosystems, stability is the norm.  Species coevolve, which encourages balance, like the dance of oak trees and squirrels, or the foxes and rabbits.  Balance is disturbed by natural disasters, like when an invasion of organic farmers overwhelms an ecosystem with their plows, axes, and enslaved animals.  A farming community is a mob of macro-parasites that weakens or destroys its ecosystem host over time.  When parasites disturb balance, McNeill calls this disease.  “It is not absurd to class the ecological role of humankind in its relationship to other life forms as a disease.”

The ruling classes in civilizations behave like macro-parasites when they siphon nutrients away from the working class hosts that they exploit.  To survive, the elites must keep enough farmers alive to maintain an adequate supply of nutrients.  Elites rely on violence specialists to protect their host collection from other two-legged macro-parasites, like the bloodthirsty civilization across the river.  In this scenario, the worker hosts are suffering from a type of disease (the elites) that is called endemic, because it allows them to survive.

Disease that kills the host is epidemic.  “Looked at from the point of view of other organisms, humankind therefore resembles an acute epidemic disease, whose occasional lapses into less virulent forms of behavior have never yet sufficed to permit any really stable, chronic relationship to establish itself.”

Our chimp and bonobo cousins continue to have a stable relationship with their ecosystem.  Consequently, there are not seven billion of them.  Like them, our pre-human ancestors evolved in a tropical rainforest, a warm and wet ecosystem with immense biodiversity.  This diversity included many, many types of parasites, and they lovingly helped to keep our ancestors in balance.  Life was good.  “The balance between eater and eaten was stable, or nearly so, for long periods of time.”

Then, some too-clever ancestors began fooling around with technology.  With spears, we were able to kill more prey, and foolishly eliminate many of the rival predators that helped keep our numbers in check.  By and by, our ancestors began leaving Africa, moving into cooler and drier climates.  We left behind many tropical parasites, and explored new lands with far fewer parasites.  We suffered less disease.  We moved into new regions as skilled hunters, and encountered game animals that had no fear of us.  With clever new technology, like clothing and huts, our ancestors could sidestep our biological limitations and survive in non-tropical habitats.

Antelope and tsetse flies are unaffected by the sleeping sickness parasites they carry.  Many species of burrowing rodents live with the bubonic plague bacteria harmlessly.  These relationships are old and stable, but a blind date with a new parasite can be fatal.  With the advent of animal domestication, there were many blind dates.  We began living in close proximity to other species, and their parasites, to which we had no immunity.  This gave birth to the deadly new diseases of civilization, and led to a long era of epidemics.

“Most and probably all of the distinctive infectious diseases of civilization transferred to human populations from animal herds.”  Aborigines, who did not enslave herd animals, did not suffer from infectious disease.  The same was true for Native Americans, even those who lived in the densely populated regions of Mexico, Central America, and the Andes.

Humans share many diseases with domesticated animals: poultry (26), rats and mice (32), horses (35), pigs (42), sheep and goats (46), cattle (50), and dogs (65).  In addition to the diseases of civilization are ancient rainforest diseases like malaria and yellow fever, which were introduced to the Americas by the slave trade.

From 500 B.C. to A.D. 1200, as civilizations developed in different regions of Eurasia, each area developed pools of civilized diseases, some of which became quite popular.  India has a wonderful climate for parasites, and it may be where smallpox, cholera, and plague parasites first entered human hosts.  Bubonic plague slammed into a virgin population in the Mediterranean basin.  The plague of Justinian (A.D. 542-543) hit hard, maybe killing 100 million, about half of Europe.

From 1200 to 1500, the isolated disease pools of Eurasia eventually connected with the others, creating one large pool of civilized diseases.  Nomads, like the Mongols, transported parasites back and forth between China and Europe.  Parasites also travelled by ship.  Black Death began in China around 1331.  Between 1200 and 1393, China’s population dropped by half.  The disease arrived in Crimea in 1346, spread across Europe, and killed about a third of the people.  Muslims believed that those killed by the plague were martyrs, chosen by the will of Allah.  They mocked the Christian infidels who successfully limited the spread via quarantines.

Between 1300 and 1700, a number of epidemic diseases became domesticated.  To survive, parasites required a steady supply of new hosts without immunity — these were mostly children.  A population of 500,000 or more was needed to produce enough new hosts to support an ongoing infestation of measles.  If a disease was too virulent, it would eliminate its hosts and die off.  Over time, a number of serial killers softened into childhood diseases, like mumps, smallpox, and measles.

From 1500 to 1700, Old World diseases discovered the New World.  Europeans and their African slaves were walking disease bombs, but they were mostly immune to the parasites they carried.  Native Americans were a virgin population, having no immunity whatsoever to the new parasites, they were blindsided by catastrophic epidemics.  The population of Mexico and Peru dropped 90 percent in 120 years.

Since 1700, science has made great advances in death control (not balanced by equal achievements in birth control).  Vaccinations have been effective in controlling smallpox and polio.  Antibiotics have temporarily provided several decades of relief from a number of infectious parasites.  Sewage treatment and water purification systems have also provided temporary relief, during the bubble of abundant energy.

Industrial society, with its radically unhealthy way of life, has created new diseases of civilization, like cancer and heart disease.  Influenza is a powerful wild card, because it rapidly mutates, sometimes into highly virulent forms.  By the time the vaccines are mass-produced, the pandemic is over.  Many new viral diseases, like Ebola and AIDS, are appearing, as the human swarm meets new and exciting rainforest parasites.

The plague bacterium still lives harmlessly in burrowing rodents and their fleas.  Over the years, it has spread around the world.  By 1940, it was carried by 34 species of burrowing rodents in America, and 35 species of fleas.  By 1975, it was found across the western U.S., and portions of Canada and Mexico.  Black rats are the vector that moves the parasites into humans.  As long as the gas-guzzling garbage trucks keep running regularly, we’ll be safe, maybe.

Modern consumers have had little exposure to epidemic disease, but our elaborate, energy-guzzling systems of death control only provide temporary protection.  Sewage treatment, water purification, effective antibiotics, and industrial agriculture have a limited future in a Peak Energy world.

McNeill, William H., Plagues and Peoples, Anchor Books, New York, 1998.  [1976]

Other reviews of books on health include:  Bird Flu, Epidemics, Health & the Rise of Civilization, The Antibiotic Paradox.

The Antibiotic Paradox

Antibiotics are a family of drugs used to treat bacterial infections, including diseases like the bubonic plague, pneumonia, typhus, cholera, and tuberculosis.  The first antibiotic to hit the market was penicillin, in 1941.  It was soon seen to be a wonder drug, because it saved so many lives.  Prior to antibiotics, there were no effective treatments for many life-threatening diseases — they were incurable.  The new drugs revolutionized the practice of medicine, giving doctors power that had previously been unimaginable.

Of course, every technological miracle has a dark shadow of harmful side effects, unintended consequences, and fatal flaws.  Dr. Stuart Levy described this ominous shadow in his book, The Antibiotic Paradox.  He did an excellent job of explaining a very complicated subject in a manner that ordinary folks could readily comprehend.

Our skin and digestive system are home to far more bacteria than the number of cells in our body.  Sometimes bacteria get under our skin, and reproduce faster than our immune system can kill them.  This is an infection, and infections can sometimes be fatal.

“An antibiotic is a natural substance made by one microorganism that inhibits growth of another microorganism.”  Most antibiotics originated as molds or soil bacteria.  Both friendly and unfriendly microorganisms enjoy reproducing at a phenomenal rate, and they often mutate genetically.  Some of these mutants are drug-resistant, because they can survive contact with one or more antibiotics.  These resistant survivors then proceed to produce large numbers of bulletproof offspring. 

Science has attempted to eliminate resistant strains by developing new forms of antibiotics.  Naturally, the bacteria continued reproducing and mutating until they became resistant to the new super drug in town, sometimes as soon as two years after its introduction.

As fast as science created new antibiotics, infectious bacteria developed resistance to them.  It’s the same story with herbicide-resistant weeds, fungicide-resistant plant diseases, and insecticide-resistant crop pests.  No matter how hard they try, or how much money they spend, scientists will never put Mother Nature in a cage.

There are a finite number of substances suitable for use as antibiotics.  They must be effective, free of serious side effects, and capable of being mass produced.  The low-hanging fruit has already been picked, and inventing new antibiotics is becoming more and more challenging and expensive.

Drug companies are losing interest in creating new antibiotics, because they are not highly profitable.  This is because they usually work very well, curing the patient in a matter of days, ending the need for further treatment.  Drug makers are far more interested in creating medicines that patients have to take for the rest of their lives, because they are goldmines.

Everyone agrees that the problem of antibiotic-resistant disease pathogens will never be solved.  The microbes will inevitably develop resistance to any new pharmaceutical weapon.  It’s only a matter of time.  No amount of money or magic can fix this.  Most antibiotic-resistant pathogens are resistant to more than one antibiotic, or MDR (multiple drug resistant).  Some MDR pathogens are resistant to all drugs, and are uncontrollable.  The magic bullets are losing their spunk. 

We are moving inevitably toward the post-antibiotic world, and we are doing little to delay this.  Indeed, the way we are using these drugs is speeding us toward the end of their usefulness.  Many forms of antibiotic use result in increased profits, and we are far more interested in profits than in the future.

The more we use antibiotics, the faster resistance develops.  If our main objectives were to protect human lives, and to delay the arrival of the post-antibiotic era, we would limit their use to treating sick humans.  Doctors would quit giving antibiotics to patients suffering from colds or flu, no matter how loud they whine, because these drugs are useless against viral diseases.  The misuse of antibiotics by doctors is widespread.

The US produces 50 million pounds of antibiotics annually, and about 70 percent of them are given to livestock and poultry.  Most of the drugs given to animals are not to treat disease, but to prevent disease, and to make them grow bigger and faster.  Typically, the drugs pass through the animals in active form, in their manure, and persist in the environment.  The manure is often spread on fields where food crops are grown.  Some of the drugs run off the farm and into drinking water and fish. 

Antibiotics are also used on dogs, cats, fur-bearing animals, shellfish, aquarium fish, fish farms, horses, fruit trees, palm trees, ornamental plants, honey bees, potatoes, tobacco, peppers, tomatoes, and celery.  The drugs are everywhere, and wherever they are, they promote drug resistance.  MDR pathogens are also literally everywhere.

The world of microorganisms is a spooky place.  There are harmless bacteria that are MDR, and they can transfer their drug-resistant characteristics to disease-causing bacteria.  Genetic material is readily exchanged between different types of microbes.

In one experiment, a calf was given a marked variety of E. coli bacteria.  Before long, the bacteria were found in nearby mice and flies.  It spread to pigs, chickens, and turkeys living at a significant distance from the calf.  Humans on the farm began excreting the E. coli. 

Antimicrobial hand soaps provide no real protection, and may actually be harmful.  After the collapse of the Soviet Union, we discovered that rates of allergies and asthma were far lower in Eastern Europe, an environmental disaster area.  Some theorize that reduced hygiene inspires healthier immune systems, because they get regular “exercise.”  Being too tidy may be unhealthy.

Levy’s objective was to publicize the problem of antibiotic misuse.  If we used them with great care, then we could extend their usefulness in treating human diseases.  The future of antibiotics is highly uncertain, but Levy is not out to scare us.  He suspects that we might not experience a complete antibiotic wipeout in the “foreseeable future” (a fuzzy timeframe). 

But the danger is real and substantial.  MDR pathogens are now very common.  “This situation raises the staggering possibility that a time will come when antibiotics as a mode of therapy will be only a fact of historic interest.”  Optimists can celebrate the notion that when antibiotics become useless, far fewer people will die from cancer and heart disease.

Our wild ancestors experienced far less infectious disease because they lived in small, isolated groups.  They didn’t live in close contact with other species, nor did they congregate in filthy cities.  By living in their traditional, time-proven manner, they remained healthy, and had no need for wonder drugs.

Levy, Stuart B., M.D., The Antibiotic Paradox, Second Edition, Perseus Publishing, Cambridge, Massachusetts, 2002.