Africa, African Diseases, and the Creation of Black African Slavery

 Jonathan Kennedy has provided a fascinating reconstruction of human history in his book Pathogenesis: A History of the World in Eight Plagues.  In his perspective, historical inflection points have often been driven by the interactions of populations with raging microbial infections.  An internal plague can cause great loss of life and significant societal changes.  Introduction of a microbial infection by another society or group has often given the decisive advantage not to the strongest but to the group best able to withstand the infection.  The most immediate example of the latter arises in American history where North and South America each had sophisticated indigenous populations when they were invaded by European colonialists.  The natives had not developed the same diseases as those that had become endemic in European societies.  Consequently, loss of life was enormous in American societies and a small number of invaders was easily able to conquer and control the American continents.  In some cases, the original inhabitants disappeared entirely.

European colonialists managed to set up colonies and dominate native societies in Asian countries and Oceanic nations.  However, parts of Africa were long too dangerous for Europeans to enter because in that case the endemic African microbial diseases were too deadly to allow an invasion.  In the 1400s the Portuguese began trying to form colonies in West Africa where they knew gold could be found.  They could only operate on the coastlines and were never able to survive for long in the interior. The relevant diseases that Africa harbored were malaria and yellow fever.  Both were mosquito delivered.  Malaria existed in a number of countries with hot, humid regions.  The damaging plasmodium parasite produced by mosquito bites came in different forms.  The form common in Africa, falciparum malaria, is the deadliest.

“Falciparum malaria thrives in the tropical climates.  Anopheles gambiae mosquitoes lay their eggs in standing water, and there is plenty of this in wet and humid West Africa.  Consequently, malaria was so widespread in West Africa that it would have been almost impossible to avoid being bitten by infected Anopheles mosquitoes.  Innate immunity provides nowhere near full protection.  Even today, malaria kills hundreds of thousands of people in sub-Saharan Africa every year, most of them young children exposed to the disease for the first time.  Those who don’t die in childhood can be reinfected and harbor the plasmodium, but as one’s body develops resistance it is rare to show anything more than mild symptoms.  Malaria, then, is a relatively harmless condition among adults who have lived in West Africa all their lives.  In contrast, Plasmodium falciparum is deadly to adults who haven’t grown up in a region where it is endemic, and a significant proportion of European would-be settlers were killed by malaria soon after they arrived.”

“Yellow fever is also common in West Africa, but the epidemiological dynamics are different.  The virus tends not to be deadly in childhood, and after one infection you have lifelong immunity and can never again serve as a host to the pathogen.  But yellow fever is a very serious disease for adults…About one-third of those who develop symptoms die.”

“Despite the differences between malaria and yellow fever, the outcome was the same from the perspective of Europeans: they were killed in horrifying numbers, while the adult population of West Africa appeared unaffected.”

This threat of death would keep much of Africa off limits for hundreds of years.  While the interior was impenetrable, interactions, including trade could occur on the coast.  One trade that would develop was that for African slaves.  As it happened, the ability to ignore the threat of malaria and continue working made Africans convenient slaves in the American colonies.  The understanding of immunity did not exist, allowing the interpretation of this feature as being somehow characteristic of natural born slaves: strong workers but inferior humans.  Eventually the Bible would be wheeled out to justify Black enslavement as God’s will.  Even after slavery came to an end this perception of black Africans had to be maintained in order to justify the American Jim Crow South and the continued colonial domination of African peoples.

Kennedy provides this perspective. 

“The history of slavery goes back far beyond the European colonization of the Caribbean.  It emerged soon after the adoption of settled agriculture and should be conceptualized as the extension of the logic of domestication of animals to unfortunate members of our own species.  When men and women became slaves they were no longer treated as fellow humans but as beasts of burden.  They could be held in captivity, worked to the point of exhaustion, beaten into submission, and exchanged for something else.  But there was something new and peculiar about American slavery.  For thousands of years, skin color had no bearing on who was seen as a suitable candidate for enslavement.  It was in the Americas that people of African origin became associated with servitude for the first time.”

The earliest setters in the New World were the Spanish and Portuguese.  Many of the locations colonized were ideal for cultivating crops of sugarcane. Indigenous natives were either few, or if once many, were decimated by the encounter with European diseases.  Slave labor was necessary, and Africans seemed the best option.

“The early conquistadors’, decision to use enslaved Africans on their sugar plantations had unexpected but momentous consequences: it inadvertently sent the whole of the American tropics on an inescapable path toward racialized slavery because the nascent transatlantic slave trade carried not only people but also some of the mosquitos and microbes that made West Africa a deadly place for Europeans.” 

“The arrival of West African pathogens turned the Caribbean into a new white man’s grave.  Yellow fever epidemics rather than malaria were the major killer of Europeans, but the basic outcome was the same: almost everyone who had grown up in West Africa would have been exposed to yellow fever and acquired lifelong immunity, whereas new settlers from Europe hadn’t developed any tolerance and so died in droves.  As a result, African labor became the economically ‘rational’ option for plantation owners.”

When British colonialists began plantations in the Caribbean, they attempted to establish their traditional use of indentured British workers to perform the necessary labor under short-term contracts.  However, the African pathogens had already made their way to those areas.  Again, the only economically rational path was to switch to the enslavement of Africans.  This practice would next move to what is now the United States.  Initially all the colonies accepted slavery as a legal institution.  After the revolution and the founding of the United States, the northern states would gradually pass laws eliminating slavery, while it became entrenched ever more firmly in the southern states.  Kennedy points out that malaria was the dominant pathogen, and it needed a warm climate to exist.  Slavery of Africans provided no advantage in the northern states.  For them it was more efficient to get the needed labor from European immigrants, a new version of traditional British indentured servitude.  And thus began the North-South polarization that continues to this day.

It was only the discovery and determined application of quinine as treatment for malaria that would convince Europeans that they could invade sub-Saharan Africa and live long enough to extract wealth from it.

“In the natural world, quinine is found in the bark of cinchona trees that grow in the eastern foothills of the Andes.  In the late 1500s, Spanish Jesuits observed indigenous people treating fever with a kind of proto-tonic water that consisted of ground bark mixed with sweetened water.  By the middle of the seventeenth century, ‘Jesuit powder’ was used across Europe as a treatment for malaria, which was endemic to much of the region at the time—albeit mostly the milder vivax strain that was able to reproduce at colder temperatures.”

For access to inner Africa, it would take much longer for quinine to become used because it would provide no protection from yellow fever infections and the science was not available to separate that disease from malaria.

“In 1854, an iron-hulled steamboat—the Pleiad—traveled up the Niger on another Navy-sponsored expedition.  The only significant difference between this mission and the one that took place in 1841-42 is that everyone on board took doses of quinine.  It turned out to be an unprecedented success, penetrating farther into Africa than any Europeans had done before and returning to the coast without losing a single member of the crew.”

“Five hundred years after Portuguese explorers had first coveted Africa’s vast natural resources, settler mortality fell to a level that made colonialism possible.”

The threat of disease and death was not eliminated, but it changed the nature of the colonial invasion of Africa, or, in Kennedy’s term, the “Scramble for Africa.” 

“The continued threat posed by infectious diseases in tropical Africa had an enormous impact on the specific form that colonialism took.  The region attracted ambitious and unscrupulous Europeans motivated by making as much money in as little time and with as small a capital expenditure as possible—and then cutting and running before they were struck down by the disease.  They weren’t colonial settlers.  So, unlike in New England, they didn’t bring their families with them, settle down and build institutions in the image of their home country.  Rather, the Europeans who colonized Africa in the last decades of the nineteenth century created ‘extractive institutions’ that used violence and the threat of violence to coerce the population into mining natural resources and transporting them to the coast, where they were shipped to Europe.  The ultimate aim of this brutal endeavor was not to build a new and better society, but to enrich a small group of Europeans by draining wealth from the region.”

Kennedy uses the Belgian King Leopold’s formation and management of the “Congo Free State” as his example of the European invasion.

“According to the American writer Adam Hochschild, when the Congo Free State was created in 1885 it had about 25 million inhabitants; by 1923, when the rubber boom was over, there were 7.7 million.  For every 10 kilograms of rubber exported, the population fell by one.  Congolese didn’t only die as a direct result of the Force Publique’s violence: Belgian rule caused massive disruption to the lives of people living in Central Africa, leading to famines and plummeting birth rates.  As soldiers, caravans of porters, steamboat crews and displaced people moved across the colony they spread diseases from the coast to the interior where many communities had lived relatively isolated existences prior to the Belgians’ arrival.  Half a million people died from sleeping sickness in 1901 alone.  Smallpox was another major killer.  One observer visiting a smallpox-ravaged village in which the vultures had become so fat on their diet of human flesh that they were unable to fly.”

“Even after the Congo became independent in 1960, half a century after Leopold’s death, the impact of colonialism lingered.  In contrast to North America, where the colonial legacy was democracy and rule of law, in the Congo, it was authoritarianism and plunder.”

“The [Congo] is a typical story—albeit an extreme version—for the nations that were created in the Scramble for Africa at the end of the nineteenth century and won their independence in the second half of the twentieth.  The ten poorest countries in the world are all former colonies in sub-Saharan Africa.  It is not unreasonable to conclude that these societies would have been better off if Europeans had never discovered a moderately effective treatment for malaria and the region had remained a white man’s grave.”

It seems Africa was made to pay a price for thwarting European greed for such a long period.  The people of Africa would also pay a price for being blessed with an apparent ability to ignore malaria.  They would become the slave of convenience because they could work where malaria was a risk to Europeans.  They would soon become the slave of Biblical destiny as Europeans and their descendants sought moral justifications for the enslavement and mistreatment.

This tale is certainly consistent with Kennedy’s claim that the microbial stew in which we humans exist has had much to do with determining who we have become.  It almost justifies the following comment he provided.

“It is no exaggeration to say that bacteria have made the planet habitable for complex life, including humans.  It’s a bacterial world, and we’re just squatting here.”

 

Pathogenesis: Placing the Human Population in a Global Perspective

We humans like to think of ourselves as masters of our destiny and as having dominion over the planet.  To counter such foolishness, Jonathan Kennedy has presented a somewhat different perspective in his book Pathogenesis: A History of the World in Eight Plagues.  He presents a fascinating and compelling retelling of our history and Earth’s history where the main players are the microbes that fashioned the planet into a platform that would allow the development of complex life forms.  We humans are the offspring of those microbes.  Having evolved in a microbial soup, these microorganisms (including viruses) are a part of who we are and have continuously altered our development and our history.

First, Earth had to be made hospitable to advanced life forms.  Oxygen provides the fuel complex life forms require.  It is a highly reactive element, and the early earth would have little free oxygen.  Our planet formed about 4.6 billion years ago.  Evidence of microbial life forms appeared about a billion years later. 

“About 2.5 billion years ago our world was almost completely submerged in water, with the exception of the odd volcanic peak piercing through the sea.  Methane in the atmosphere created a greenhouse effect that kept the planet far hotter than it is today.  There was little or no free oxygen in the water or air, as it was all locked up in other molecules.  Life on earth consisted of anerobic bacteria.  Then the world began to change with the emergence of cyanobacteria—blue-green algae that used the sun’s rays to power photosynthesis.  This made cyanobacteria much more effective at generating energy, giving them a huge evolutionary advantage.  Their numbers boomed.  Over a period of several hundred million years, they pumped vast amounts of oxygen—a byproduct of photosynthesis—into the oceans and atmosphere.”

“This Great Oxygenation Event transformed the planet.  Some of the oxygen combined with methane to form carbon dioxide, a much less effective greenhouse gas.  As the planet cooled, ice sheets crept as far as the tropics.  The sea level fell and land emerged from the water.  Eukaryotic organisms appear in the fossil record shortly after oxygen became abundant in the atmosphere.”

“Cyanobacteria in the oceans still contribute to the oxygen in the atmosphere.  In total, phytoplankton—photosynthesizing microorganisms in the sea—account for at least half of the oxygen produced by living organisms.”

The famous paleontologist, Stephen Jay Gould was moved to claim that “bacteria are—and always have been—the dominant forms of life on earth.”

“Bacteria are everywhere.  They have been found in Antarctic glaciers and on the ocean floor where boiling hot water surges out of the center of the earth.  They live miles below ground and miles above it, where they influence the formation of clouds and possibly even lightning.  They are so numerous that, despite their tiny size, the total mass of all bacteria on the planet is thirty-five times that of all the animals and 1,000 times that of all humans.”

To these microbes must be added the ubiquitous viruses that infect the microbes and all other life forms.

“Viruses are tiny, even by the standards of microbes.  They can be hundreds of times smaller than the average bacterium.  Viruses are so minuscule that they haven’t left a mark on the fossil record.  Their origins remain unclear.  They may have emerged prior to, soon after, or even from early single-celled life.  In any event, for most if not all the 3.5 billion years that life has been around, viruses have been capable of infecting it.  They are found everywhere where life is present and far outnumber all forms of life on earth—even bacteria.  A liter of sea water contains over 100 billion virus particles, and one kilogram of dried soil somewhere in the region of a trillion…But only about 220 types of virus are known to be capable of infecting humans.  Most are so-called bacteriophages or phages—from the Greek ‘to devour.’  Phages kill between 20 percent and 40 percent of all bacteria every day, which maintains balance in a variety of ecosystems, from the oceans to our own bodies, by ensuring that no one strain of bacteria can become too numerous.”

Viruses can both maintain and kill life forms.  Somewhat less recognized is the fact that they can alter life forms as well.

“A retrovirus is a specific type of virus that reproduces by inserting a copy of its DNA into the genome of the host cell.  But when a retrovirus infects a sperm or egg cell, something remarkable happens: viral DNA is then passed on to every cell in every subsequent generation.  An astonishing 8 percent of the human genome is made up of such genes.”

Much of this genetic material seems to have no function, but some of it is now recognized as being fundamental in the evolution of life.  Kennedy provides two examples of what scientists now recognize as virus-introduced genetic mutations.  The first is a mutation that occurred about 400 million years ago and provides a role in memory formation.  The removal of a single gene can render mice incapable of forming memories.  The second involves the mutation that allowed offspring to be raised within the body of a female rather than by producing an egg.  This involves creating a placenta with an interface through which the mother and offspring can exchange nutrients while not generating immune responses due to their different genetic makeup—a rather complex construct.

“When geneticists looked at the gene responsible for creating it [the placenta interface], they realized that it was almost identical to those used by retroviruses to produce the proteins that attach to cells they are infecting without triggering an immune response. The scientists concluded that a crucial function of the placenta didn’t emerge gradually as a result of evolution by natural selection but was suddenly acquired when a retrovirus inserted its DNA into our ancestor’s genome.”

This capability can be harnessed by medical researchers using viruses to deliver new genetic material into cells in the field of gene therapy.

The critical role that the microbes play within our bodies requires us to consider them as important to life as any organ upon which we depend.

“Our bodies are absolutely teeming with microscopic life.  Each of us hosts an estimated 40 trillion bacteria—meaning they slightly outnumber human cells.  Viruses? At least ten times that figure.  In total, the human microbiome—all the microbes living in our body—weighs around the same as our brain, between one and two kilos.  The vast majority of these bacteria and viruses don’t make us ill.  In fact, they have evolved with our ancestors for millions of years, forming close and interdependent relationships with one another.  In other words, humans have outsourced some essential tasks to microbes.  This is because bacteria can adapt more quickly to new situations than humans.  While our cells carry between 20,000 and 25,000 genes, the microbiome contains around 500 times more than that.  The enormous number of genes, together with the fact that they reproduce far more quickly than more complex life and are able to transfer genes ‘horizontally’ from one species to another, allows bacteria to evolve much faster than humans.”

Recognizing the critical role of microorganisms in human life drives us to rethink our history in terms of the role human initiative has played and the role microorganisms have played in forcing humans to respond to their initiatives.  We know that microbes can infect us with diseases that are capable of killing a large fraction of the human population.  That has happened numerous times throughout history.  Is it the “fittest” that survive, or those with the strongest immune response.  Do we need to reconsider the nature of evolution?  

Consider one lesson from our recent history.  European societies with dense populations and intimate relations with animal species encountered multiple deadly plagues.  People would eventually develop immunity and the survivors would propagate the society with the dangerous microbes remaining endemic within the population.  These Europeans would then arrive on the American continents and encounter indigenous populations with no experience with those microbes.  The result was enormous loss of life for the natives and a tremendous advantage for the invaders.  A small population was aided by microbes in dominating a much larger indigenous population and taking control of the continents and their future history.  This was a momentous result, but it was by no means a unique occurrence.  Microbes and the diseases they cause would play a great role in how human history evolved.  That is the subject of Kennedy’s book: illuminating how human history has depended on the vagaries of microbial interactions.  His study led him to make the following observation.

“It is no exaggeration to say that bacteria have made the planet habitable for complex life, including humans.  It’s a bacterial world, and we’re just squatting here.”