Consumption (52 page)

When I left the Arctic, in 1992, there were then active epidemics in the hamlets of Coral Harbour and Arviat. Five years before that it was Repulse Bay; a few years before that, Chesterfield Inlet. The historic exposure rate is so high that TB outbreaks can be expected to arise from reactivated latent disease for decades to come.

It is difficult to overstate the menace that
Mycobacterium tuberculosis
is to humans. Like a storm forming from the coalescence of several different weather systems, it is the perfect pathogen in many respects: it has a long latent asymptomatic phase, allowing it to dwell on in populations; it spreads invisibly, in the air; and when it takes hold it erodes every single organ system:
the brain, kidneys, the gut, as well as its principal residence, the lungs. Its perfection is preserved most of all by its ability to shrug off our poisons.

In North America we imagine this to be a disease on the margins—of history and geography. But the story of HIV is illustrative: suffering does not localize. Trouble on the edges moves to the centre. The economy globalizes and, at the same instant, so does our epidemiology. Strains of resistant super bugs, tuberculosis isolates resistant to all known medications, are identified in Russian jails and six weeks later they show up in Brooklyn. Our reacquaintance with the old antagonist is already well underway. And, whether we like or not, we return to this problem that so preoccupied our grandparents.

The idea of latency is worth thinking about. Biology rewards patience.
Mycobacterium tuberculosis
understands this. It establishes its toeholds and then it becomes dormant. And in this restraint it demonstrates the full extent of its power. It is not necessary that every thirst be slaked. In not acting upon a desire, that desire is diminished neither in intensity nor in merit. Priests fall in love with parishioners and display it all the time—we read about this in the newspapers. What we do not read about are the times, over and over again, when those words are not said, those kisses are not offered, or solicited. But such unexpressed love does not amount to nothing. When we love it is because we have seen especially clearly. And a clear view of human beauty is a treasure that endures for as long as the possessor of such insight breathes. And endurance is the final measure of importance: of ideas and of organisms. Love lies latent sometimes, as tuberculosis does—but, as any epidemiologist will tell you, latent is nothing like gone.

She used to obsess over whether her children had
puvaluq
. Everyone she saw—the nurses and the other doctors who worked with me there—who didn’t know her story dismissed her worry with a wave. They were all from the south, those shining faces, where the creature had been pushed away, for a little while. How could they know?

Omran’s Curse, or the Fifth Phase of Epidemiologic Transition

One evening in 1973 I took one of the medical journals to which I subscribed home with me from the clinic where I worked in Rankin Inlet. I liked to spend the evenings reading about far-off developments in the hospitals I had trained in—it made the isolation a little less acute and made me feel a little less like an imposter. It was my first job and every day I wondered when someone was going to see right through me. (This is not a concern that was ever entirely resolved.)

I read late into the night, about the utility of beta blockers and bile salt sequestrants. Just as I was about to go to bed, I came upon Abdel Omran’s paper advancing the idea of the epidemiologic transition. The next time I looked up from the page it was dawn, and I had come to understand human illness and history in a way I had never considered before. I was like a second-year sciences student coming to terms with relativistic motion. I knew how physicists must have felt at the beginning of the last century when the patent clerk had started publishing in obscure journals.

Omran’s epidemiologic transition rests on the idea that the way we live is revealed fundamentally by how we sicken and die. When changes occur in the way we eat and fight and raise our children that are truly important, then they always show up in the way we die.

The skeletal remains of paleolithic humans bear the stigmatae of the threats they faced while living: skulls scored with teethmarks, fractured long bones and necks, and the hallmarks of starvation: pitiably small children lying
with older adults. The marks on those bones are the clearest indicators we have about what those lives were like. From them, we learn that there was always a struggle to find enough food and all around there were predators—great cats and wild dogs looking to pull us down by our necks. For millions of years, humans died mostly of those two causes and what we adapted ourselves to was bleeding, and hunger. Six million years we spent walking on the Serengeti, living and dying that way. The Inuit lived exactly like this until the Second World War, walking and hunting and keeping an eye out for bears. Many of the old men I treated claimed to still long for that harder life, and the dignity they thought it lent them.

When humans began planting seeds—initially in Mesopotamia—everything changed. We grouped together for the first time in stationary villages, in numbers that no hunting-gathering society could support. We domesticated animals and produced enough farmed food to support specialists: potters and metalsmiths, priests and soldiers. One effect of all this was that, grouped together in cities and towns, humans become vulnerable to infections in a way we had never been as wanderers.

Nomads suffer no epidemics because they are dispersed, their populations too small to sustain a cycle of infection. A society smaller than half a million people, for instance, is not able to sustain endemic measles and consequent population-wide immunity. When pathogens enter a small population, everyone dies or becomes immune at once. Mostly what they do is die. The Icelanders demonstrated this, to their great cost, when North Atlantic trade resumed after the Dark Ages.

Indeed, the only transmittable infections of any sort that hunter-gatherers suffer from are insect-borne—malaria especially, but also dengue fever, yellow fever, and the various encephalitides. The Inuit, whose mosquitoes were frozen solid every September, suffered from no transmittable infections at all. None. This was subsequently to change.

With the Neolithic revolution, tuberculosis learned to infect humans, and within the crowded little homes of the early farmers it became as ubiquitous as the rodent vermin that adapted itself similarly and moved in off the fields to seek out man and his leavings. We find the evidence in the bones that are
dug up, the cold abscesses and the characteristic patterns of osseous infections. Influenza leapt to us from wild birds, and syphilis from the unlucky sheep domesticated by Neolithic farmers.

These were all features of the second phase of the epidemiologic transition, a change that revolved around the development of agriculture, a time that also saw the rise of tyrants and of armies. Permanent populations adjacent to cultivated fields could spare enough men to send off to war. Hunters and gatherers living alongside these civilizations simply melted back into the trees and were progressively confined to non-arable spaces. Still, their bones are revelatory: the nomads were better fed in their less-organized bands than the peasants of the settled tribes, whose populations expanded in Malthusian fashion to the limits of supportability as rapidly as the food supply grew. And it is the civilized bones that bear the marks of sword cuts and shackles—seen nowhere among the hunters, for whom war is always a relatively non-lethal pastime.

These were the prevailing circumstances from the rise of the Mesopotamian civilizations to, in Western Europe, the early nineteenth century. Life expectancy remained about forty years throughout this period, in every society. The principal causes of death were TB, homicide, dysentery, starvation, and, beneath fifty degrees of latitude, malaria.

What changed everything, ushering in the third phase of the epidemiologic transition, was the rise of engines. For Europeans this corresponded to the Industrial Revolution. As both agricultural and manufacturing techniques industrialized, the population movement into cities and off the fields coincided with a rise in availability of mass-produced food and with increasing crowding in the tenements. Accompanying this movement was an unprecedented human exposure to chemical toxins, the appearance of occupational lung disease, an increase in the consumption of animal fats, and a decrease in fibre intake. Tobacco and alcohol use became significant limiters of health too. The Dickensian horror that was Victorian London was replayed in successive years in Berlin and Paris and Ankara and St. Petersburg. Following these: Delhi and Mexico City and Beijing. Bodies mangled in
industrial and road accidents while food comes in from the countryside at a steady clip. Tired workers stumbling home to gorge themselves on cheap manufactured food.

The diseases of affluence—heart disease, cancer—gained a foothold then, and for the first time there were important threats to humans other than starvation, violence, and infections. One of the most important insights gained through examining the epidemiologic transition is this: there is nothing inevitable about the sicknesses of our time. Heart attacks are not just what happens to people who manage to survive into their fifties and sixties. Before the Industrial Revolution, coronary thrombosis, as heart attacks were initially called—myocardial infarctions, as they are called now—had not been described. By this time, vaccination for rabies and smallpox had been developed; the causative organisms for malaria and tuberculosis had been identified; the developments of aseptic surgery and anaesthesia made operations survivable. Medicine was young but not blind. Heart attacks were unknown because they hardly ever happened, even among those who lived to be old. Before bleached flour became widely available, at the beginning of the eighteenth century, colon cancer was as rare as it is in Africa now. Throughout the Industrial Revolution, as it unfolded in Europe, and a century later, in India and China, these illnesses have appeared with monotonous predictability. Cancer and heart attacks and strokes are what will most likely kill anyone wealthy enough to know what those words mean. Alongside these ran the infections, especially tuberculosis, but before useful treatment was developed the death rate was already falling, as apartments and houses became less crowded and the food supply more reliable. Violence continued, of course, and the homicidal spasm of the first half of the twentieth century was like nothing else history has seen. Food may pacify hungry babies and holiday diners, but it does not soothe the martial instinct of nations.

The fourth phase of the epidemiologic transition began after the Second World War. It saw the dramatic impact of medical therapies such as antibiotics on infant mortality. With these, and better obstetrical care, life expectancy soared by two years per decade, to the mid-eighties, in Japan and
Scandinavia. For Asian and South American societies, the fourth phase trailed, but not by much. These treatments are cheap and so these technologies—especially the vaccines—have been readily exported to developing nations. From this point forward, a certain amount of overlap exists between societies at varying levels of affluence. Populations may be affected by the availability of antibiotics and vaccinations while they are still dependent on subsistence farming. Starvation may persist notwithstanding the (imminent, and astounding) eradication of polio.

The effect of antibiotics, even on the rich societies, is difficult to overstate. Long lists of sanatoria closed as consumptives regained their colour and were pushed out into the world. Heart disease and stroke, increasingly important killers since the advent of the cotton gin, began to decline in lethality in the mid-1950s, when it became possible to treat hypertension. Cancer deaths, too, have declined under the weight of billions of dollars worth of research and therapy. Health care in America now consumes three times as much wealth as the military. One hundred years ago it was one-tenth, but in those days, babies whooped themselves to death every night in every neighbourhood, and now they do not.

Our prosperity has grown enormously in this time; we have become richer even more quickly than our riches have made us sick. Our wealth has allowed us to hold at bay the diseases of affluence, allowed us to believe that we are becoming innately more healthy. Look at our children’s height and the robustness of their aligned incisors. The old idea of the essence emerges; the Victorian consumptive’s TB was an expression of himself. We are taller and more long-lived, we assume, because we are essentially stronger and, one supposes, cleaner. It is the centrepiece of Omran’s idea. The Greeks wrote plays about this sort of thinking.

Although Omran did not describe it, a fifth phase of the epidemiologic transition is becoming evident now. As death rates from vascular disease have declined under the effect of beta blockers, cholesterol-lowering drugs, and ACE inhibitors, every developed society in the world has grown fatter. And for those who are fat enough to develop diabetes and the metabolic
syndrome that is its precursor (40 per cent of adult North Americans), there has been much less progress made in the mortality rate from heart attacks.