Of course, the absence of crowd diseases from small populations of hunter-gatherers does not mean that hunter-gatherers are free from infectious diseases. They do have infectious diseases, but their diseases are different from the crowd diseases in four respects. First, the microbes causing their diseases are not confined to the human species but are shared with animals (such as the agent of yellow fever, shared with monkeys) or else capable of surviving in soil (such as the agents causing botulism and tetanus). Second, many of the diseases are not acute but chronic, such as leprosy and yaws. Third, some of the diseases are transmitted inefficiently between people, leprosy and yaws again being examples. Finally, most of the diseases do not confer permanent immunity: a person who has recovered from one bout of a disease can contract the same disease again. These four facts mean that these diseases can maintain themselves in small human populations, infecting and re-infecting victims from animal and soil reservoirs and from chronically sick people.
Hunter-gatherers and small farming populations are not immune to crowd diseases; they are merely unable to maintain crowd diseases by themselves. In fact, small populations are, tragically, especially susceptible to crowd diseases when they become infected by a visitor from the outside world. Their enhanced susceptibility is due to the fact that at least some of the crowd diseases tend to have higher fatality rates in adults than in children. In dense urban First World populations everyone (until recently) became exposed to measles as a child, but in a small isolated population of hunter-gatherers the adults have not been exposed to measles and are likely to die of it if it arrives. There are many horror stories of Inuit, Native American, and Aboriginal Australian populations being virtually wiped out by epidemic diseases introduced through European contact.
Responses to diseases
For traditional societies, diseases differ from the other three major types of dangers as regards people’s understanding of the underlying mechanisms, and hence of effective cures or preventive measures. When someone is injured or dies from an accident, violence, or hunger, the cause and underlying process are clear: the victim was hit by a falling tree, struck by an enemy’s arrow, or starved by insufficient food. The appropriate cure or preventive measure is equally clear: don’t sleep under dead trees, watch out for enemies or kill them first, and ensure a reliable food supply. However, in the case of diseases, sound empirical understanding of causes, and science-based preventive measures and cures, achieved notable success only within the last two centuries. Until then, state societies as well as traditional small-scale societies suffered heavy tolls from disease.
This is not to say that traditional peoples have been completely helpless at preventing or curing diseases. The Siriono evidently understand that there is a connection between human feces and diseases such as dysentery and hookworm. A Siriono mother promptly cleans up her infant’s feces when it defecates, stores the feces in a basket, and eventually dumps the basket’s contents far away in the forest. But even the Siriono are not rigorous in their hygiene. Anthropologist Allan Holmberg relates watching a Siriono infant unobserved by his mother defecate, lie in his feces, smear them over himself, and put them into his mouth. When his mother finally noticed what was going on, she put her finger into the baby’s mouth, removed the feces, wiped but didn’t bathe the filthy baby, and resumed eating herself without washing her hands. Piraha Indians let their dogs eat off the plates from which they themselves are simultaneously eating: that’s a good way to acquire canine germs and parasites.
By trial and error, many traditional peoples identify local plants which they believe help cure particular ailments. My New Guinea friends frequently point out to me certain plants which they say that they use to treat malaria, other fevers, or dysentery or to induce miscarriage. Western ethnobotanists have studied this traditional pharmacological knowledge, and Western pharmaceutical companies have extracted drugs from these plants. Nevertheless, the overall effectiveness of traditional medical knowledge, interesting as it is, tends to be limited. Malaria is still one of the commonest causes of illness and death in New Guinea’s lowlands and hills. It was only when scientists established that malaria is caused by a protozoan of genus Plasmodium transmitted by mosquitoes of genus Anopheles, and that it can be cured by various drugs, that the percentage of New Guinea lowlanders suffering malaria attacks could be reduced from around 50% to below 1%.
Views of disease causes, and resulting attempted preventive measures and cures, differ among traditional peoples. Some but not all peoples have specialized healers, termed “shamans” by Westerners, and given specific epithets by the people involved. The !Kung and the Ache often view illness fatalistically, as something that is due to chance and can’t be helped. In other cases the Ache offer biological explanations: e.g., that fatal intestinal illnesses of children are due to weaning and eating solid food, and that fevers are caused by eating bad meat, too much honey, honey unmixed with water, too many insect larvae, or other dangerous foods, or by exposure to human blood. Each of these explanations may sometimes be correct, but they don’t serve to protect the Ache from a high death rate from disease. The Daribi, Fayu, Kaulong, Yanomamo, and many other peoples blame some illnesses on a curse, magic, or a sorcerer, to be countered by raiding, killing, or paying the responsible sorcerer. The Dani, Daribi, and !Kung attribute other illnesses to ghosts or spirits, with whom !Kung healers attempt to mediate by going into a trance. The Kaulong, Siriono, and many other peoples seek moral and religious explanations for illnesses: i.e., the victim brought the illness on himself by an oversight, committing an offense against nature, or violating a taboo. For instance, the Kaulong attribute respiratory illnesses of men to pollution by women, when a man has made the dangerous mistake of coming into contact with an object polluted by a woman menstruating or giving birth, or when a man has walked under any fallen tree or bridge or has drunk from a river (because a woman might have walked on the tree, over the bridge, or through the river). Before we Westerners look down on those Kaulong theories of male respiratory disease, we should reflect on the frequency with which our own cancer victims seek to identify their moral responsibility or the cause for their cancer, whose specific cause is as obscure to us as is the cause of male respiratory illness to the Kaulong.
Starvation
In February 1913, as the British explorer A. F. R. Wollaston was descending in good spirits through New Guinea montane forests after having succeeded in reaching the snow line on New Guinea’s highest mountain, he was horrified to find two recently dead bodies in his path. Over the next two days, which he described as among the most awful of his life, he encountered over 30 more bodies of New Guinea mountain people, mostly women and children, singly or in groups of up to five, lying in rough shelters along the track. One group consisting of a dead woman and two dead children included a still-living small girl about three years old, whom he carried to his camp and fed with milk but who died within a few hours. Into camp came another group of a man, a woman, and two children, of whom all except one of the children expired. The whole group, already chronically malnourished, had exhausted their supplies of sweet potatoes and pigs and found no wild food to eat in the forest except the hearts of some palm trees, and the weaker ones apparently died of starvation.
Compared to accidents, violence, and disease, which are frequently recognized and mentioned as causes of death in traditional societies, death due to starvation as witnessed by Wollaston receives much less mention. When it does occur, it is likely to involve mass deaths, because people in small-scale societies share food, so that either no one starves or else many people do simultaneously. But starvation is greatly underappreciated as a contributing cause of death. Under most circumstances, when people become seriously malnourished, something else occurs to kill them before they die purely of starvation and nothing else. Their body resistance fails, they become susceptible to illness, and they are recorded as dying of a disease from which a healthy person would have recovered. As they become physically weak, they become more prone to accidents such as falling from a tree or drowning, or to being killed by healthy enemies. The pre-occupation of small-scale societies with food, and the diverse and elaborate measures to which they resort to ensure their food supply and which I shall explain in the following pages, testify to their omnipresent concern with starvation as a major risk of traditional life.