From the stone age to the Neolithic asthma did not exist

While preparing to travel to Mexico, I often thought about another trip to a place where asthma does not exist: the Bolivian Amazon. Anthropologists Michael Gurven of the University of California at Santa Barbara and Hillard Kaplan of the University of new Mexico in Albuquerque are studying a tribe of plant growers cimane, which lives in the Western part of the Amazon basin. Members of this tribe live mainly due to the fact that give them the jungle. They hunt monkeys, tapirs and other animals with bows and arrows. (Some members of the tribe have the rifle and love to use them, however, because the money in the tribe appear very infrequently, they often simply out of ammo.) Tsimane fish with dams, poisonous plants and special arrows. Although the tribe actively communicates with Bolivians of the XXI century, their way of life is so close to the way of life of the stone age, as you can expect today. That’s why Gurven and Kaplan work here.

I met Gurven at his clinic on the outskirts of the bustling, dusty city of San Borja, on the Bolivian plain. There was a football field nearby where horses grazed. Beautiful cows with sand-colored hair wandered around. From time to time pigs ran by.

Gurven is a representative of the school of anthropology known as the ecology of human behavior. The tools he uses are taken from biology; the innovation is that he uses them in anthropology. According to Gurven, behavioral ecology did not arise as a consequence of cultural anthropology of the early and mid-twentieth century (in particular, Margaret Mead and her study Coming of Age in Samoa), but as a result of the subsequent period of disturbing introspection. Was the very concept of the study of man imperialist and exploitative? Could an outsider really understand another person, or was Margaret Mead doomed to constantly project herself to the participants in the study?

As Gurwen and his students explained to me later, sitting around the campfire in the evenings, the application of behavioral ecology to the study of people begins in a certain fatigue, not necessarily due to a critical assessment of their actions, no matter how justified it may be, but also in connection with the refusal even of attempts to understand those who live in other worlds. Yes, projection is inevitable, but people who continue to live the way we all once lived can teach us a lot, and there are objective ways to evaluate this process. Moreover, all those who are interested in lessons of this kind should hurry up: now there are still hunter-gatherers and plant growers in the world, but this is not for long.

In the tsimane tribe, Gurwen first studied reciprocity and altruism — why people help each other, living in a world with limited resources. He raised the following questions: how does a sick person get help where there is no health insurance? And why do people help the sick if it costs them precious time and energy? In addition, Gurven analyzed how people age in conditions of almost constant onslaught of infection. Even in such an environment, people live for decades after the end of childbearing age. According to the strictest interpretation of Darwin’s theory, this simply should not be. However, in the case of Homo sapiens, this is exactly what happens. What are these additional decades for?

As part of its agreement with tsimane, Gurven provides free medical services to members of the tribe. He transports tsimane from remote villages along the tributaries of the Maniki river to his clinic, where they are examined by a doctor. Laboratory workers take samples of feces, urine and blood from members of the tribe. In a darkened room ultrasound machine examines their hearts and arteries. We will return to Gurwen’s conclusions later, and here we should mention this: he almost accidentally discovered the fact that the immune system of a plant grower living on the Amazon does not work like the immune system of the average resident of London or new York.

Over the past decade, Gurven’s clinic has examined more than 12,000 patients, mostly from the tsimane tribe. In the course of the 37,000 examinations conducted by the employees of Gurven (who examined the patient several times), there was not a single case of asthma. With similar surveys in the US or the UK, a minimum of 1,000 asthma cases could be expected. With regard to autoimmune diseases, fifteen cases were found, including eleven cases of vitiligo (a disease in which the immune system activates skin cells that produce pigment), as well as one case of lupus (skin tuberculosis) and one case of rheumatoid arthritis. If autoimmune diseases were as common in this area as in developed countries, Gurwen would have found about six hundred cases. In other words, among tsimane, the prevalence of autoimmune diseases is one-fortieth of the corresponding figure in new York.

What gurwen really sees is a lot of infections that kill half the members of the tsimane tribe. (Accidents and violent deaths account for another 14%.) And the parasites there are so common that they have become something quite ordinary. Many of tsimane there are giardiasis and amoebiasis. Some suffer from tuberculosis. Some members of the tribe suffer from chronic leishmaniasis, the causative agent of which is the flesh-eating parasite Leishmania. And almost all tsimane have ankylostoma.

In addition, Gurven sees the consequences of active life: many cases of uterine prolapse as a result of multiple births (women of the qimane tribe have an average of nine children), as well as hernias from hard work. However, in the tribe there are no diseases of civilization, such as breast cancer, prostate, ovaries, colon and testicles. The same can be said about cardiovascular diseases.

Maybe the members of the tribe zimane — especially people with a genetic immunity? Other researchers Amerindians of the Amazon, are at a primitive level of cultural development, also found the lack of allergic diseases and other common in our days diseases. Maybe the Amerinds are not affected by these diseases at the genetic level? Possible, but unlikely. Similar observations among different population groups in Europe, Africa and Asia have shown that people living in more “dirty” environments suffer less from allergic and autoimmune diseases. The opposite is true: anyone who lives in the right conditions is likely to develop asthma. Such conditions take place, for example, in new York, London and Sydney.

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