اهلی‌سازی و آسیب‌ها و بیماری‌های جسمانی در جوامع آغاز نوسنگی ایران

Abstract
According to archaeological findings, the onset of agriculture, permanent settlement in villages, increased labor, dietary changes, and population growth led to a significant rise in diseases and physical traumas among Neolithic humans. Neolithic lifeways carried substantial physiological consequences, marked by the appearance and spread of skeletal lesions that had been rare or absent in earlier foraging societies. These health issues can be broadly categorized as skeletal traumas resulting from shifts in physical activities, oral and dental diseases, anemia caused by dietary changes, infectious and epidemic diseases triggered by population growth (e.g., skeletal tuberculosis), and zoonotic diseases resulting from close cohabitation with domesticated animals. The cultivation and consumption of cereals, which are low in iron, frequently led to iron-deficiency anemia among Neolithic populations. This, in turn, contributed to other skeletal conditions such as porotic hyperostosis and cribra orbitalia. The high carbohydrate content of cereals also contributed to a noticeable increase in dental caries. Another frequent condition of Neolithic populations was osteoarthritis, arising from repetitive and strenuous agricultural labor, particularly tasks such as grinding grain, hoeing, and carrying heavy loads.
Infectious and epidemic diseases became more prevalent due to factors such as increased population density, permanent settlements, close interpersonal contact, and poor hygiene practice factors conducive to the spread of diseases like skeletal tuberculosis. The onset of sedentism and increased proximity to animals also led to the emergence of deadly and epidemic zoonotic diseases such as plague and brucellosis. Although the evidence for these diseases in Iran remains limited and unevenly studied, signs of such conditions have been identified in several Neolithic sites, including Sheikh-i Abad (Sahneh County) and Ganj Dareh (Harsin County) in Kermanshah Province, as well as Hajji Firuz Tepe in Azerbaijan.
Keywords: Domestication, Disease, Neolithic, Social Structure.
Introduction
Around ten thousand years ago, human populations began the domestication of plants and animals. As a result, sedentism emerged, and although some might assume that humans thereby experienced a better life, the reality was otherwise. Food production required continuous hard labor, diets were often nutritionally poor, and life in denser communities—compared with pre-sedentary periods—led to the spread of many diseases. While certain aspects of living conditions improved, sedentism introduced new health risks for human populations. Diseases associated with the transition to domestication and sedentary life may be divided into three main categories: dietary stress, biomechanical stress, and zoonotic disease.
This paper seeks to examine the skeletal pathologies and disease patterns resulting from the Neolithic transition as evidenced by archaeological remains recovered from prehistoric sites in Iran.
Skeletal Pathologies Related to Changes in Physical Activity in Neolithic Communities
With the onset of domestication, food production, and sedentary settlement, decreases in mobility and changes in subsistence practices introduced new stresses on the human body. Activities such as herding, cultivation, and animal husbandry placed new forms of strain on skeletal systems. Archaeological evidence of joint pathologies from Neolithic sites in Iran illustrates these consequences.
1. Osteoarthritis
Osteoarthritis is the most common form of degenerative joint disease, affecting not only humans but also birds, whales, dolphins, dogs, cats, and even dinosaurs dating back 200 million years. Evidence of degenerative joint changes, especially osteoarthritis, is also observed among hunter–gatherers. For instance, in prehistoric communities of the American Southwest, bilateral osteoarthritis of the elbows was particularly frequent among women, reflecting repetitive physical activities requiring bilateral arm use, such as grinding grain with quern stones.
At Hajji Firuz Tepe, osteoarthritis represents the most common pathology, affecting approximately 63% of adults. At Ganj Dareh, out of 34 individuals studied, nine (26.5%) exhibited vertebral osteoarthritis, including marginal lipping, eburnation, and horizontal osteophytes, all of which were restricted to adult individuals.
2. Ankylosing Spondylitis
Ankylosing spondylitis is a chronic inflammatory rheumatic disease primarily affecting the axial skeleton, characterized by back pain, stiffness, reduced mobility, and fatigue. In advanced cases, inflammation leads to ossification of the spinal ligaments and ankylosis of large joints. Onset usually occurs in the late second or early third decade of life. At Ganj Dareh, one elderly male exhibited ossification of the anterior longitudinal ligament and ankylosis involving at least four thoracic vertebrae, likely resulting from prolonged strenuous physical activity.
Diseases Associated with Nutritional Change in Neolithic Populations
1. Anemia
Anemia is the most widespread nutritional disorder worldwide, affecting particularly children and women of reproductive age. Neolithic farmers relied heavily on cereals, which are poor in iron and contain phytates that inhibit iron absorption. This led to iron-deficiency anemia, manifested in skeletal lesions such as porotic hyperostosis and cribra orbitalia. At Ganj Dareh, 85% of adults showed porotic hyperostosis, while 82.2% displayed ectocranial porosity on cranial vaults. Similar conditions have been documented at other Neolithic sites across Southwest Asia, including Zawi Chemi in Iraq, where 42% of skeletons displayed anemia-related lesions. At Hajji Firuz, cribra orbitalia was reported in one-third of the sample.
2. Dental Caries
A major health problem following the adoption of agriculture was dental decay, due to increased carbohydrate consumption. Teeth, being directly influenced by diet, provide excellent evidence for subsistence transitions. Caries occurs when oral bacteria ferment carbohydrates, producing organic acids that demineralize enamel and dentine. At Ganj Dareh, analysis of 366 juvenile and 228 adult teeth revealed no caries in individuals under 30 years of age. By contrast, the Hajji Firuz sample showed high frequencies of carious lesions. Comparative evidence from Çatalhöyük in Turkey also reveals significant caries prevalence, associated with cereal-based diets.
Diseases Linked to Population Growth and Animal Domestication
1. Epidemics and Infectious Disease
Population growth following the Neolithic transition increased risks of communicable diseases. Rathbun reported that approximately 30% of Neolithic skeletal samples from Iran and Iraq displayed signs of infection. While no skeletal evidence of tuberculosis was detected at Ganj Dareh (Merrett, 2004: 212), TB has been documented in the Zagros at Zawi Chemi. Similar findings at Çatalhöyük indicate periosteal infections but no evidence of mycobacterial disease.
2. Zoonotic Infections
Close human–animal interaction in early villages facilitated zoonotic transmission. Rabies was transmitted by dogs, while measles, diphtheria, and tuberculosis derived from cattle.
- Brucellosis (Malta Fever): Caused by Brucella bacteria, transmitted via direct contact, inhalation, or consumption of contaminated dairy and meat. Evidence from Ganj Dareh suggests early brucellosis: one elderly male exhibited lytic vertebral lesions diagnostic of infection.
- Plague: Caused by Yersinia pestis, plague is one of the oldest epidemic diseases, transmitted to humans via fleas from rodent reservoirs. Although no direct evidence of plague has been found in Neolithic Iran, it likely posed a significant risk to early farming communities.
Conclusion
This study has examined pathological conditions associated with plant and animal domestication in Neolithic Iran. Skeletal evidence from Hajji Firuz, Ganj Dareh, and other sites reveals a wide spectrum of health consequences. Sedentism and agriculture introduced repetitive physical strain leading to osteoarthritis and ankylosing spondylitis. Nutritional stress, particularly iron deficiency, caused widespread anemia manifesting as porotic hyperostosis and cribra orbitalia. The reliance on carbohydrate-rich cereals led to significant dental caries. Population growth, combined with the close cohabitation of humans and animals, facilitated the spread of infectious and zoonotic diseases such as brucellosis, while raising the potential for epidemics.
Although skeletal material from Neolithic Iran remains scarce and unevenly analyzed, available evidence highlights the crucial role of bioarchaeological research in reconstructing health and lifestyle in early farming societies. The Neolithic transition, while marking a turning point in human subsistence and social organization, also exposed populations to novel risks, many of which continue to challenge humankind today.