The year 1992, which marked the quincentennial of Columbus's first voyage to the Americas, led to a flourishing of research on the biological and demographic impact of contact between two previously isolated and starkly different worlds. Numerous museum exhibits, academic conferences, and publications emerged from this period of reflection on the historic significance of 1492. Interest in the subject continues, as demonstrated by several new books on disease and the demographic impact of European contact on New World peoples.

In 1988, the Smithsonian Institution's National Museum of Natural History began developing a major Quincent-enary exhibit entitled Seeds of Change. The focus of this exhibit was not to be the history of Columbus and his voyages, but the biological impact of the collision of the Old and New Worlds that was set into motion by these journeys. The exhibit would highlight the exchange of plants, animals, people--and the diseases they carried with them--and how these exchanges dramatically transformed both worlds. I was completing a postdoctoral fellowship at the museum at the time and was drawn into the exhibit's planning through my own interests in the health and diseases of prehistoric peoples of the Americas. Herman Viola and Carolyn Margolis, the exhibit's codirectors, asked me to serve as curator for the disease section and as a consultant for the traveling and collaborative versions of the exhibit. They wanted me to examine the impact of European and, later, African diseases brought across the Atlantic by Columbus and his followers and the role they played in Europe's conquest and colonization of the Americas.

Researching the impact of Old World diseases raised some fundamental questions. How much do we know about health, disease, and mortality patterns in the Americas before European contact? How much can we reconstruct without a written history? What diseases plagued New World peoples? How were these diseases perceived, and how were they treated? How did medical knowledge and treatment in the Americas compare with that of 16th century Europe?

Such historians as Alfred Crosby (The Columbian Exchange: Biological and Cultural Consequences of 1492, 1972) and William McNeil (Plagues and Peoples, 1976) also had posed these questions, and many colleagues in anthropology and paleo-pathology had done research on the topic.

New World Medicinal Knowledge

Among the objectives of Columbus's voyages was to find medicinal plants to take back to Europe. Later explorers, conquerors, and colonists also expressed interest in New World medicines and medical treatments, although there are few written accounts for many parts of the Americas. Soldiers who accompanied Hernán Cortes in his conquest of Mexico are known to have been so impressed with the skill of Aztec physicians that they sought them out in preference to their own health practitioners. In fact, 16th century Europeans and New World peoples had similar approaches to the diagnosis and treatment of disease, and the materia médica on both sides of the Atlantic consisted largely of herbal preparations. There was little understanding of the causes of infectious diseases, nor were effective treatments available for the most deadly of them. In Europe, diseases commonly were attributed to imbalances in body humors, to "bad air," to astronomical alignments, or to the will of God. Similarly, New World healers, although keen observers of physical symptoms, attributed many diseases to supernatural causes. Nevertheless, practical knowledge of medicinal plants was well-developed in many New World cultures, as is documented in early historic sources.

Martín de la Cruz, an Aztec ticitl (physician) known only by his baptized name, and the Spanish friar Bernardino de Sahagún have left some detailed and fascinating glimpses of native American medical knowledge and medicinal plant use in central Mexico. Sahagún asked the sons of Aztec nobles to illustrate and record in writing their knowledge of medicinal plants and treatments for wounds and illnesses. De la Cruz described medicinal plants and their usage based on his firsthand experience as a physician. His Libellus de Medicinalibus Indorum Herbis (1552) and Sahagún's Florentine Codex (c. 1575-1580) contain a wealth of information--in painted illustrations as well as Nahuatl, Latin, and Spanish descriptions--of the state of medical knowledge in pre-contact Mexico. They include extensive lists of medicinal plants and instructions for their use in treating a wide range of ailments--including coughs, headaches, swellings, fever, intestinal infections, and traumatic injuries.

Unfortunately, there are no comparable works for South America, although a rich tradition of medicinal plant use and indigenous healing practices continues to this day among the kallawayas of Bolivia (see Perspectives in Health Volume 3, No. 1, 1998), the herbal healers in various Amazon rain forest cultures, and the curanderos of northern coastal Peru.

The bustling city of Chiclayo in northern Peru contains the largest market of medicinal preparations used in traditional healing to be found in South America. Here, a colorful panoply of flowers, fruits, plants, stalks, roots, seeds, bark, juices, and essential oils unfolds in row after row of neatly arranged wooden stalls. Venders know their merchandise well and are eager to navigate the prospective customer through a sometimes bewildering maze of tonics, tinctures, ointments, salves, and poultices, patiently explaining the healing properties of each. The abundance and variety of Chiclayo's offerings also have made it the market of choice for traditional healers who travel from a wide radius to acquire crystals, minerals, powders, staffs, swords, and other paraphernalia commonly used in healing procedures and ceremonies.

Several years ago, I spent a day wandering the aisles of Chiclayo with Don Víctor Bravo, a well-known and respected curandero from the nearby town of La Raya. I looked on as he purchased the materials he needed for a curing session and later watched as he assembled his mesa--an altar set on the dirt floor behind his house, where he practices his skills of divining and curing illnesses. Don Víctor learned these techniques from his uncle, who learned from his father, in a tradition passed down over generations. How far back this chain of knowledge extends is unknown, but its roots run deep on Peru's northern coast.

How effective are traditional healers such as Don Víctor at diagnosing and treating illness? Controlled studies are few, but judging from the number of patients who seek their help (often traveling from distant cities and even other countries), their services are clearly in demand. It should be noted that many of Don Víctor's patients seek help with problems more spiritual than organic, reflecting a common belief that physical ailments may be symptoms of psychological or spiritual imbalance. Don Víctor attempts to address both problems in his healing sessions.

The number of New World plants with demonstrated medicinal properties is growing as a result of various laboratory projects seeking new plant alkaloids with potential use in treating cancer, AIDS, and other diseases. These plants, many discovered through research with traditional healers in the Amazon rain forest, join others such as cinchona (the source of quinine) and coca, long recognized by Western medicine for their use in treating malaria and as an anesthetic.

Back to the Past

Although descriptions of New World medical practices from the early European contact period provide a window into the common health problems and treatments of that era, they reflect a very limited time depth. Questions about medical treatments and health conditions in prehistoric peoples of the Americas can be approached only through study of the archaeological record.

Paleopathology, the study of disease in ancient human populations, is a field that traces its roots to several academic disciplines, including anthropology, pathology, and the history of medicine. It has evolved from the occasional description of an unusual pathological specimen to a broader examination of disease from a population perspective. Researchers today increasingly are interested in broader questions, such as human adaptation to diverse environments, the health implications of major shifts in settlement pattern and diet, and the impact of European contact on native populations of the Americas.

Striking artistic depictions of people with deformities and pathological conditions were created by several New World cultures, most notably the Moche of northern Peru and the Nayarit and Colima of Mexico. These depictions provide a rare glimpse into the pre-Columbian world of disease and healing, although in most cases one only can hypothesize as to what disease is being depicted. More direct evidence of disease and common injuries is provided by human skeletal and mummified remains.

Pathological conditions commonly observed in skeletal remains include trauma, medical treatment, developmental and nutritional disorders, and various types of diseases--infectious, degenerative, neoplastic--that can affect bone. While injuries such as fractures and dislocations are relatively easy to identify, confident diagnosis of specific diseases can be more difficult. Many diseases do not affect the skeleton, and some affect bone in similar ways. Diseases detectable in skeletal remains typically are long-term ailments such as arthritis, chronic infections, and certain dietary deficiencies. Most illnesses that kill quickly, such as acute viral infections, do not leave their signature on the skeleton. Paleopathologists, therefore, are limited in the range of diseases they can detect in skeletal remains. Skeletal studies can be supplemented, however, by the examination of mummified bodies and coprolites (desiccated feces) found in dry climates, such as the southwestern United States, parts of Mexico, and the desert coasts of Peru and Chile. Over the past 20 years, studies of pre-Columbian mummified remains have documented not only the presence of chronic infectious diseases, such as tuberculosis and blastomycosis, but acute infectious diseases, such as bronchopneumonia and lobar pneumonia, as well.

In recent decades, new analytical tools have been developed for reconstructing ancient diet and in identifying the use of tobacco and medicinal plants such as coca. Elemental and stable isotope analyses of ancient human tissue have been used to reconstruct diet in various prehistoric population samples. The results of such studies have provided information on the relative importance of marine and terrestrial foods in the diet of coastal populations, documented the dietary adaptations of highland immigrants to coastal environments, and identified major dietary shifts, such as the adoption of maize agriculture. Such studies, in conjunction with the analysis of coprolites have made significant advances in reconstructing dietary patterns in the pre-Columbian Americas.

A recent breakthrough in the chemical analysis of human remains comes from studies of the hair of South American mummies. Chemical analyses adapted from forensic laboratories have been used to identify cocaine and cocaine metabolites in the hair of Chilean mummies dating to as early as 1000 B.C. The presence of cocaine and its metabolites in hair indicates early coca chewing, a tradition still widespread in the Andean highlands today, and is clearly shown in Moche ceramic sculptures. Nicotine and its metabolite cotinine also have been detected in some prehistoric hair samples from Chile and Peru, confirming archaeological and ethnohistoric evidence of tobacco use by native South American populations. Ongoing research suggests that it also may be possible to detect the use of hallucinogenic plant alkaloids such as tryptamines, as well, which would open further avenues for ethnobotanical research. These new laboratory techniques hold potential for substantially increasing our knowledge about plant use among prehistoric populations of the New World.

Evidence of Medical Treatment in the Pre-Columbian Americas

It is difficult to assess the medical knowledge and healing skills of pre-Columbian peoples of the Americas, given the lack of historic descriptions. However, there is evidence that basic skills, such as the splinting of broken bones and the cleaning and treatment of wounds, were well-advanced in native populations at the time of European contact. Well-aligned healed fractures in ancient skeletons suggest that successful manipulation and fixation of broken bones was an early-developed skill. More impressive, however, is evidence of two surgical procedures--amputation and trephination.

The Moche of northern Peru created modeled ceramic figures that appear to have had their feet amputated. For years, there has been debate about whether the Moche themselves performed amputations. What was lacking was convincing skeletal evidence to confirm the artistic depictions. Such evidence recently has been found at two north-coast Moche sites--footless skeletons showing healing and the type of bone reaction one would expect with amputation. These skeletons are important in confirming that Moche depictions of amputees were realistic portraits. Why the amputations were done, however, continues to be a subject for speculation.

Another surgical procedure practiced by some prehistoric populations of Mexico and Andean South America was trephination (also known as trepanation). Trephination is the removal of a portion of the skull vault by cutting, drilling, or scraping. It is one of the most dramatic examples of early surgery and has been found in a surprising number of prehistoric societies worldwide. In the New World, its distribution was limited to the region of Oaxaca in central Mexico and to the modern Andean countries of Peru and Bolivia.

The largest collections of prehistoric trephined skulls in the world come from Peru and Bolivia. There has been considerable speculation over the years about why these trephinations were done. Many Andean trephinations are associated with skull fractures, suggesting that the treatment of head injury and its complications may have been the principal motivation for the practice in prehistoric South America. Other motivations, such as the release of spirits or attempts to treat psychological disorders, are interesting speculations, but have not been demonstrated convincingly. What is most impressive is the percentage of trephinations that show healing, indicating a successful operation. Evidence of long-term healing, through extensive remodeling of the margins of trephinations, rises from about 33 percent in the earliest samples to a high of 71 percent in Inca samples--also an impressive record when compared with the poor survival rate associated with cranial surgery in Western medicine up until the 20th century.

Trephination is known to have been practiced in Peru and Bolivia for more than 2,000 years, from around 500 B.C. through the 16th century A.D. Curiously, although there is abundant archaeological evidence of Inca trephinations, there is no mention of the practice by Spanish chroniclers. The tradition may have been lost following the Spanish conquest, or perhaps it only went into hiding, as there have been sporadic reports of trephinations by traditional healers in Bolivia as recently as this century.

Ongoing Research and Future Directions

The study of historical documents, oral histories, and eyewitness accounts provides insight into the health status and medical practices of New World peoples at the time of early contact with Europe. Archaeological research and the study of human remains supplement this knowledge by providing a deeper understanding of the long-term adaptations of human populations in the New World. Modern advances in the techniques used to study skeletal and mummified remains continue to open new doors for researchers, and suggest new questions to ask about prehistoric lifestyle, diet, and medical practices.

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John W. Verano is Assistant Professor of Anthropology at Tulane University in New Orleans, Louisiana, and a Research Associate in the Department of Anthropology at the National Museum of Natural History in Washington, D.C. He is coeditor, with Douglas H. Ubelaker, of Disease and Demography in the Americas (Smithsonian Institution Press, 1992).