American Scientists Are Accused of Starting a Measles Epidemic in the Amazon Summary

  • Last updated on November 11, 2022

Patrick Tierney claimed that two renowned researchers, anthropologist Napoleon A. Chagnon and geneticist James V. Neel, started or exacerbated a measles epidemic among the indigenous Yanomami people of the Amazon in 1968. Conflicting accounts of what actually happened call into question some of Tierney’s accusations, which were made in his book Darkness in El Dorado (2000).

Summary of Event

Patrick Tierney claims in his book Darkness in El Dorado (2000) that American scientists Napoleon A. Chagnon and James V. Neel administered a measles vaccine to the Yanomami people of South America in 1968, leading to or exacerbating a measles outbreak among the population and causing thousands of deaths. Others believe, however, that the vaccine actually prevented the spread of measles. Confusion exists about whether such an outbreak of measles even occurred. Estimates of the dead range from zero to thousands. Questions also remain about whether measles had been present among the Yanomami prior to the vaccination efforts. [kw]Measles Epidemic in the Amazon, American Scientists Are Accused of Starting a (Sept., 2000) [kw]Amazon, American Scientists Are Accused of Starting a Measles Epidemic in the (Sept., 2000) Chagnon, Napoleon A. Neel, James V. Tierney, Patrick Venezuela measles epidemic Measles epidemic, Amazonian Amazon measles epidemic Chagnon, Napoleon A. Neel, James V. Tierney, Patrick Venezuela measles epidemic Measles epidemic, Amazonian Amazon measles epidemic [g]Central and South America;Sept., 2000: American Scientists Are Accused of Starting a Measles Epidemic in the Amazon[02990] [g]Venezuela;Sept., 2000: American Scientists Are Accused of Starting a Measles Epidemic in the Amazon[02990] [c]Publishing and journalism;Sept., 2000: American Scientists Are Accused of Starting a Measles Epidemic in the Amazon[02990] [c]Medicine and health care;Sept., 2000: American Scientists Are Accused of Starting a Measles Epidemic in the Amazon[02990] [c]Science and technology;Sept., 2000: American Scientists Are Accused of Starting a Measles Epidemic in the Amazon[02990]

The Yanomami, a remote tribe of indigenous, or Indian, peoples, inhabit areas of Brazil and Venezuela. They make up the largest indigenous group in South America, with an estimated population of twenty-two to twenty-seven thousand. They live in about three hundred villages that are spread out over a vast 70,000 square miles. The Yanomami are primarily hunters and farmers who live in relatively isolated areas and practice their traditional lifestyle. They comprise four Indian subdivisions, each with its own language: the Sanema of the northern sector, the Ninam of the southeastern sector, the Yanomam of the southeastern part of the Yanomami area, and the Yanomamo of the southwestern part of Yanomami area.

Chagnon and Neel spent many years working among the Yanomami. They filmed rituals and everyday life, collected genealogies, and took blood samples from the mid-1960’s until the late 1990’s. The government of Venezuela had banned (or revoked) Chagnon’s visa to travel to the lands of the Yanomami but Chagnon managed to travel into the country by listing himself as part of a group that was traveling under Neel.

The measles vaccine scandal was initiated when Tierney accused Chagnon and Neel of questionable ethical practices in administering to the Yanomami a dangerous measles vaccine that contained a live virus—the Edmonston B. Neel used the vaccine without the permission of Venezuelan medical authorities. Neel was interested in discovering how the previously unexposed Yanomami would react to the measles vaccine. Even though a better vaccine was available, the older version, Edmonston B, was used. Edmonston B was more onerous to administer, as it was necessary (as advised by the World Health Organization World Health Organization, the WHO, in 1965) to give a gamma globulin shot prior to the vaccine to help control side effects.

Tierney maintains that hundreds if not thousands of Yanomami died as a result of the use of the Edmonston B vaccine. A group of researchers from the University of Michigan and University of California, Santa Barbara, found that Edmonston B was safe and had been approved by the U.S. Food and Drug Administration and the WHO. Furthermore, this same research contends that the measles outbreak had already been in evidence for one year prior to the vaccine being administered. The former director of the U.S. Centers for Disease Control, William H. Foege, said that Edmonston B, while strong and sometimes causing severe reactions that mimicked a light case of measles, would not cause the large number of deaths claimed by Tierney.

Furthermore, Tierney claimed that Neel and Chagnon did not have proper consent to use the vaccine. However, researchers from Michigan and Santa Barbara argue that the Venezuelan medical officials had approved the use. Keith Wardlaw, a visiting Christian missionary present at the time in question, maintains that while Neel had nothing to do with the outbreak and was attempting to provide vaccines to the Yanomami to prevent the spread of measles, he nevertheless was refused permission to administer the vaccine by the Society for the Protection of Indians, a Venezuelan government agency. Furthermore, Wardlaw, who with his family had been with the Yanomami Indians during the measles outbreak, actually believed his young daughter had unknowingly introduced measles to the Yanomami.

In addition, evidence shows that the 1968 outbreak was not the first among the Yanomami. Thomas Headland, a noted anthropologist, asserted that at least four measles outbreaks occurred among the Yanomami prior to the time that Chagnon and Neel arrived in the area in 1968.

Another of Tierney’s assertions was that Neel did nothing to assist the Yanomami during the measles epidemic. Susan Lindee, a historian at the University of Pennsylvania who had access to Neel’s field notes, found that Neel provided Antibiotics antibiotics to the inhabitants of the Yanomami villages he visited. The researchers from Michigan and Santa Barbara also found that Neel provided medical assistance to the Yanomami and may have saved lives through his efforts. Wardlaw supports these claims.

The alleged misconduct reported by Tierney was first brought to light by two professors of anthropology in September, 2000. Terence Turner and Leslie Sponsel, after reading the manuscript of Tierney’s soon-to-be-published Darkness in El Dorado, sent an e-mail message to the American Anthropological Association American Anthropological Association (AAA) to warn the organization about possible repercussions if the allegations in the book indeed were true. They also urged the AAA to conduct a formal investigation into the work. Their e-mail was leaked to the press within days. In a subsequent letter, Turner and Sponsel stated that they had not taken a position on whether the book’s assertions about Neel or Chagnon were true or false. They claimed that the sole purpose of their original e-mail was to warn the AAA. Neither had done work on the Yanomami, nor had they ever written about Chagnon or Neel. Tierney, to his credit, had done field research with an indigenous population, the Kayapo of central Brazil, but not with the Yanomami. Furthermore, he has written about the ethics of working with indigenous populations.

In defense of Neel and Chagnon and countering the claims of Turner and Sponsel, the codeveloper of the Edmonston B vaccine, Samuel L. Katz, said that the same vaccine administered to the Yanomami was given to close to nineteen million children and infants around the world, including the United States, South America, Nigeria, and Burkina Faso, between 1963 and 1975 without major health problems. He insisted that the use of the Edmonston B vaccine could not have started or even exacerbated a measles epidemic.


Most of Tierney’s allegations, and certainly the allegation that Chagnon and Neel were responsible for a massive measles epidemic that caused thousands of deaths among the Yanomami, were refuted by various groups that included the AAA, by witnesses who were present at the time in question, and by other researchers. On November 13, 2000, the provost’s office at the University of Michigan, after spending hundreds of hours investigating the matter, issued a statement in support of Chagnon and Neel and against the claims made by Tierney in Darkness in El Dorado. Also, the office claimed that Turner and Sponsel had known about Tierney’s work on the book years before sending their e-mail message to the AAA. In turn, Sponsel and Turner denied the claims made by the provost’s office.

In February of 2001, the AAA convened a task force of professionals and academics who had direct knowledge of the activities in question. In its three-hundred-page report of May 18, 2002, the task force found that although Chagnon often was unethical in his research—including not obtaining proper consent from the government of Venezuela and the Yanomami for his studies—most of the allegations made against him and Neel by Tierney could not be corroborated. However, the report was rescinded by the AAA in June, 2005, for being unfair, flawed, and neglectful of Tierney’s rights to due process.

The Yanomami people have changed in many ways as a result of contact with the modern world. One Yanomami tradition that has not changed, however, is the belief that bodily matter should not be kept after an individual dies. Now advocating for their rights, the Yanomami, through their representatives, have requested the return of the blood samples taken by Chagnon and Neel. (The donors had not been told that their blood would be kept indefinitely.) While researchers have promised to return the samples (or destroy them—an alternate request), the Yanomami still wait and wonder. In the meantime, the scandal led to further academic debate on the ethics of research with indigenous peoples. Chagnon, Napoleon A. Neel, James V. Tierney, Patrick Venezuela measles epidemic Measles epidemic, Amazonian Amazon measles epidemic

Further Reading
  • citation-type="booksimple"

    xlink:type="simple">Borofsky, Robert, with Bruce Albert et al. Yanomami: The Fierce Controversy and What We Might Learn from It. Berkeley: University of California Press, 2004. This introductory work for students provides an overview of the Yanomani vaccine scandal and discusses the ethics of the case.
  • citation-type="booksimple"

    xlink:type="simple">Early, John D., and John F. Peters. The Xilixana Yanomami of the Amazon: History, Social Structure, and Population Dynamics. Gainesville: University Press of Florida, 2000. A study of the Yanomami before and after their contact with the modern world. Includes maps.
  • citation-type="booksimple"

    xlink:type="simple">Peters, John F. Life Among the Yanomami: The Story of Change Among the Xilixana on the Mucajai River in Brazil. Peterborough, Ont.: Broadview Press, 1998. A study of the effects of modern world contact on the Yanomami, based on the author’s experience of living with the Mucajai Yanomami of northern Brazil.
  • citation-type="booksimple"

    xlink:type="simple">Tierney, Patrick. Darkness in El Dorado: How Scientists and Journalists Devastated the Amazon. New ed. New York: Norton, 2001. The 2000 book that brought widespread attention to the research methods and ethics of Chagnon and Neel. This edition includes a new afterword.

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