How Pests, Pathogens, and Pesticides Shape Geographies: A Story from the Early DDT Years in San Francisco Tlalnepantla

Picture of Dr. Wilbur A. Sawyer in his office, published in .

On Friday February 4, 1944, Pan American Airways flight 501 touched down in Mexico City an hour behind schedule. It was early afternoon when Dr. Wilbur A. Sawyer stepped off the plane and was greeted by colleagues from the Rockefeller Foundation’s International Health Division (IHD) and their Mexican counterparts. The arrival party whisked Sawyer from the airport through Mexico City’s historic district to Hotel Geneve, where George C. Payne and his wife had arranged a luncheon to celebrate Sawyer’s arrival.[1]

While he was unshaven and beleaguered, having left New York City the previous day and spent an overnight stopover in Brownsville, Texas, before continuing to Mexico City, 64-year-old Sawyer “made the best appearance [he] could,” striking up conversations with local Rockefeller Foundation staff.[2]

Over a selection of international fare, Sawyer spoke to Jacob George Harrar and Edwin Wellhausen about their experiments with maize under the Rockefeller Foundation’s Mexican Agricultural Program.[3] Then he chatted with Felipe Malo Juvera from the Mexican Ministry of Health and Welfare about the new health and training station he was organizing in Jalapa. As IHD Director, Sawyer had come to Mexico to monitor the Rockefeller Foundation’s work there, and conversations at the luncheon gave him a head start on his notes.[4]

When he turned in that night, Sawyer was exhausted. But there was no rest to be had over the weekend, not even on Saturday February 5, Mexico’s Constitution Day and a national holiday. Instead, as the streets outside buzzed with festivities, Sawyer visited the local offices of the IHD and the Rockefeller Foundation’s Natural Sciences Division as well as the U.S. Embassy.[5]

On Sunday before noon, he was off again, this time to the village of San Francisco Tlalnepantla, about 30 miles south of Mexico City.[6] Although Sawyer could not have known it then, of the vast number of projects in the Rockefeller Foundation portfolio at the time, the ongoing field experiment in San Francisco Tlalnepantla would have some of the most significant and far-reaching public health and environmental implications.

The experiment was a continuation of work begun by the ambitious William A. Davis the previous year. A Harvard alumnus like Sawyer, Davis had started at the Rockefeller Foundation’s Louse Lab when it was created in February 1942. Not an actual laboratory but rather an unofficial shorthand used to describe louse control research across the Rockefeller Foundation network, the Louse Lab took scientists like Davis to field research sites around the world in its two years of operations at the height of World War II.[7]

Controlling lice, fleas, and other pests was a preeminent concern in wartime, as they thrived in the cramped and squalid conditions that armed conflict fostered. The diseases they carried killed many more soldiers and civilians than figting ever did, and soldiers classed the six-legged evils and the aches and nausea they heralded as some of the worst horrors of warfare.[8]

The human body louse was a particular threat. The sesame seed-sized creature with translucent limbs and piercing-sucking mouthparts spread the itch and delirium of typhus, a disease that killed up to 40% of those infected when left untreated.[9] Alongside the Rockefeller Foundation’s Louse Lab, President Franklin D. Roosevelt created the United States of America Typhus Commission (USATC) by executive order in December 1942.[10] Both groups focused on developing efficient ways to prevent the spread of typhus during the war.

Fred Soper, a doctor on loan from the Rockefeller Foundation and a longtime colleague of Sawyer’s, was appointed to lead the USATC. Before turning his attention to louse-borne typhus, Soper had won recognition for his incredible success stamping out yellow fever- and malaria-carrying mosquitos in Brazil in the late 1930s.[11] After decades spent in South America, the USATC’s first assignment took Soper across the Atlantic to Egypt in January 1943.[12] While he oversaw fieldwork in Giza and Sharqia, Davis was busy experimenting on populations in villages across the Mexican Plateau.[13]

Under Soper and Davis, early louse control experiments were carried out using lousicidal powders containing Dow Chemical-supplied dinitrophenols, organic compounds also used to manufacture dyes and wood preservatives, or pyrethrins, chemicals derived from plants of the genus Chrysanthemum. A United States Department of Agriculture (USDA)-developed powder codenamed MYL, whose formula was withheld as a military secret, was also used in both Egypt and Mexico in 1943.[14]

But researchers at the field site in San Francisco Tlalnepantla in 1944 were testing a relatively new lousicide. A German chemist had only just discovered its insecticidal properties at the headquarters of chemical company Geigy half a world away in Basel, Switzerland. The substance had come to Mexico via the USDA, which had received samples from Geigy’s New York Office. After a few weeks of field testing with impressive results at its lab in Orlando, Florida, the USDA made quick plans to collaborate with the Rockefeller Foundation on further experiments and begin manufacturing the new louse killer: dichlorodiphenyltrichloroethane, or DDT for short.[15]

Sawyer and his colleagues arrived in San Francisco Tlalnepantla on horseback after having parked their car in Topilejo before continuing up rocky trails for about a mile and a half.[16] The village was home to 671 people, predominantly of Indigenous descent, who lived in what researchers labeled “generally poor” houses with “inadequate facilities for washing,” which favored “the maintenance of parasitization.”[17] The conditions comparable to what Sawyer had described in journals from his earlier trips to Rockefeller Foundation research sites in territories as diverse as India, Venezuela, and Brazil.

As IHD Field Director, Payne oversaw the on-site team of inspectors and nurses in San Francisco Tlalnepantla alongside a pair of colleagues from the Mexican Ministry of Health and Welfare: Malo Juvera and Carlos Ortiz Mariotte.[18] They began their work as the village was in the throes of a typhus outbreak, which had erupted a few months earlier and was at its peak when researchers first arrived in January 1944.[19] While Sawyer noted that their work had been “initiated to stop a sharp typhus epidemic,” it also provided ample opportunity for scientific inquiry.[20]

When researchers arrived in January, their first order of business had been transforming the remote village into a laboratory. They mapped the constellation of dwellings and took a careful census of the families who inhabited them.[21] The initial census allowed them to estimate that about ten percent of the population had fallen ill with typhus, and about ten percent of those who had fallen ill had succumbed to the disease.[22]

An absence of suitable housing for inspectors and nurses to stay overnight and the fact that many residents traveled far from the village for work complicated regular inspections.[23] To compensate, the research team adopted a flexible schedule, repeating house-to-house visits “as often as necessary” to perform delousing procedures and collect data.[24] As they began their inspections, researchers found that more than 80 percent of the village population was louse-infested.[25]

Over several weeks, delousing teams visited each home two or three times each at intervals of one week or more. Using a plastic tube perforated on one end and capped on the other for easy refilling, they sprinkled a 5%-DDT powder on the seams of residents’ clothes and then fluffed the garments to spread the powder.[26] They also treated residents’ scalps with a phenyl cellosolve-based lotion. “We saw three delousing teams at work in different parts of the village,” recalled Sawyer. “[They] seemed efficient and thorough.”[27]

Researchers explained to Sawyer that the typhus outbreak had ended after three weeks of delousing with only two cases of the disease reported in the third week. However, teams continued their work with the hope of ascertaining the longevity of their delousing procedures and the rate of return of the infestation.[28]

“The results were on the whole satisfactory,” wrote Sawyer.[29] He had long advocated for louse control as a means of fighting typhus, whereas others in the field put little stock in the idea and argued that attention should instead be focused on epidemiological studies and vaccine development.[30] But as work by the Mexico-based Rockefeller Foundation team in San Francisco Tlalnepantla and later in San Lorenzo Oyamel showed, DDT was a game-changer.[31]

Experiments in the latter half of 1943 in Algeria at Maison-Carrée Prison, the village of El-Arba, and a prisoner of war camp under Davis and Soper, who had established a Louse Lab-affiliated office at the Pasteur Institute of Algiers after breaking with the USATC that June, had also produced promising outcomes.[32] On Soper’s latest mission to arrest a burgeoning typhus epidemic in Naples, which had just gotten underway when Sawyer landed in Mexico, DDT would also prove itself — a combination of wartime need and impressive early results jumpstarting its eventual meteoric rise.[33]

The insecticide and its Swiss discoverer had a potent future on Mexican soil. The following year, it was used in some of the earliest residual spraying experiments on houses and outbuildings in a pair of towns in Morelos to test its efficacy against mosquitos.[34] In April 1946, local businessman Carlos Frohmader founded a new firm to produce DDT in Mexico.[35] Geigy held a controlling interest and continued to earn money from sales in Mexico as the use of DDT exploded into agricultural, municipal, and household use worldwide.[36]

But before its ascendance, subsequent acknowledgment of its little-studied harmful effects on ecologies and communities, and entrance into popular culture via the environmental movement of the 1960s and texts like Rachel Carson’s Silent Spring, DDT got its start in rural Mexico.[37] With experiments like the one Sawyer visited in San Francisco Tlalnepantla, local and foreign scientists and doctors and their new miracle insecticide assigned new meanings to populations and spaces through census-taking and mapping and redefined intercultural and interspecies relationships. 

For the visiting researchers and even more so for the scientists and administrators who would later read their reports, the census data and map of San Francisco Tlalnepantla constituted the village itself. Those representations and the decisions they influenced affected the lived experience of those in the village and countless others for whom the knowledge produced during that early experiment was (re)applied to shape their spaces.

These data and representations now find their way into the hands of historians who use them to produce knowledge about San Francisco Tlalnepantla’s past. One can only speculate about their impact on the local population at the time, how residents might have otherwise represented their home, and what alternative histories could be written from that knowledge.

Sawyer departed Mexico just after Valentine’s Day. It had been a whirlwind trip, and he was pleased with the work he had seen on all fronts.[38] Later that year, he left his position at the Rockefeller Foundation because the organization required all staff to retire at age 65.[39] But not yet ready to give up his career, Sawyer accepted the position of director at the United Nations Relief and Rehabilitation Administration (UNRRA) and continued to travel and work in public health and post-war cleanup and relief efforts for a further two years.

When the UNRRA was dissolved to make way for the newly formed World Health Organization (WHO) in 1947, Sawyer wrote an article reflecting on the organization’s achievements, including suppressing a series of what would have been devastating typhus epidemics during the war. In the article, he paid homage to the Rockefeller Foundation’s germinal field experiments in louse control. “Credit must be given,” he wrote, “to those who devised the practical and effective methods of delousing […] by powdering with DDT.”[40]

[1] Trip to Mexico and Western United States: 3–27 February 1944, Rockefeller Foundation Records, Officers’ Diaries, RG12 S-Z, Sawyer, Wilbur A. Rockefeller Archive Center, Sleepy Hollow, NY at 34.

[2] Ibid.

[3] On Harrar, see Rockefeller Archive Center, “J. George (Jacob George) Harrar” (n.d); On the Rockefeller Foundation’s Mexican Agriculture Program, see Barbara Shubinski’s “The Rockefeller Foundation’s Mexican Agriculture Program, 1943-1965.” Re:Source (January 4, 2022).

[4] Trip to Mexico, Rockefeller Foundation Records, 34; NLM, “Wilbur A. Sawyer;” For more on the Rockefeller Foundation’s work in Mexico, see Armando Solórzano Ramos, Fiebre dorada o fiebre amarilla?: la Fundación Rockefeller en México (1911-1924) (Guadalajara, Mexico: Universidad de Guadalajara, 1997); Marcos Cueto, Missionaries of Science: The Rockefeller Foundation and Latin America (Bloomington, IN: Indiana University Press, 1994); On the International Health Division, see John Farley, To Cast Out Disease: A History of the International Health Division of the Rockefeller Foundation (1913–1951) (Oxford: Oxford University Press, 2004).

[5] Trip to Mexico, Rockefeller Foundation Records at 35.

[6] Ibid.

[7] The Louse Lab was established in February 1942 and shuttered in March 1944, see e.g. Darwin H. Stapleton, “A Lost Chapter in the Early History of DDT: The Development of Anti-Typhus Technologies by the Rockefeller Foundation’s Louse Laboratory, 1942–1944,” Technology and Culture 46, no. 3 (2005): 513–540 at 518, 522.

[8] See e.g. comments from the from the Royal Army Medical Corps in Egypt during WWI, recorded in Serjeant-Major RAMC, With the RAMC in Egypt (London: Cassell and Company Ltd, 1918) at 168.

[9] Stapleton, “A Lost Chapter,” at 519.

[10] “Executive Order 9285 of December 24, 1942, Establishing the United States of America Typhus Commission,” Code of Federal Regulations, title 3 (1942).

[11] NLM, “Fred L. Soper: Fighting Yellow Fever and Malaria in Brazil, 1928-1942,” in Profiles in Science (n.d).

[12] Fred Soper, Building the Health Bridge: Selections from the Works of Fred L. Soper, ed. J. Austin Kerr (Bloomington, IN: Indiana University Press, 1970).

[13] Soper’s diaries contain notes on experiments in Met-Rehineh, Bidsa, and Ezbet Ramses, see Excerpt from Fred Soper’s diary, Egypt, Sections 1–3, 1943, The Fred L. Soper Papers, Box 6, NLM; Dusting Willagers with Louse Powder in Esbe Rameses, Egypt [Photograph], 1943, The Fred L. Soper Papers, Box 29, NLM; De-Lousing Clothing on a Street Corner in Mitrihena, Egypt [Photograph], 1943, The Fred L. Soper Papers, Box 29, NLM; On Davis’s early work in Mexico, see William A. Davis, Felipe Malo Juvera, and Pilar Hernandez Lira, “Studies on Louse Control in a Civilian Population,” American Journal of Epidemiology 39, no. 2 (March 1944): 117–88.

[14] Stapleton, “A Lost Chapter,” at 525–6, 532.

[15] Ibid., 528; For more on work at the Orlando, Florida laboratory, see Gordon M. Patterson, “Looking Backward, Looking Forward: The Long Torturous Struggle with Mosquitos,” Insects 7, no. 4 (2016): 56–70.

[16] Trip to Mexico, Rockefeller Foundation Records at 35.

[17] Carlos Ortiz-Mariotte, Felipe Malo-Juvera, and George C. Payne, “Control of Typhus Fever in Mexican Villages and Rural Populations Through the Use of DDT,” American Journal of Public Health 35 (Nov. 1945): 1191–1195 at 1192.

[18] Ortiz-Mariotte et al., “Control of Typhus.”

[19] Felipe Malo-Juvera and Carlos Ortiz-Mariotte, “Control de enfermedades transmitidas por piojos,” Boletín de la Oficina Sanitaria Panamericana 27, no. 12 (December 1948): 1113–24 at 1120; Ortiz-Mariotte et al., “Control of Typhus” at 1192.

[20] Trip to Mexico, Rockefeller Foundation Records at 35.

[21] Ortiz-Mariotte et al., “Control of Typhus,” at 1192.

[22] Trip to Mexico, Rockefeller Foundation Records at 35.

[23] Ibid.; Nurses were recruited either locally or from “among those having a similar cultural background to that of the population of the specific area where they were to work.” They were also selected based on age and ability to “cope with rural conditions,” see Carlos Ortiz-Mariotte, “Campaña Nacional contra el tifo en México,” Boletín de la Oficina Sanitaria Panamericana 34, no. 3 (March 1953): 236–44, at 244.

[24] Trip to Mexico, Rockefeller Foundation Records at 35; Ortiz-Mariotte et al., “Control of Typhus,” at 1192.

[25] Malo-Juvera and Ortiz-Mariotte, “Control de enfermedades transmitidas por piojos,” at 1120.

[26] Ortiz-Mariotte et al., “Control of Typhus,” at 1194; Malo-Juvera and Ortiz-Mariotte, “Control de enfermedades transmitidas por piojos,” at 1116; Trip to Mexico, Rockefeller Foundation Records at 34.

[27] Trip to Mexico, Rockefeller Foundation Records at 35; Ortiz-Mariotte et al., “Control of Typhus,” at 1192.

[28] Ortiz-Mariotte et al., “Control of Typhus,” at 1194.

[29] Trip to Mexico, Rockefeller Foundation Records at 35.

[30] Stapleton, “A Lost Chapter,” 527–8.

[31] Ortiz-Mariotte, et al., “Control of Typhus”; Malo-Juvera and Ortiz-Mariotte, “Control de enfermedades transmitidas por piojos.”

[32] Letter from Henry Stimson to Fred L. Soper, 31 May 1943, The Fred L. Soper Papers, Box 65, NLM. On Soper’s work at Maison-Carrée Prison near Algiers, see Report on Initial Work with Louse Powders at the Prison at Maison Carree, Algeria, Carried Out Under the Auspices of the Pasteur Institute of Algiers, July–August 1943, The Fred L. Soper Papers, Box 65, NLM; Report on the Work with Louse Powders at the Prison at Maison Carree, Algeria, after November 1943, The Fred L. Soper Papers, Box 65, NLM.

[33] Report on the Control of Typhus in Naples, Italy, December 9, 1943, to January 2, 1944, 21 January 1944, The Fred L. Soper Papers, Box 65, NLM; Charles M. Wheeler, “Control of Typhus in Italy 1943-1944 by Use of DDT,” American Journal of Public Health 35 (February 1946): 119–29; As John H. Perkins notes, the testing and application phases of DDT were unusually accelerated due to wartime needs, see “Reshaping Technology in Wartime: The Effect of Military Goals on Entomological Research and Insect-Control Practices,” Technology and Culture 19, no. 2 (April 1978): 169–86.

[34] Darwin H. Stapleton, “Lessons of History? Anti-Malaria Strategies of the International Health Board and the Rockefeller Foundation from the 1920s to the Era of DDT,” Public Health Chronicles 119 (March–April 2004): 206–215 at 210–212.

[35] Betrifft: Mexico-Productos DDT S.A., December 18, 1946, Geigy Produktion Agrochemie DDT Länder I–Z 1943–8, Box PA71A, Novartis Company Archive, Basel, CH.

[36] Geigy’s sales of pest control agrochemicals in Mexico in 1948, for example, were more than half a million Francs, see e.g. Aktennotiz über Besprechungen mit Herrn Dr. Georg Ragaz, c/o Productor DDT S.A., Mexico, December 16/19, 1947, Geigy Produktion Agrochemie DDT Länder I–Z 1943–8, Box PA71A, Novartis Company Archive, Basel, CH.

[37] Rachel Carson, Silent Spring (Boston, MA: Houghton Mifflin, 1962); On DDT’s story, see e.g. Elena Conis, How to Sell a Poison: The Rise, Fall, and Toxic Return of DDT (New York: Bold Type Books, 2022).

[38] Trip to Mexico, Rockefeller Foundation Records at 42.

[39] NLM, “Wilbur A. Sawyer: Post-War Work: UNRRA and Retirement, 1944-1951,” in Profiles in Science (n.d).

[40] Wilbur A. Sawyer, “Achievements of UNRRA as an International Health Organization,” American Journal of Public Health 37 (Jan. 1947): 41–56 at 46.

*Cover image description: Portrait of Wilbur A. Sawyer in his office, published at the National Library of Medicine.

[*Cover image description: a black and white portrait of a man sitting by his desk, looking at the camera. He is holding a pen with his right hand and there is a paper and flowers on his desk. He is in a small office, with a desk, a map and a door in the background.]

Edited by Lívia Regina Batista, reviewed by Asmae Ourkiya.

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