Men digging a ditch marked with string.

Data Science in Politics of Yellow Fever: Discovering the Cause of Yellow Fever

By Tannaz Motevalli, Sarah Eilers, Laura Hartman, and Erika Mills

In the previous blog post “Data Science in Politics of Yellow Fever: Medical Research Before ‘Data’,” we began to examine how researchers in the past used data to inform their search for the cause of yellow fever, and how the integration of data in medical research created compelling, yet not always accurate, results. In this second and final part of our series, we explore how data was used after the discovery that mosquitoes were transmitting the disease and the impact of this discovery on society at large.

A book cover
The Etiology of Yellow Fever: A Preliminary Note, Walter Reed, James Carroll, Aristides Agramonte, and Jesse W. Lazear, 1901.
National Library of Medicine #101209381

In 1881, it was Dr. Carlos J. Finlay who first proposed a link between mosquitoes and the transmissions of yellow fever. Two decades later, the U.S. Army Yellow Fever Commission, led by Dr. Walter Reed, conducted the research to confirm Finlay’s original hypothesis. The Commission presented their findings at the American Public Health Association’s 1900 annual meeting. In this joint publication of their findings presented at the annual meeting, the Commission offers facts and figures through charts, tables, and other diagrams to support their conclusions. The discussion is concise, focused on describing the data and explaining research methodology. The Etiology of Yellow Fever was meant to communicate scientific information to an audience of peers and medical professionals. After Walter Reed confirmed mosquitoes as the disease vector, the U.S. Army began a mosquito control campaign.

A page of book text
A Few General Directions with Regard to Destroying Mosquitoes, Particularly the Yellow-fever Mosquito, William Crawford Gorgas, 1904.
National Library of Medicine #101177822

William Gorgas, a physician and the chief sanitary officer of the Panama Canal Commission, oversaw the most successful anti-mosquito campaigns. In 1904, he issued guidelines for eradicating mosquitoes that included detailed descriptions of mosquito breeding and how the insects’ breeding impacted the transmission of yellow fever. Gorgas argued that by eliminating the presence of adult mosquitoes capable of spreading the disease, eradicating yellow fever could become a possibility. His guidelines advocated for major environmental and infrastructural changes including draining ponds and swamps, constructing public water systems; and the use of mosquito netting. Despite being published by the Government Printing Office, his guidelines emphasized the need to make this information accessible to all, even those outside the federal government, stating:   I thought an account of the relations of mosquitoes to disease, given in simple terms, readily understood by those who are not doctors, might help people generally in making an attempt to get rid of mosquitoes, each man about his own house.” 

Film and Video in the Politics of Yellow Fever

During the 1940s–1960s, mosquito control continued to take priority when protecting the public from yellow fever. Military initiatives for mosquito control began to introduce heavy use of insecticides claiming magnificent results. Audio-visual material in the NLM historical collections documents this shift towards using chemicals for mosquito eradication. Larvicides—chemical pesticides targeting mosquitoes in the larval form—as a “miracle treatment” is a common theme in films from this era. In DDT: Weapon Against Disease, the insecticide is sprayed in every space where soldiers live and work and is hailed as a lifesaver.

DDT: A Weapon Against Disease, 1945
National Library of Medicine #9502511

As part of the companion special display to Politics of Yellow Fever in Alexander Hamilton’s America, NLM curatorial staff selected eight films for presentation on a monitor in the History of Medicine Reading Room. These films represent more than 125 audio-visual titles in our holdings on the topic of yellow fever or malaria. The Library’s historical film collection is largely composed of educational and instructional films. A significant feature of this film genre is the processing and depiction of data into a form of information that intended viewers can best digest.

Hand Ditching for Malaria Control, 1949
National Library of Medicine #8800526A

This transformation of data into information presented as visual media rapidly increased, as the NLM resource Medicine on Screen explains in a section on public sector filmmaking. The people in the Office of Malaria Control in War Areas, which evolved into the CDC, knew that mosquitoes were the vector for malaria and other diseases, and they knew of effective ways to suppress that vector. To ensure implementation of these methods, they chose to show, not just tell, what needed to be done. They made films such as Hand-Ditching for Malaria Control, distributing and screening them to those who would direct and carry out the work.

Public health officials continued to produce instructional films to prepare staff to successfully implement mosquito control as in Policies and Procedures for Staff of the Aedes Aegypti Control Program (1946). These films often promoted the use of, and provided instructions for, how to use dangerous pesticides like DDT. To protect soldiers wherever they were stationed and the communities around them, the U.S. military encouraged the use of DDT to kill mosquitoes.

The American public also became a crucial audience for these films. The promotional and recruitment film, It’s Up to You: Dengue-Yellow Fever Control (1945) emphasized the American public’s obligation to do its part in protecting the community from the spread of yellow fever. In the film, the U.S. Public Health Service promotes its successful anti-mosquito campaign and asks community groups to volunteer in this effort. This call to action demonstrates how film can be a powerful messenger of complex information in a way that is accessible regardless of audiences’ education or literacy levels.

Data Reveals Even More

A group of white men in U.S. Army uniforms
How magic is DDT, James Stevens Simmons, 1945
National Library of Medicine #101705588

In 1945, Brigadier General James Stevens Simmons praised the effectiveness of DDT in an article titled, “How Magic is DDT” in the Saturday Evening Post. He downplayed negative concerns about its use by referencing how much research had been done in support of its effectiveness and safety. Notably, much of that research was conducted by the chemical industry at the request of the U.S. Army.

In 1962, ecologist Rachel Carson exposed the questionable integrity and bias in the chemical industry’s data. Her independent research provided incontrovertible proof that DDT was harming wildlife and increasing the incidence of cancer and other diseases in humans. The publication of her landmark book, Silent Spring, helped raise crucial concerns within the federal government regarding the disastrous consequences of overusing insecticides. A decade later the Environmental Protection Agency (EPA) was established and drafted its first act to ban DDT nationwide. In the 19th century, public health officials mistakenly believed that polluted air and soil were the causes of yellow fever. Ironically, the anti-mosquito campaigns of the 20th century created real hazardous health conditions in the air and soil.

Yellow fever and its threat to global health served, in many ways, as a catalyst for creating data through new forms of record-keeping. At a time when the concept of data science had not yet been fully articulated, the epidemic spurred the creation of data visualizations illustrating how the disease was spreading. And now, in the 21st century, new epidemics continue to prompt innovative uses of data to find sustainable and responsible ways of protecting communities. The history of yellow fever in the U.S. presents a fascinating case study of the evolution of knowledge, information, and data. More specifically, this case study shows us how throughout the history of medical research, people collected, shared, and analyzed data. This history serves as a lens through which we can think critically about data science today, as researchers from many different disciplines engage with it, and especially as it serves to advance the medical and public health enterprise.

Explore the online exhibition Politics of Yellow Fever in Alexander Hamilton’s America.

Tannaz Motevalli is a researcher and exhibition coordinator for the Exhibition Program in the History of Medicine Division at the National Library of Medicine.

Sarah Eilers is the Manager of Historical Audiovisuals in the History of Medicine Division at the National Library of Medicine.

Laura Hartman is Rare Book Cataloger in the History of Medicine Division at the National Library of Medicine.

Erika Mills is outreach coordinator for the Exhibition Program in the History of Medicine Division at the National Library of Medicine.


  1. The word “data” indicates plural numbers. Use datum for singular. This drives Biology professors nuts.

  2. Loved both parts. Can you do a Part 3 about how yellow fever, dengue et al are being controlled post Silent Spring and the dethroning of DDT as the miracle solution?

  3. Its indeed fascinating to see how in the past people uses the Data to work out there problems, and how it revolves around the years! Thanks for sharing Yah, Keep Sharing things I that 🙂

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