Gorgas Develops Effective Methods of Mosquito Control Summary

  • Last updated on November 10, 2022

Employing recent discoveries on the role of mosquitoes in the transmission of malaria and yellow fever, William Crawford Gorgas applied strict sanitary controls within the Panama region, enabling construction of the Panama Canal.

Summary of Event

With the discovery of gold in California in 1848, considerable interest quickly developed in the United States concerning the construction of a transoceanic canal through Central America that would shorten the distance and thus the time then necessary to travel from the East Coast to the West Coast. Flush with his success in building the Suez Canal during the 1860’s, Ferdinand de Lesseps Lesseps, Ferdinand de of France initiated efforts in the 1870’s to construct such a canal by organizing the necessary financial backing and arranging for preliminary surveys. After evaluating a number of potential routes, Lesseps and the leaders of his Panama Canal Company decided on a sea-level canal cutting through the narrow Panamanian isthmus between Colón and Panama City. They initially envisioned that the proposed canal would be 9 meters (29.5 feet) deep and 30 meters (98.4 feet) wide, and that it would cost a total of 658 million francs to build. Mosquitoes as disease vectors Yellow fever Panama Canal;yellow fever Diseases;yellow fever [kw]Gorgas Develops Effective Methods of Mosquito Control (1904-1905) [kw]Mosquito Control, Gorgas Develops Effective Methods of (1904-1905) Mosquitoes as disease vectors Yellow fever Panama Canal;yellow fever Diseases;yellow fever [g]Latin America;1904-1905: Gorgas Develops Effective Methods of Mosquito Control[00930] [g]Panama;1904-1905: Gorgas Develops Effective Methods of Mosquito Control[00930] [c]Health and medicine;1904-1905: Gorgas Develops Effective Methods of Mosquito Control[00930] Gorgas, William Crawford Ross, Ronald Reed, Walter Stevens, John Frank Finlay, Carlos Juan

The highly skilled French engineers faced formidable challenges when they arrived in Panama at the start of the project, in 1881. These challenges included taming the unpredictable Chagres River as well as overcoming obstacles to excavation at Culebra, where geological formations resulted in a continual problem with landslides. The most difficult and, indeed, insurmountable obstacle confronting French engineers and workers during the 1880’s, however, was the high incidence of various diseases, especially malaria Malaria and yellow fever. In 1889, a virtual epidemic on several occasions decimated the workforce and ultimately ended Lesseps’s venture. After eight years in Panama, the French had lost an estimated two thousand workers to yellow fever and more than fifty-five hundred to other illnesses. A second brief attempt to continue excavation ensued during the 1890’s, but in the end Lesseps and the French failed. The episode was tragic testimony to a misguided, optimistic faith in science and technology that was incommensurate with the realities of the project.

Despite the failure of the French, American interest in building a canal intensified after the Spanish-American War. Beginning in 1904, the United States embarked on a canal construction program that succeeded where the French had not. The reason for this achievement can be traced to advances in tropical medicine related to the eradication of malaria and yellow fever.

Throughout the nineteenth century, most physicians thought that diseases were spread by odors; Panama, with its abundance of decomposing vegetation and animal carcasses, possessed conditions that supported this idea. This so-called miasma theory of disease Miasma theory of disease was gradually refuted. In the case of malaria, it was disproved by the English physician Sir Ronald Ross, who worked in isolated Secunderabad, India. During the late 1890’s, Ross showed that the Anopheles mosquito spread the disease after it had fed on an infected patient, and he carefully investigated the malaria parasite, Plasmodium falciparum, in the mosquito’s stomach and salivary glands. It became obvious to Ross that in order to stamp out malaria, one had to isolate the mosquito from those infected, and he systematically outlined his sanitary ideas in his Mosquito Brigades and How to Organise Them, Mosquito Brigades and How to Organise Them (Ross) published in 1901.

Concurrent with the publication of Ross’s book, a team of U.S. Army doctors, which included Walter Reed and William Crawford Gorgas, were eliminating yellow fever in Havana, Cuba, using similar public health techniques. Reed, building on the work of Cuban physician Carlos Juan Finlay, who first suggested that the mosquito was the carrier of yellow fever, had concluded that only one type of mosquito, Stegomyia fasciata, was responsible for the dreaded “yellow jack.” Once Reed and his colleagues had determined the particular pattern of incubation, it was clear that to eliminate yellow fever, one had to prevent the propagation of the insect by keeping the female Stegomyia fasciata from laying its eggs.

Gorgas employed this theoretical understanding of yellow fever in his practical public health efforts in Havana. He learned that water had typically been left standing inside the sickrooms of French engineers and workers at the Panama Canal Company’s hospital at Ancón, Panama, during the 1880’s, and, tragically, the water had served as a mosquito breeding ground. He ordered such water immediately disposed of or sealed off with wooden lids or screens. Further, following a suggestion made by entomologist Leland O. Howard, Gorgas directed that any water left standing was to be covered with a thin film of kerosene or oil whenever this method was feasible. In addition, adult mosquitoes were killed by the fumigation of every house in Havana where a case of yellow fever had appeared. The doors and windows of the houses were tightly sealed, and sulfur or powdered pyrethrum was burned in pots designed specifically for that purpose.

William Crawford Gorgas.

(U.S. Army)

Reed’s discoveries and Gorgas’s sanitation campaign in Cuba were great achievements of the day, and the results were dramatic. Because the insect had only a ten-day life cycle, the Stegomyia population diminished rapidly. With this significant accomplishment, the stage was set for Gorgas’s work in Panama beginning in 1904. As a deeply religious man, Gorgas had long thought of his life experiences as ordered and ordained by God for the purpose of readying him for this one great task.

Somewhat ironically, although Gorgas’s success in Cuba was derived from Reed’s scientific work, Gorgas had been extremely resistant to the idea that yellow fever was transmitted by mosquitoes. Born in Mobile, Alabama, in 1854, he received his undergraduate education at the University of the South, located in Sewanee, Tennessee, and his medical degree at New York City’s Bellevue Hospital Medical College. Interested in medicine more as a means to enter the army than as a profession, Gorgas joined the U.S. Army Medical Corps in 1880. He initially served at a number of outposts in the West, but with the onset of the Spanish-American War, he was sent to Cuba on the Santiago expedition, and later to Havana, where he was first placed in charge of yellow fever patients before his appointment as chief sanitation officer.

In 1904, Gorgas was sent to Panama as the Isthmanian Canal Commission’s chief sanitary officer, charged with the elimination of two major obstacles to the completion of the American project there: malaria and yellow fever. However, despite the work of Ross and efforts in Cuba, most of the political leadership in Washington and key members of the commission, including Admiral John G. Walker and Governor George W. Davis, did not believe in the mosquito transmission theory. Gorgas’s arguments fell on deaf ears until a deadly epidemic hit the Canal Zone in the spring and early summer of 1905 and John Frank Stevens was subsequently appointed the commission’s chief engineer.

Stevens, an engineer with considerable railroad experience, recognized that if the canal project were to succeed it had to be designed using locks and gates rather than constructed at sea level. Most significant, the excavation of the so-called Culebra Cut hinged on the removal of dirt using an extensive rail network. Above all, Stevens clearly perceived that before construction could begin effectively, diseases such as yellow fever and malaria had to be eliminated; he knew that Gorgas needed to receive unequivocal support in addressing this task. Thus, in 1905, Stevens’s engineering department stood behind Gorgas, who now had first priority in terms of men and materials.

By the fall of 1905, Gorgas had more than four thousand men engaged in sanitation work, and his budget was increased dramatically. Supplies necessary for the eradication of mosquitoes were ordered and received in unprecedented quantities, including 120 tons of pyrethrum powder, 300 tons of sulfur, and 50,000 gallons of kerosene per month. Fumigation pots, screens, buckets, garbage cans, and brushes were soon in abundance; this equipment was used in the subsequent house-by-house campaign. As a result of these efforts, cases of yellow fever in the Canal Zone fell from sixty-two in June, 1905, to twenty-seven in August and one in December, with no further outbreaks in 1906. By using similar techniques to combat the Anopheles mosquito, Gorgas’s team was able to reduce malaria, but that disease was not totally eradicated because the Anopheles mosquito had a much broader range of flight and bred in a more widespread area than did the mosquito that transmitted yellow fever.


Gorgas’s measures to control the spread of mosquito-transmitted diseases in Panama had both short- and long-term significance. Although malaria proved to be much more difficult to contain than yellow fever, construction on the Panama Canal progressed steadily to its completion and the opening of the waterway to commercial traffic on January 1, 1915. For his pioneering efforts, Gorgas received numerous honors, including honorary degrees from the University of the South, the University of Alabama, Harvard University, and The Johns Hopkins University. In 1907, he was appointed to the Isthmanian Canal Commission by President Theodore Roosevelt, and the following year he was elected president of the American Medical Association. Promoted to the rank of brigadier general and named surgeon general of the U.S. Army in 1914, Gorgas played an influential role in sanitation work during World War I. When he retired from the army in 1918, he became the director of the yellow fever program for the International Health Board of the Rockefeller Foundation and traveled to Central America and Peru during the last two years of his life. He implemented preventive procedures in other areas that were often subject to periodic outbreaks of yellow fever.

Gorgas’s methods were quickly implemented throughout South America and Africa. Considering the deadly nature of yellow fever, or vomito negro, an illness that typically claimed the lives of more than 50 percent of those afflicted, it was remarkable that between 1910 and 1925 no major epidemic occurred in temperate regions or in the traditional endemic regions located in Ecuador, Mexico, and Brazil. Furthermore, Gorgas’s practical sanitation techniques were subsequently complemented by scientific advances related to yellow fever. In 1918, researchers identified the microbe that caused the disease, Leptospira icteroides, a minute spiral organism that was studied extensively during the 1920’s.

Perhaps the most enduring legacy of Gorgas’s work is the Panama Canal itself, an undertaking that could not have been completed without his sanitation measures. During the first ten years of the canal’s operation, between 1915 and 1925, commercial transits increased from 1,072 to 4,673, and tolls rose from $4.3 million to $21.6 million. Because of the canal, shippers saved almost 12,900 kilometers (8,016 miles) sailing from New York to San Francisco, and almost 11,300 kilometers (7,021 miles) from New York to Honolulu. Use of the canal increased steadily before 1939, and in the post-World War II era traffic and tolls escalated dramatically, along with global trade and a dynamic international economy. Mosquitoes as disease vectors Yellow fever Panama Canal;yellow fever Diseases;yellow fever

Further Reading
  • citation-type="booksimple"

    xlink:type="simple">Bishop, Joseph Bucklin. The Panama Gateway. New York: Charles Scribner’s Sons, 1913. Written by the secretary of the U.S. Panama Canal Commission, this authoritative and comprehensive work covers the history of the region and canal construction efforts from the Spanish colonial era to the completion of construction. Chapters describing Gorgas’s sanitation efforts and the technology employed in the canal’s design are extremely detailed.
  • citation-type="booksimple"

    xlink:type="simple">Gorgas, Marie D., and Burton J. Hendrick. William Crawford Gorgas: His Life and Work. 1924. Reprint. Whitefish, Mont.: Kessinger, 2004. Although this hagiographic account must be read critically, it is an important source on Gorgas’s life. Sensitively cowritten by Gorgas’s widow, it includes many intimate family details and provides interesting perspectives on Cuba, Panama, and Gorgas’s work. Includes many anecdotes about historical figures as well as excerpts of several revealing letters.
  • citation-type="booksimple"

    xlink:type="simple">Gorgas, William Crawford. Sanitation in Panama. New York: D. Appleton, 1913. A definitive work describing the efforts of Gorgas and his sanitation department in Panama, this book is particularly valuable for its description of the campaign in Havana and the published correspondence between Walter Reed and William Gorgas. Many chapters include details concerning practical methods, hospital facilities, and quarantine procedures.
  • citation-type="booksimple"

    xlink:type="simple">Jasper, William F. “Taming Mankind’s Ancient Foes.” New American 21 (September 5, 2005): 37-40. Relates the story of Gorgas’s work in Panama, including his struggle to overcome bureaucratic opposition when he sought to employ the methods he had used successfully in Cuba to eradicate yellow fever.
  • citation-type="booksimple"

    xlink:type="simple">Krieg, Joann. Epidemics in the Modern World. New York: Twayne, 1992. An overview of the epidemiology of diseases. Discusses the effects of yellow fever epidemics on societies, politics, literature, and cultures.
  • citation-type="booksimple"

    xlink:type="simple">McCullough, David. The Path Between the Seas: The Creation of the Panama Canal, 1870-1940. New York: Simon & Schuster, 1977. One of the best historical works on the construction of the Panama Canal. Brilliantly portrays the main figures involved in the canal’s construction, including Gorgas, and perceptively explores broader historical themes related to the most massive engineering undertaking of the early twentieth century.
  • citation-type="booksimple"

    xlink:type="simple">Ross, Ronald. Memoirs, with a Full Account of the Great Malaria Problem and Its Solution. London: John Murray, 1923. A fascinating autobiography reflective of the role of public health efforts during the Age of Imperialism. Contains many letters and personal insights; a valuable source for anyone desiring to understand both Ross’s scientific achievement and the late Victorian society in which he lived.
  • citation-type="booksimple"

    xlink:type="simple">_______. Mosquito Brigades and How to Organise Them. New York: Longmans, Green, 1901. Written by the physician who won a Nobel Prize for his efforts in determining the role of mosquitoes in the transmission of malaria, this classic in the history of tropical medicine includes discussion of methods used to identify mosquitoes and organizational techniques aimed at waging a public health campaign to eradicate them. Concludes with a history of nineteenth century attempts to combat the disease and case studies of malaria control programs in different parts of the world.
  • citation-type="booksimple"

    xlink:type="simple">Wain, Harry. A History of Preventive Medicine. Springfield, Ill.: Charles C Thomas, 1970. Brief history of epidemiology and the spread of disease. One section is devoted to yellow fever in the Americas. Not particularly detailed, but provides a succinct overview.
  • citation-type="booksimple"

    xlink:type="simple">Williams, Greer. The Plague Killers. New York: Charles Scribner’s Sons, 1969. Excellent popular account of the campaigns against malaria and yellow fever. Focuses on the situation in mid-twentieth century Africa and includes useful description of epidemiological methods.

Reed Reports That Mosquitoes Transmit Yellow Fever

Panama Declares Independence from Colombia

U.S. Acquisition of the Panama Canal Zone

Construction Begins on the Panama Canal

Panama Canal Opens

Categories: History