Suppression of Yellow Fever

Date June, 1900-1904

After it was confirmed that yellow fever is transmitted by mosquitoes, the U.S. government undertook a successful campaign to eradicate the disease in the United States and its dependencies by eliminating mosquitoes.

Locale Cuba; Panama

Key Figures

• Carlos Juan Finlay (1833-1915), physician and biologist
• William Crawford Gorgas (1854-1920), surgeon in the U.S. Army Medical Corps
• Walter Reed (1851-1902), head of the Yellow Fever Commission

Summary of Event

Throughout the eighteenth and nineteenth centuries, yellow fever, which originated in tropical America, had devastated the Atlantic and Gulf coasts of the United States. During an epidemic in 1878, more than four thousand people died of yellow fever in New Orleans alone. In 1898, after Spain lost the Spanish-American War and withdrew from Cuba , the United States adopted the objective of eradicating yellow fever from that Caribbean island. Because physicians in the United States suspected that the fever was caused by unsanitary conditions in Cuba, initial efforts consisted of large-scale cleanup operations.

The cleanup task was assigned to Major William Crawford Gorgas, a surgeon attached to the U.S. Army of Occupation. Conditions in Cuba, especially in Havana, the country’s largest city, had worsened as a result of the insurrection and the war against the Spaniards. Convinced that unsanitary conditions were responsible for the prevalence of yellow fever, Gorgas set about his work with remarkable energy. In 1899, he claimed that Havana was probably the cleanest city in the world. The hypothesis that cleanliness would eliminate yellow fever seemed briefly confirmed: During the first six months of that year, only seven deaths in Havana were attributed to yellow fever.

In August, 1899, new Spanish immigrants began arriving in Cuba in great numbers, and yellow fever again appeared in an epidemic of catastrophic proportions. It became apparent that the low incidence of the disease in the preceding months had not been due to the sanitary conditions introduced by Gorgas but to the scarcity of people who had not developed an immunity to the disease.

In June, 1900, the surgeon general of the United States, George M. Sternberg, appointed a Yellow Fever Commission consisting of four medical doctors: Walter Reed, a major in the U.S. Army Medical Corps and head of the commission; James Carroll and Jesse W. Lazear of the United States; and Aristides Agramonte of Cuba. After the commission arrived in Cuba, its members met with Carlos Juan Finlay, a Cuban physician and biologist serving with Major Gorgas on a special commission to diagnose suspected cases of yellow fever. To Finlay, there was no question about the mechanism of contagion of yellow fever. In 1881, he had announced to a medical congress in Washington, D.C., his conviction that the disease was transmitted by a mosquito then called Stegomyia calopus, which was later called Stegomyia fasciata and is now known as Aedes aegypti.

Finlay’s announcement had been received with skepticism. The concept of insects serving as carriers, or vectors, of human diseases was not widely understood, and Finlay had not shown consistent development of yellow fever in volunteers who had been bitten by mosquitoes that had previously bitten victims of yellow fever. Despite years of experimentation, his strongest arguments remained the correlation of yellow fever cases with the geographical areas in which the mosquito thrived, and certain characteristics of the disease that suggested transmission by injection.

Reed soon became acquainted with Henry Rose Carter, another physician who was studying how yellow fever was spread. In 1898, while he was an inspector for the Public Health Service, Carter had investigated a yellow fever epidemic in Taylor and Orwood, Mississippi. There he observed that people who visited homes of people stricken with yellow fever during the first ten to twelve days of their illnesses seldom contracted the disease, but a large percentage of visitors who visited the homes after that period—even if the patients had died and been removed—were stricken.

Carter presented his findings to Reed, who reasoned that this suggested that an insect carried the disease. Health professionals were just becoming aware of Theobald Smith’s discoveries concerning ticks spreading Texas fever and of investigators who had proved that malaria was transmitted by a mosquito species. This gave a new legitimacy to the concept of insect transmission of yellow fever, and the commission decided to undertake a serious investigation of Finlay’s theory.

Stegomyia mosquitoes provided by Finlay were used in the experiments. The mosquitoes were first fed on patients infected with yellow fever and then fed on healthy volunteers taken from among U.S. soldiers and Spanish immigrants. Careful records were kept of the progress of the disease in the patients and volunteers. After many failures and Lazear’s own death from the disease, the researchers discovered that the disease was infectious only during the first three days of illness. Armed with this information and the knowledge that ten to twelve days must elapse before the disease could be contracted by a second person, the researchers were able to produce yellow fever in nonimmune subjects at will.

After it was established that the disease was transmitted by the Stegomyia mosquito, the work of eradicating the plague reverted to Gorgas, who eventually decided to do away with the mosquito itself. Gorgas operated under the authority of the U.S. army and had the cooperation of the mayor of Havana, who declared it a crime for residents to allow mosquitoes to breed on their property. The main effort was a vigorous sanitary campaign engineered and supervised by Gorgas.

With military precision and scientific thoroughness, Gorgas devised a plan of attack based on the habits of the Stegomyia mosquito: destruction of its breeding grounds, which usually involved house-to-house searches for stagnant water and the imposition of fines on houses in which mosquito larvae were found; fumigations; division of Havana into districts under Sanitary Department representatives; and quarantines imposed on the houses of people affected by yellow fever. Crews spread oil on standing water and cisterns to kill mosquito larvae, inspected land, ordered standing water drained, stocked ponds with fish that ate mosquito larvae, and educated the public about the health hazards. Other teams followed up on yellow fever victims, sealing their rooms with paper strips, burning pyrethrum powder insecticide to kill mosquitoes, and attracting mosquitoes to lights to be killed directly. Neighbors within range of mosquitoes were watched for symptoms of yellow fever. These techniques were effective, and by the end of 1901, yellow fever ceased to be a serious problem in Cuba.

Gorgas’s experience in Havana caused many public health officials in the United States to consider mosquito control not only for the control of yellow fever in the far South, but also for the control of malaria, another mosquito-borne disease. New Orleans, which had almost always faced yellow fever threats, was the first city to seize upon mosquito-control measures to curb the disease.

In 1904, Gorgas was ordered to Panama after the United States had acquired the rights to build a canal through the isthmus, which officials of the French Panama Company had called “the white man’s graveyard” when they had tried to build a canal earlier. Yellow fever, as much as corruption among the officials of the French-financed project, thwarted the efforts of the company to build the canal.

In Panama, Gorgas had to battle not only the dreaded mosquito but also the opposition of the authorities in charge of the canal project. It took all Gorgas’s persuasive abilities and the specter of an epidemic of catastrophic proportions to convince the canal builders that the eradication of yellow fever depended on the destruction of the Stegomyia mosquito. In 1914, the Panama Canal was opened for the first time to commercial transportation. This amazing engineering accomplishment was largely the result of Gorgas’s perseverance and insistence on sanitary conditions.

Significance

The U.S. policy of establishing public health services and sanitary conditions in occupied countries continued. During the second U.S. occupation of the Dominican Republic , from 1916 to 1922, sanitary regulations were strictly enforced. During the occupation of Haiti in 1915, one of the first measures of the military government was to divide the country into sanitary districts, each in the charge of a public health officer. Such measures instituted in Veracruz in 1914 led to a sharp drop in the mortality rate of the Mexican population, and occupying forces remained free of tropical diseases and pestilences peculiar to the area.

These policies benefited all concerned. Effective pest control and hygienic procedures provided people with far healthier living conditions and enabled other countries to engage in commercial and military relations within the sanitized areas without risking their own citizens’ lives.

Bibliography

Dormandy, Thomas. Moments of Truth: Four Creators of Modern Medicine. Hoboken, N.J.: John Wiley & Sons, 2003. Study of four major contributors to modern medical advances, including Walter Reed, who is the subject of six chapters.

Ellis, John H. Yellow Fever and Public Health in the New South. Lexington: University Press of Kentucky, 1992. Vividly describes the impact of yellow fever in the epidemic of 1878, including the formation of sanitary associations in New Orleans and other major southern cities.

Finlay, Carlos E. Carlos Finlay and Yellow Fever. New York: Oxford University Press, 1940. Interesting account of Finlay’s life and the development of his theory on the causes and prevention of yellow fever, from records translated by his son. The son’s interpretations and the father’s papers are interwoven in a harmonizing but distinguishable fashion.

Gibson, John M. Physician to the World. Durham, N.C.: Duke University Press, 1950. Useful biography of Major William Crawford Gorgas.

Greene, Emily, ed. Occupied Haiti. New York: Writers Publishing, 1927. Critical report of the U.S. occupation of Haiti, pointing out that the only aspect of the occupation that the Haitians did not resent was the accomplishment of the Service d’Hygiene.

Humphreys, Margaret. Yellow Fever and the South. New Brunswick, N.J.: Rutgers University Press, 1992. This careful explanation of the history of yellow fever includes original data on the extent of early epidemics, the succession of discoveries, and the campaign waged following the fuller understanding of insect transmission after 1900.

Pierce, John R., and Jim Writer. Yellow Jack: How Yellow Fever Ravaged America and Walter Reed Discovered Its Deadly Secrets. Hoboken, N.J.: John Wiley & Sons, 2005. Lively history of the impact of yellow fever on the United States and Walter Reed’s contributions toward its eradication.

Truby, Albert E. Memoir of Walter Reed: The Yellow Fever Episode. New York: Paul B. Hoeber, 1943. Study of the methods that Reed and his colleagues used to show how mosquitoes carried yellow fever.

Yellow Fever Studies. Public Health in America. New York: Arno Press, 1977. A collection of critical papers reflecting the major breakthroughs in yellow fever control.