International Sanitary Conferences

The Government of the French Republic initiated and hosted the first of 14 International Sanitary Conferences in 1851 to standardize international quarantine regulations against the spread of cholera, plague, and yellow fever. During the 19th century, however, lengthy debates focused mainly on cholera. Among the topics discussed were microbial versus miasmatic causes of cholera and the relative merits of hygiene, sanitation, and quarantine to control or prevent cholera’s spread, especially among European nations.

International Sanitary Conference. Report to the International Sanitary Conference of a commission from that body, to which were referred the questions relative to the origin, endemicity, transmissibility and propagation of Asiatic cholera. Boston [Mass. : s.n.], 1867. Page: (seq. 1). From the Center for the History of Medicine in the Francis A. Countway Library of Medicine.

Harvard’s Contagion collection brings together for the first time digitized copies of the proceedings in the public domain (as of 2008, when this exhibit was created): the first 11 International Sanitary Conferences, between 1851 and 1903.

Delegates at each of the first two conferences failed to agree on quarantine regulations against the international spread of cholera, and this trend continued for the next 40 years. For most of the 19th century, conference delegates were divided on both the cause and the mode of transmission of cholera. British delegates, in particular, staunchly opposed both the microbial explanation of cholera and the various quarantine measures that were proposed to control its spread.

In 1855, Max von Pettenkofer first proposed his localist/contagionist conviction that cholera was an airborne disease caused by a combination of three factors: a germ; the local and seasonal conditions that could activate the pathogen into cholera’s infective agent; and the predisposition of a person to infection. Concurrently, in the early 1850s, John Snow linked cholera in Central London’s Soho neighborhood to contaminated drinking water. Since Snow did not identify a pathogen that caused cholera, many conference participants remained convinced that cholera was an airborne disease.

These conferences were as unproductive as the first two in producing international agreement on preventing the spread of cholera. At the third conference, Pettenkoffer, modifying his earlier suggestion, proposed that cholera spread through air after a specific germ in the excrement of cholera patients reacted with “excrementitious matter” in moist soil and liberated an “active principle” into the air. The implications of Filippo Pacini’s isolation of Vibrio cholerae in 1854 that identified this bacterium as the cause of cholera, well before Robert Koch identified it in 1883, as well as Pacini’s published conclusion that a pathogen caused fatal diarrhea and dehydration in cholera victims, were not discussed.

For most delegates at the fourth conference (1874), the cause of cholera remained an enigma. For example, prominent figures of the age such as Rudolph Virchow, August Hirsch, and Adrien Proust only partially endorsed Pettenkoffer’s view that cholera was an airborne disease.

The United States convened the fifth conference (1881) to persuade other nations that every ship leaving its home port and traveling to the United States needed to carry a certified bill of health, but this motion failed. In other proceedings, Pacini and Pettenkoffer continued to disagree on the cause of cholera, and Carlos Finlay first proposed that an intermediate agent spreads yellow fever among people.

Pacini died two years before the sixth conference opened in 1895, and his observations and conclusions quickly fell into oblivion. Pettenkoffer now disputed Robert Koch’s conclusion that a comma bacillus was the sole cause of cholera. Koch also drew little support from medical researchers, scientists, and administrators because they believed that direct contact with the dejecta from cholera patients caused the disease to spread.

Delegates unanimously approved an international treaty for the first time in 41 years to establish maritime quarantine regulations for ships traveling from east to west via the newly built Suez Canal.

Delegates agreed to abandon land quarantine measures against cholera because serious cholera outbreaks had subsided in Europe. Pettenkoffer reported that swallowing a concoction of cholera vibrios, bacteria that cause cholera in humans, proved harmless to him and argued against Koch’s conviction that a specific germ, the comma bacillus, was the sole cause of cholera. Other proceedings focused on preventive measures that every country should enforce during an outbreak of cholera in a neighboring state.

At the ninth conference (1894), delegates successfully confronted the need to impose sanitary precautions at ports of departure to avert future cholera outbreaks among pilgrims traveling to Mecca. In other debates, contagionists, who believed that microbes caused infectious disease, tenaciously stood by their convictions that Koch’s bacillus was the cause of cholera. In opposition, anti-contagionists believed in a miasmatic cause of this disease, namely air contaminated by particles of decomposed matter (miasmata). Opinions on cholera in the 1890s were still as divided as they had been at mid-century.

Without precedence, discussions on plague dominated the tenth (1897) and eleventh conferences (1903), and participants agreed to reduce its spread by eliminating rat infestation. Delegates also agreed to consolidate and revise quarantine measures approved at preceding conferences, and, for the first time after half a century of debates, conference participants agreed that cholera was a waterborne disease.

The International Sanitary Conferences provided a forum for medical administrators and researchers to discuss not only cholera but also other communicable diseases. Ultimately, this spirit of international cooperation inaugurated in 1948 the World Health Organization, an agency of the United Nations, to direct and coordinate intergovernmental health activities. In 1965, the Judicial Commission of the International Commission on Bacteriological Nomenclature, responsible for the naming of bacteria and archaea, formally acknowledged Pacini’s pioneering bacteriological observations of the cholera pathogen and renamed it “Vibrio cholerae Pacini 1854.”

This is a partial list of digitized materials available in Contagion: Historical Views of Diseases and Epidemics. To search or browse all items digitized for the Contagion exhibit, please use the search bar in the top navigation menu or the "Limit Your Search" options in the left navigation menu (accessible from the exhibit's home page).

The following sources were used in writing this page.