The advent of modern public health

During the second half of the nineteenth century, the importance of hygienic measures was increasingly emphasised. At the time, ‘miasma theories’ assumed that fermentation, putrefaction and disease were closely related.

dirty water through sewers, paving and hygiene in general. The authors of these textbooks stated that ships needed to be scrupulously clean, while soldiers should exercise regularly during the journey and after arrival. Settlements in the colonies were built according to the latest hygienic ideas, which emphasised cleanliness, the free circulation of air, clean water and frequent bathing. Ideally, they were placed far away from swamps and places where organic matter decayed, as physicians at that time were convinced that the air carrying the smell of decay also carried the agents that caused malaria. Houses were to be placed far apart, and a cordon sanitaire between the European and native quarters needed to be maintained. Settlers in India often visited the hill stations, where it was much cooler, during the dry season.¹³ Settlers in Vietnam visited spas for the same reason.¹⁴

Most of all, physicians were convinced that Europeans should spend limited time in the tropics, alternate residence in the hot urban centres with stays in cooler areas in the mountains and enjoy frequent sabbaticals to their native country.

Despite the widespread pessimism about the possibility of European settlement in the tropics, a small number of health measures proved to be effective. In 1796, Edward Jenner developed a vaccine for smallpox after observing that milkmaids rarely suffered from the disease. He assumed that they had contracted cowpox instead, which provided them with immunity against smallpox. Jenner’s method consisted of inoculating humans with cowpox. It was also possible to vaccinate individuals with material derived from the cowpox pus­tules of previously inoculated individuals. As had been noted earlier, smallpox had ravaged indigenous populations in the Americas and Asia. As early as 1803, the king of Spain ordered the crew of the Balmis Expedition (named after the personal physician to the Spanish king, who led the mission) to bring the vaccine from Spain to the Caribbean, South America, the Philippines, Macau and China. The ship had twenty-two orphans on board who were the living carriers of the vaccine—the first two orphans were vaccinated just before departure; two more were vaccinated with the pustules of the first two, and so on.¹⁵ In the 1810s, smallpox vaccination campaigns were organised in the Dutch East Indies, and were followed by campaigns in British India a decade later.

During the last quarter of the nineteenth century, Western nations competed with each other to acquire the few remaining areas in the world that were not yet under their con­trol. At the same time, they initiated scientific missions to explore the territories already acquired. Until 1850, when colonialism focussed mostly on trade, it was only necessary to acquire and maintain small settlements near ports. After 1850, colonial empires shifted their attention to develop the territories they had acquired for economic gain through the establishment of plantations for sugar, coffee, tea, rubber, tobacco, indigo and other cash crops, as well as through the extraction of natural resources such as tin, copper and oil. This new emphasis in running the colonies required significant increases in the size of Western populations, the education of indigenous individuals to become lower-rank office workers, and the mobilisation and at times migration of large groups of indigenous unskilled labourers. Indian coolies working on plantations in Guyana, South America, struggled to acclimatise there, as did the Javanese in Surinam. As a consequence of these changes in the nature of colonialism, the global circulation of individuals and goods increased exponentially and, with it, the risk of an increased and global circulation of disease pathogens. Although Western nations continued to take measures for the protection of the health of European settlements and military personnel (quinine was massively distributed among soldiers to prevent ‘intermittent fever’, later recognised as malaria, from the 1850s on), they also had to develop an interest in the health of the indigenous workforce. Maintaining indigenous manpower for the plantations had become essential for the success of the colonial enterprise in the course of the nineteenth century.

The risk several contagious diseases posed had become all too familiar around the world at the time. No fewer than five pandemics of ‘Asiatic cholera’ hit the temperate world between 1817 and 1896. Singapore, the main transportation hub in South-east Asia and a key platform for workforce distribution within the British Asian Empire, experienced several outbreaks of typhoid in the 1880s. The bubonic plague, which originated in Yunnan, China, is considered to have killed almost thirteen million people in colonial empires in the 1890s. States took extensive precautionary measures against the spread of contagious disease by imposing quarantine measures, restricting trade and limiting travel during epidemics, generally with mixed results. The demands of trade required the free circulation of goods and people while maintaining health required restrictions in these movements. For this reason, quarantine measures were often contested. In addition, it became clear that preventing the spread of disease required new forms of international cooperation.

Between 1851 and 1892, seven international sanitary conferences were held to discuss possible measures to contain the global spread of epidemics. Initially, the participants of these conferences focussed on limiting the diffusion of cholera; subsequently, plague and yellow fever dominated the discussions. As early as 1865, the Sanitary Council of Alexandria was responsible for the declaration of quarantines around the Suez Canal, which had become an essential transit point connecting three continents, and the construction of a huge lazaretto there. The Pan-American Sanitary Bureau (soon to be renamed the Pan-American Health Organization) was founded in 1902, followed by a series of organisations based in Europe including the Office International d’Hygiene Publique (founded in Paris in 1907), which collected and disseminated statistics on the incidence and prevalence of infectious diseases in participating nations (eventually, it was able to provide information from sixty different countries). The League of Nations Health Organisation’s Oriental Bureau, established in Singapore in 1926, initiated a number of missions that led to the development and implementation of preventive and treatment approaches appropriate to the specific conditions in several locations in Asia. It conducted, for example, influential field studies on malaria in the 1930s, paving the way for the Global Malaria Eradication campaign of the World Health Organization (WHO) in the 1950s.¹⁷