Wataru Iijima. Disease, Colonialism, and the State: Malaria in Modern East Asian History. Hong Kong University Press, 2009.

This chapter examines the process of malaria eradication in Yaeyama of the Ryukyu Islands in the twentieth century. The Ryukyu Islands are divided into four local districts, Amami, Okinawa, Miyako, and Yaeyama. The history of the islands is very complicated; they were not part of Japan proper before the mid-nineteenth century. The Ryukyu Kingdom was established in the fifteenth century and sent tribute to the Chinese Ming and Qing dynasties. The center of the Kingdom was Naha in Okinawa, while Amami, Miyako, and Yaeyama were under the rule of Okinawa. In 1609, the Shimazu lord of Satsuma of Tokugawa Japan invaded the Kingdom, and Amami was put under the direct rule of Satsuma. After that, the Ryukyu Kingdom, Okinawa, Miyako, and Yaeyama came under the control of Satsuma and Tokugawa Japan, but continued to send tribute to China. After the Meiji Restoration in 1868, the Japanese government abolished the Ryukyu Kingdom, annexing it in 1879, and ruling it as Okinawa prefecture. In 1945, toward the end of World War II, the U.S. military attacked and landed on Okinawa, taking over control of the Ryukyu Islands until their return to Japan in 1972.

This complicated history influenced the process of malaria eradication in Yaeyama. There were two types of malaria in the Ryukyu Islands. In general, malaria in Amami and Okinawa, the northern parts of the islands, were the relatively mild Plasmodium vivax and P.malariae. In Miyako and Yaeyama, in addition to the non-malignant types, there was the severe P.falciparum, which was also found in Taiwan and other tropical regions. In the history of Yaeyama and Miyako, malaria greatly influenced social, economic, and political developments until its eradication in the 1960s.

Non-malignant malaria had a long history in Japan and the Ryukyu Islands. On the other hand, legend has it that falciparum became prevalent only in the early sixteenth century after a Dutch commercial ship from Southeast Asia drifted to Iriomote in the Yaeyama Islands. Actually, further investigation is needed to determine its origin in Yaeyama and Miyako, although historical documents indicate a post-sixteenth century beginning. In the first half of the eighteenth century, Sai On, the Prime Minister of the Ryukyu Kingdom, forced many people to relocate to the Yaeyama Islands, including Ishigaki and Iriomote, to develop rice production. The new area, however, was malarious and many succumbed to the disease. There was a close relationship between the movements of people and malaria transmission in Yaeyama, and environmental changes resulting from migration for rice production was an underlying factor in the prevalence of the disease.

After the annexation of the Ryukyu Islands by the Japanese Meiji Government, the new migration policy for agricultural development, including the production of sugar cane, also aggravated the malaria problem which finally led to the termination of the migration policy. After the Meiji period, many companies, including Mitsui, likewise found it difficult to develop coal mining at Iriomote because of the prevalence of malaria. Indeed, a central theme in the history of Yaeyama was the battle between the Yaeyama people and malaria.

The purpose of this chapter is to discuss the importance of colonial Taiwan’s model of malaria control in Japanese colonial medicine and examine the process of malaria eradication in Yaeyama in the twentieth century. The historical significance of Yaeyama’s case in the context of the history of malaria in East Asia and the world will be evaluated. Yaeyama’s experience is important because it reflected changes in approaches to malaria eradication in the twentieth century: from a model developed in Taiwan under Japanese colonial rule to a U.S. model supported by the World Health Organization (WHO). This chapter also highlights the contributions made by Japanese researchers and research institutes to the development of colonial medicine and their role in anti-malaria efforts in Yaeyama, Taiwan and other Japanese colonial possessions. The process of malaria eradication in Yaeyama in the twentieth century can be divided into three stages: the implementation of the Taiwan model from 1920 to 1945; a transitional period from 1945 to 1957; and the introduction of the Wheeler plan and the use of dichloro-diphenyltrichloroethane (DDT) residual spraying under the U.S. model from 1957 to 1968.

The main feature of the Taiwan model was the administration of quinine to malaria patients and blood tests for all residents in malaria eradication districts. The U.S. model, on the other hand, relied on DDT residual spraying. In other words, the Taiwan model targeted the parasite, while the U.S. model targeted the anopheles mosquito. The conflict between the anti-parasite and anti-anopheles approaches provided the dynamics of the development of the malaria eradication program in Yaeyama, and the history of the process also reflected the change of the political balance of power in East Asia in the twentieth century.

There is a huge amount of material available for studying malaria eradication in Yaeyama. Primary sources include the pre-1945 documents of the Malaria Eradication Team and Malaria Eradication Office under the Okinawa prefecture, and those of the Ryukyu government under U.S. military rule after 1945—both of which are now available at the Okinawa Prefecture Archive (OPA). From these records, we can obtain a detailed picture of the malaria eradication process in Yaeyama in the twentieth century.

Malaria Research and Research Centers

Since the chapters by Ku and Liu in this volume have discussed in detail the anti-malaria program in colonial Taiwan, I shall focus on the role played by scholars from two research institutes in Japan in the establishment of colonial medicine and the advancement of malaria research in the colony. The methods of malaria control that emerged would provide the model for anti-malaria efforts in Okinawa. The establishment of Japanese colonial medicine in Taiwan in the late nineteenth century was closely related to the development of malaria studies in Taiwan and infectious disease research in Tokyo. The centers of colonial medicine research of the Japanese Empire were Densenbyo Kenkyujyo (Institute for Infectious Disease), and Kitasato Institute. During the last decade of the nineteenth century, the Japanese government planned to establish a central institute to study infectious diseases, which were the main causes of mortality at that time. Kitasato Shibasaburo was the most important scholar in the establishment of Japanese infectious disease studies. He graduated from Tokyo Imperial University in 1883 and had studied in Germany under Robert Koch. Later, he joined the Public Health Bureau under the Ministry of Home Affairs where he had a close relationship with Goto Shinpei, chief of the Public Health Bureau. Conflict, however, developed between Kitasato and scholars of the Medical School of Tokyo Imperial University over the establishment of the central institute for infectious disease studies. Kitasato had in mind a central institute modeled after Koch’s German Central Institute for Infectious Diseases and established a research center, the Densenbyo Kenkyujyo, or the Institute for Infectious Disease in 1892, with the support of the Public Health Association of Japan and some health leaders, including the chief of the Public Health Bureau. Scholars influenced by Kitasato were active in the research and control of infectious diseases in Japan proper, as well as in other East Asian countries, with the support of Goto Shinpei. Most well-known was their work in Hong Kong in the 1894 bubonic plague pandemic. In 1899, the Institute for Infectious Disease was placed under the control of the Public Health Bureau, and became the National Institute for Infectious Disease, one of the centers for the study of infectious and parasitic diseases and a vaccine mass-production facility.

Many scholars conducting research in infectious and parasitic diseases had been influenced by Kitasato. A member of Kitasato’s inner circle was Takagi Tomoe, the first chief of the vaccine production facility of the National Institute. He played a major role in researching bubonic plague in Hong Kong with Kitasato, and also made an important contribution in establishing quarantine measures against Asiatic cholera and other infectious diseases for military forces returning from the Sino-Japanese War in 1895. In 1900, Takagi became the chief of the Quarantine Section of the Public Health Bureau, and his close relationships with Kitasato and Goto Shinpei played a role in his being appointed head of the Public Health Bureau of the Japanese colonial government in Taiwan two years later. He also became the president of the Medical College of the Japanese Colonial Government in Taiwan established in 1899. Takagi contributed greatly to the establishment of public health in colonial Taiwan and was nicknamed “Eisek Sotoku” (Governor of Public Health).

In 1914, the National Institute for Infectious Disease was transferred from the Public Health Bureau to the control of the Ministry of Education and the Medical School of Tokyo Imperial University. Kitasato, who was not consulted about the change, and many of his associates retired from the National Institute at this time and established the Kitasato Institute. Kitajima Taichi, chief of the Quarantine Department of the Public Health Bureau and an important member of Kitasato’s inner circle, granted the Kitasato Institute the license to manufacture many kinds of vaccine. The revenue helped fund research activities of the Kitasato Institute, and members of the Institute went on to establish the Medical School of Keio University in 1916, with Kitasato as its first dean. There was rivalry and conflict between the Kitasato Institute and the Medical School of Keio University on the one hand, and scholars of the Institute for Infectious Disease of Tokyo Imperial University on the other, but scholars influenced by both institutes played important roles in the establishment of colonial medicine in Taiwan.

Colonial Medicine and the Taiwan Model

The history of medicine and public health in colonial Taiwan was mainly one of attempts to control infectious diseases, especially bubonic plague and malaria. After the outbreak of bubonic plague in Hong Kong in 1894, the disease spread to many coastal cities in East Asia, including those in Taiwan. The first public health measures introduced in colonial Taiwan were designed to control plague through the establishment of maritime quarantine and a public health system in urban districts. After plague came under control, the colonial government began a malaria eradication program in 1911. The Research Committee on Local and Infectious Diseases in Taiwan, established in 1899, was the center of malaria study in the colony, and scholars from the Institute for Infectious Disease and the Kitasato Institute were vital to the advancement of malaria research there. For instance, Miyajima Mikinosuke, who spoke at the annual meeting of the Research Committee on Local and Infectious Disease in Taiwan in 1903, was one of the key figures in the establishment of public health in Japan and had conducted research on malaria in the Kyoto area. After leaving the Institute for Infectious Disease, he joined the Kitasato Institute in 1914 and continued his malaria studies. Prominent health leaders like Takagi Tomoe, chief of the Public Health Bureau and later president of the Medical College of the Japanese Colonial Government in Taiwan, were knowledgeable about different approaches to malaria control, including the British model which targeted the anopheles mosquito, the German approach which targeted the parasites, and the Italian approach which called for housing reforms. In fact, Takagi emphasized the importance of combining the three approaches. The Medical College of the Japanese Colonial Government was one of the centers for infectious disease studies, including malaria, in Taiwan, and Kinoshita Kashichiro, a malariologist of the College, was a leader of the anti-malaria program before 1910.

In 1916, the colonial government established the Department of Hygiene of the Central Institute which played a major role, with scholars of the Medical College of the Japanese Colonial Government, in the development of tropical medicine in Taiwan. Many of its researchers came from the Institute for Infectious Disease and the Kitasato Institute. One of these scientists, Koizumi Makoto, who was greatly influenced by Kitasato Shibasaburo and Takagi Tomoe, emerged as a top malaria researcher in colonial Taiwan. Koizumi also conducted research in Malaya, Manchuria, and Yaeyama in the Okinawa Islands. Significantly, his study and experience led him to emphasize the importance of the anti-anopheles method of malaria control. After he returned to Tokyo and became professor of the Medical School of Keio University in 1924, his research was continued by others, including Morishita Kaoru, researcher of the Kitasato Institute, who also favored the anti-anopheles approach.

The history of the anti-malaria program in colonial Taiwan was one of conflict between the anti-parasite method using quinine and the anti-anopheles method involving vector destruction and environmental reforms. Despite studies by malariologists such as Koizumi and Morishita which suggested that the anti-anopheles approach would be more effective, the Japanese colonial government in Taiwan selected the anti-parasite method because of budget constraints. After the 1910s, the colonial government established malaria eradication districts, and began administering blood tests and quinine to all residents in those districts. Such tests were enforced by a regulation enacted in 1913, and those failing to comply would be punished. The gradual expansion of the anti-malaria program played an important colonizing role in rural districts, including those of the aborigines. As Ku and Liu have shown, the Japanese colonial government did not succeed in eradicating malaria, but Japanese scholars gained much experience from their efforts in Taiwan, and helped to establish Japanese tropical medicine. I shall call these methods and the social system in which such methods were implemented the “Taiwan model.”

With the development of Japanese colonial medicine based on the experience gained in colonial Taiwan, the Japanese government applied medical and public health policies to other colonies: Korea, Guandong Leased Territories in Manchuria, Nanyo Leased Territories of Micronesia, and Manchu-kuo. The Japanese colonial government used medicine and public health as a tool of colonization in those regions, and many scholars sent from the Institute for Infectious Disease, Kitasato Institute and Keio University played important roles in those regions. Their contribution to tropical medicine, especially their research and control of tropical diseases including malaria, was hailed by Kato Takaaki, the Prime Minister of Japan, in a speech in 1925 at the Tokyo Conference of the Far Eastern Association for Tropical Medicine. He stated:

The success of the Suez Canal and the development of the tropic regions were due to the development of tropical medicine. The Japanese government established tropical medicine in Taiwan and the Nanyo Islands. As a result, Japanese scholars will play an important role in the field of tropical medicine.

Malaria Eradication in Yaeyama: The Taiwan Model, 1920-1945

In the late nineteenth century, with the Japanese government supporting malaria eradication in Yaeyama, many Japanese scholars conducted malaria research in the islands which had gained strategic importance with the change of international situation around the time of the Sino-Japanese War. The Japanese government made much of the position of Yaeyama as the southern border. By the turn of the century, the Japanese government began to deliver quinine to several districts in Ishigaki, the center of the Yaeyame Islands, but the program was terminated in 1913 because of fiscal difficulties. Local Yaeyama leaders, however, formed a committee to push for the continuation of eradication efforts. Ganeko Rakuichio, an Okinawa native who had conducted research on malaria in Yaeyama in 1892 and 1894 and had also consulted with Takagi Tomoe in Taiwan about malaria eradication, tried to impress upon members of the Japanese Diet in March 1919 the need for a malaria eradication program in Yaeyama. He suggested that the anti-parasite method was more suitable owing to financial constraints. The central government and Okinawa prefecture government subsequently decided to begin an anti-malaria program in Yaeyama.

It is noteworthy that the model to be adopted in Yaeyama was the Taiwan model. In 1919, Hatori Jyuro, the malaria eradication officer for the Japanese colonial government in Taiwan, conducted an investigation in Yaeyama and recommended the use of the anti-parasite method as developed in Taiwan. Another study in 1920, however, faulted the termination of the earlier program in 1913 and the absence of medical staff in the rural districts. Finally in September 1921, the government enacted the regulation for malaria eradication, and the Mararia Yobo Han (Malaria Eradication Team) was established a few months later. The team requested technical support from the Taiwan colonial government and a medical officer in the malaria eradication program became the team’s advisor. He supported the approach used in Taiwan, adopting its principles and method, and employing program advisors in Yaeyama who all came from Taiwan. The main method the team used was the administration of blood tests to all people and quinine to malaria patients. Anyone failing to participate in the program was punished by the police based on the regulation for malaria control passed in 1926, a revised version of the 1921 regulation. The team continued its efforts until 1930 when the agency’s name was changed to Mararia Boatsujo (Malaria Eradication Office).

The anti-parasite approach continued in Yaeyama until 1945. There was however, an attempt to use the minnows to reduce the number of mosquitoes. The use of the minnows actually began in 1919, and they were also employed in colonial Taiwan. Beginning in 1924, the fish were released into rivers, waterways, and rice fields and the Malaria Eradication Office kept track of the number of anopheles mosquitoes in the districts where minnows had been released. Thus, the minnow experiment revealed that some anti-anopheles measures were needed and these were adopted despite fiscal difficulties. But the anti-parasite method based on the Taiwan model remained the primary course of action adopted by the Malaria Eradication Office. Owing to these efforts, the prevalence of malaria in Yaeyama was limited to the rural districts, and there were no cases in the urban districts of Ishigaki. The Malaria Eradication Office, however, could not control malaria in the rural districts using just the anti-parasite method.

In 1945, U.S. military forces landed on the Okinawa islands, and Yaeyama was also attacked by the Royal Air Force. Japanese troops in Yaeyama ordered all civilians to move to the jungle, but many of those districts were malarious. As a result, many civilians, including primary school students, died from malaria—a tragic event remembered as the War Malaria Incident. In 1945, malaria morbidity reached 16,884 and 3,647 died from the disease.

Transition to the U.S. Model, 1945 to 1957

What is significant in these developments is that the inadequacy of the Taiwan model had already been revealed during the Pacific War. After full-scale war broke out in China in the summer of 1937, Japanese forces operating in southern China faced the serious problems of epidemics of malaria and other infectious diseases. Many Japanese scholars who worked in the colonies, especially malariologists in Taiwan, were mobilized by the Japanese Army and Navy. In an attempt to protect Japanese soldiers, Shimojyo Kumaichi, chief of the Public Health Bureau of the Japanese colonial government in Taiwan, was sent to Guangdong province, China, to study the prevalence of infectious diseases including malaria, and the Taiwan model of relying on blood tests and administering quinine was used in Japanese occupied areas in Guangdong. Other scholars also carried out research in East Asia and Southeast Asia. A major concern for the Japanese government was the potential for an outbreak of a malaria pandemic in Japan proper when soldiers infected with malaria on the battlefields returned home.

After 1941, Japan went to war against the U.S., Britain, and the Netherlands in Southeast Asia and New Guinea. Military operations in the Pacific involved attempts to control malaria and other infectious diseases, and the Japanese Army and Navy adopted the anti-parasite method based on their experience in colonial Taiwan. Japanese military leaders believed that the use of quinine would be sufficient to control malaria before the commencement of military operations. The malaria problem was very serious during the war and military operations in Micronesia, New Guinea, the Philippines, and Burma were affected by malaria and other infectious diseases. Yet the anti-parasite model proved inadequate especially when there was a shortage of quinine, and the Japanese army decided to switch to the anti-anopheles approach on the battlefields in Burma and New Guinea. At the same time, the Japanese Army and Navy mobilized young students from Medical Schools of Imperial Universities and Medical Colleges to serve as military doctors and these students organized many research programs during the war. Two of them emerged as prominent scientists in the postwar period. Sasa Manabu graduated from the Medical College of Tokyo Imperial University and was on the research staff of the Navy Medical College. He conducted research in many types of anopheles mosquito in Southeast Asia and New Guinea. Otsuru Masamitsu graduated from the Medical School of Taihoku Imperial University and joined the Army. He researched malaria in Guangzhou, Guangdong Province. Based on their respective work and experience, Sasa and Otsuru became leading scholars in the field of infectious and parasite studies after World War II.

In the meantime, U.S. military forces had organized the South Pacific Malaria and Insect Control Organization and began to rely on DDT to kill anopheles mosquitoes. Not surprisingly, when the U.S. military landed on the Yaeyama Islands in December 1945, they were prepared to deal with malaria and other infectious diseases. They organized the Yaeyama Islands’ government under U.S. military rule, and with Japanese physicians, reconstituted the Malaria Eradication Office. The main concern was how to recover from the tragedy of the War Malaria Incident. It is noteworthy that the leaders of Yaeyama in the postwar period were all medical doctors. The second president of the Yaeyama Islands, Yoshino Kozen, and the second chief of the Malaria Eradication Office, Ohama Shinken—both of whom took office after their respective predecessors’ brief tenures—had close connections with colonial Taiwan. Both of them graduated from the Taihoku Medical College, and Ohama, who had studied parasitology in Taiwan, continued to research malaria and other parasitic diseases in Yaeyama, earning his doctorate from Taihoku Imperial University in 1942.

Based on his research on anopheles mosquitoes in Yaeyama, Ohama planned to control malaria by anti-vector methods, arguing that the anti-parasite approach before 1945 had been a failure. Meanwhile, Kuroshima Naoki, former chief of the Malaria Eradication Office, studied the application of DDT for anopheles control with the U.S. military government. DDT was subsequently employed for malaria eradication in Yaeyama.

To raise funds for the anti-malaria effort, Ohama proposed a new tax in 1947. The proposal was rejected by the local legislature because Yaeyama’s economy had not yet recovered; instead, the legislature passed malaria eradication regulations that would consider penalizing anyone failing to participate in the eradication program. The regulations of 1947 were very similar to the pre-1945 regulations, and were in fact based on the regulations of colonial Taiwan. The 1947 regulations authorized the Malaria Eradication Office to mobilize residents for the eradication efforts which successfully reduced the malaria infection rate in Yaeyama from 53.30% in 1945 to 25.32% in 1946, and to 17.08% in 1947. It must be pointed out that in the eradication campaign, Ohama emphasized the importance of the reorganization of the social system to support the anti-malaria program, as in the case of colonial Taiwan. He stated:

Malaria has been a cancer for the development of Yaeyama. We must revise the method for malaria eradication. I do object to the freedom of malaria patients to choose whether or not to receive treatment. I think that we need a regulation enforcing malaria control. For the development of Yaeyama and malaria eradication, enforcement is very important. For malaria control in Yaeyama, minor sacrifices must be accepted.

These developments provided the background for a new migration program from Okinawa to Yaeyama in the 1950s. The migrants were peasants who had lost agricultural land owing to the enlargement of U.S. military bases in Okinawa. The Yaeyama Islands government accepted the plan for development, believing that the efforts of Ohama and the Malaria Eradication Office had already sufficiently reduced malaria infection. But since the migrants were to be relocated to a prewar malarious district, the most important issue was still malaria control. In fact, there was a resurgence of malaria in the 1950s because of the migration policy; figures for malaria patients tell the story: 1,615 in 1953, 2,039 in 1954, 1,865 in 1955, and 2,211 in 1956. To deal with the malaria problem, the United States Civil Administration of Ryukyu (USCAR) initiated the Wheeler Plan for malaria eradication in Yaeyama and Miyako.

The Wheeler Plan and the U.S. Model

Charles M. Wheeler was a medical officer of the 406 Medical Institute of the U.S. Army. He investigated the situation in Yaeyama in August 1957 and began a malaria eradication program based on DDT residual spraying. Under the Wheeler plan, the Yaeyama Public Health Office oversaw the work of the Malaria Eradication Section, the chief of which in turn directed the anti-malaria activities of seven units, three in Ishigaki, and one each in Inoda, Kabira, East Iriomoto, and West Iriomoto. The plan was carried out with financial support from the United States Civil Administration of Ryukyu. A study of Yaeyama’s malaria eradication plan from July 1955 to June 1960 reveals that from 1957 to 1960, U.S. government subsidies, in the form of medicines, equipment, travel and general allowances, constituted the lion’s share of the total budget.

The Wheeler plan was divided into three phases: the attack phase from August 1957 to June 1962; the consolidation phase from July 1962 to July 1963; and the maintenance phase from July 1963 to July 1965. The main thrust of the attack plan was residual spraying of high doses of DDT in all of Yaeyama. As discussed earlier, the Ryukyu government also tried DDT spraying, but Wheeler believed that the method used in the earlier attempt was inadequate and would not eradicate malaria. The characteristic of the Wheeler plan was to target every building, and the level of DDT used was high. Blood tests were ended and residual spraying began in March 1958.

The Wheeler plan essentially followed the approach developed by the U.S. after World War II. The U.S. military used DDT when needed at battlefields all over the world during the war. After the war, the first experiment of malaria eradication was carried out in Italy under the support of the United Nations Relief and Rehabilitation Administration (UNRRA). The Malaria Committee of the United Nations (UN) then followed with malaria eradication by DDT residual spraying in Greece and Sri Lanka. The apparent successes led the UN to embark on a global malaria eradication program in 1956. In Taiwan, the Nationalist government’s malaria eradication program was supported by WHO and the U.S., and the success was certified by WHO in 1965.

At the WHO conference on malaria eradication in Manila in 1954, Morishita Kaoru was the only Japanese malariologist present. A former professor of the Institute for Tropical Medicine, Taihoku Imperial University in Taiwan before 1945, he became a professor of the Institute for Bacteriological Disease, Osaka University after the war. At the conference, he discussed the anti-malaria experience of colonial Taiwan, and concluded that the anti-anopheles approach of DDT residual spraying was much more effective than the anti-parasite method of blood tests and the use of quinine. Morishita’s work served to highlight the importance of the anti-anopheles method in the field of tropical medicine.

DDT residual spraying indeed proved to be the most effective method for malaria eradication in Yaeyama. As Yaeyama is a very small group of islands, malaria control was perhaps easier than in other tropical regions. But the timing and the supportive system for the anti-malaria program were also very important. On the issue of timing, many scholars in Yaeyama had already found out that anopheles mosquitoes were becoming resistant to DDT, but they believed that the mosquitoes could be controlled by high levels of DDT residual spraying within a few years. At the same time, the number of migrants to Yaeyama from Okinawa had decreased during the time of the Wheeler plan.

It must be noted that the supportive social system established by Ohama Shinken for malaria control—for example, the mobilization of residents to report malaria patients and anopheles mosquitoes, and to take part in deforestation efforts for the control of mosquitoes—was continued under the Wheeler plan. As discussed earlier, this system had its origin before World War II in the anti-malaria efforts in Taiwan. Many scholars have concluded that malaria eradication in the Yaeyama islands had been achieved through DDT residual spraying alone under the Wheeler Plan. But we should point out that DDT residual spraying was supported by the prewar social system based on the Taiwan model established during Ohama Shinken’s anti-malaria activities.

The success of the Wheeler Plan is illustrated by the results of microscope inspection of malaria parasites from 1953 to 1964. In 1953, there were 1,615 patients in a population of 48,642 who carried the parasites. By 1960, there were only four patients in a population of about the same size. In 1961, malaria was declared eradicated in the Yaeyama islands, and the long history of anti-malaria struggle came to an end.

Conclusion

The story of the struggle between malaria and human beings is central to the history of Yaeyama. Migration prompted by developmental policies was the most important background factor in the prevalence of malaria from the era of the Ryukyu Kingdom to the twentieth century and as discussed, the migration policy to expand rice production in Yaeyama is a good case in point. The eradication of malaria in Yaeyama is interesting and important in the world history of malaria. The process of malaria eradication in Yaeyama involved employing the Taiwan model at the beginning and then changing to the U.S. model after the war. Essentially, it represented a changeover from the anti-parasite method using quinine to the anti-anopheles mosquito method using DDT, and was related to advances in malaria studies in the field of tropical medicine.

The method and technology for malaria eradication in Yaeyama were imported from colonial Taiwan from the 1920s and involved the administration of blood tests and quinine to all persons in Yaeyama. Based on malaria studies in colonial Taiwan, many scholars thought that the anti-anopheles method was more effective than the anti-parasite method, but the latter was adopted owing to fiscal difficulties as well as the strong influence of the Taiwan model. In Yaeyama’s case, the method and technology were thus imported from the colonies to Japan proper; this was a very important case in the history of Japanese colonial medicine.

After the War Malaria Incident, Ohama Shinken, head of the Malaria Eradication Office of the Ryukyu government under U.S. military rule, emphasized the importance of the anti-anopheles method as well as the role of a supportive social system for malaria eradication based on the Taiwan model. The Wheeler plan which was implemented in 1957 used DDT residual spraying against the anopheles mosquitoes and the program was supported by the social mechanism established by Ohama. The Wheeler plan was part of a global anti-malaria program which included postwar Taiwan. The process of eradicating malaria in Yaeyama was based on advances in malaria studies in the twentieth century and it also reflected the change of regime in the islands, from Japanese to U.S. rule.