The Japanese Islands and Infectious Diseases :: Toyoko Kozai (Japan)

Let’s take a look at some satellite photos. Japan is an island country with a linear chain of a little less than 7,000 islands. Incredibly, about 70% of the country is mountainous and covered with forests. This topographical feature has a significant influence on the distribution and density of the population and on the extent of the transportation network. Naturally, these correlate with the epidemic patterns of human-to-human infections.

The spread of COVID-19 is no different: there are large regional disparities in the numbers of cases and deaths. As of April 20th, more than 10,000 infected cases (positive PCR tests) and 171 deaths have been recorded, but at the very same time, not a single case has been found in some areas such as Iwate Prefecture. When differences in epidemic patterns emerge, people’s conception of the disease and sense of urgency change accordingly. The fact that a single notion of this disease cannot be settled upon is one of the reasons why it is so difficult to steer a nationwide anti-infectious disease policy in Japan.

A Brief History of Smallpox in the Japanese Islands

Now, the history of smallpox is one interesting example of how diverse the epidemic patterns of infectious diseases can be in the Japanese archipelago. This infectious disease, which has had many episodes in world history, is said to have been introduced to the Japanese islands in the first half of the 8th century according to records. Smallpox was a greatly feared pestilence, as it caused a large number of deaths with each outbreak, and was interpreted as the will of the gods and the Buddha, or as the result of a failing government, or even as the work of a vengeful nobleman who died an untimely death. However, by the sixteenth century at the latest, smallpox had become endemic in densely populated areas of the country, spreading the epidemic to the surrounding areas.

In Kyoto, Osaka, and Edo, which each had populations of several hundred thousand people, smallpox became a disease that mainly infected young infants. The spread of smallpox became associated with the image of Hōsōshin (the god who infects people with smallpox) wandering around the city. People did not avoid smallpox, but rather regarded it as a kind of rite of passage and prayed that they would get off easy.

In regions somewhat removed from the cities, smallpox epidemics occurred somewhere between every few years to every dozen years. Similarly to urban areas, smallpox was known as a child’s disease, but here the Hōsōshin was captured as a figure who moves from region to region. When word came that there was a smallpox epidemic in neighboring regions, people would place Shimenawa purification ropes and other charms around the village boundaries and houses in order to ward off the disease.

Smallpox rarely spread to distant islands and remote mountainous regions, but when it did, the population and livelihoods were severely damaged. For this reason, in some areas it was customary to take the infected, even if they were a parent or sibling, to be left in some faraway place, or, conversely, to abandon the victims and run away.

The introduction of the cowpox vaccine, half a century delayed

Although the experience of smallpox differed by region in Japan, in most cases until modern times, medical treatment was only symptomatic. The “embryonic poison” theory (thatsmallpox poison occurs congenitally in the body and is drawn out by the bad spirits of the heavens to cause smallpox) which was introduced to Japan in the 16th century was widely favored, and doctors would prescribe medicines to strengthen and detoxify the body.

In the middle of the eighteenth century, the technique of variolation was introduced from the Asian continent but was never widely proliferated, handed down instead as a craftsman’s art. The one exception is the Ryukyu Kingdom (present-day Okinawa Prefecture). From the end of the eighteenth century to the latter half of the nineteenth century, the Ryukyus collected smallpox scabs from Satsuma (present-day Kagoshima Prefecture) once every 12 years as a national project. By pulling the poison out of their bodies before a natural epidemic occurred, they managed to avoid untimely outbreaks of smallpox.

The reason why the cowpox vaccine, which was announced in England in 1798, did not spread in Japan until 1849 is that the standard of care for a long time was a symptomatic treatment based on the theory of embryonic poison. Both doctors and patients regarded contracting smallpox once in a lifetime as inevitable. For the same reason, in urban areas where culture had matured around a coexistence with smallpox, there was never a high demand for variolation. In the mid-nineteenth century, it was the provinces that led the way in stocking up on the cowpox vaccine, where smallpox epidemics were out of control and often resulted in large numbers of deaths. After the Fukui and Saga clans began to order the cowpox vaccine as a clan project, the cowpox vaccine spread to many parts of the
archipelago. Ultimately, it was because smallpox was not uniformly prevalent in the Japanese archipelago that the cowpox vaccine was turned to as a measure by which smallpox could be controlled.

Countering infectious diseases in Japan

Looking back at the history of smallpox in Japan, we can see that even this single disease was not understood in a uniform way. In Japan, where the islands are arranged in a linear yet divided collection of mountains and seas, infectious diseases are spread in many different ways. If epidemic patterns differ, it follows that the conception of contagion, sense of crisis, countermeasures, and normative standards will change. From the Meiji period onwards, the Japanese government began to come up with stringent, uniform measures against infectious diseases throughout the country, but it was the diversity within the archipelago that caused them the greatest difficulty.

In the case of this pandemic as well, the Japanese government appears to be at more of a loss with dealing with the Japanese people than with COVID-19 itself. Each person has had a different set of experiences with infectious diseases, depending on the region in which they live. As a result, responses to the government’s requests have been mixed. No one knows for certain how this diversity or lack of unity will affect the development of this pandemic. But the history of infectious diseases in Japan shows us that, for better or worse, this diversity will continue to be a key element of combatting infectious diseases in the Japanese archipelago.

References

Toyoko Kozai, The Road to Immunization: A History of Smallpox in Early Modern Japan (Tokyo: University of Tokyo Press, 2019).

Rotermund H. O., Hôsôgami, ou, La petite vérole aisément: matériaux pour l’étude des épidémies dans le Japon des XVIIIe, XIXe siècles (Paris: Maisonneuve & Larose, 1991).

Toyoko Kozai is a researcher specializing in the history of medicine and medical sociology, and is an Associate Professor in the Department of Sociology at Bukkyo University in Kyoto. Her research examines the history of health policies surrounding medical hygiene and anatomical donation (such as body, organ, and blood donation) in hopes of seeding further analyses of medical practice and bioethics in contemporary Japan.

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The Teach311 + COVID-19 Collective began in 2011 as a joint project of the Forum for the History of Science in Asia and the Society for the History of Technology Asia Network and is currently expanded in collaboration with the Max Planck Institute for the History of Science(Artifacts, Action, Knowledge) and Nanyang Technological University-Singapore.