Eradication of Schistosomiasis in Japan: Lessons for the Rest of East Asia

Eradication of Schistosomiasis in Japan: Lessons for the Rest of East Asia

Mitsuko Hasegawa (Institute of Tropical Medicine, Nagasaki University, Japan)
DOI: 10.4018/978-1-7998-1807-6.ch002

Abstract

According to the WHO, at least 220.8 million people needed preventive drug treatment for schistosomiasis in 2017. In addition to the major strategy of mass drug administration, other control measures are necessary. Japan previously had endemic areas of schistosomiasis, but it was eradicated. The purpose of this chapter is to introduce new information about the successful case in the Chikugo river basin in Kyûshû to the researchers and policy-makers who discuss the most suitable measures in the disease-endemic areas in developing countries. To collect historical evidence, literature was reviewed. To corroborate that with more focused oral history, interviews with local people were performed. Qualitative data was analyzed by creating a fishbone diagram. New knowledge was acquired on such issues as education methods and active community participation. Furthermore, there was a correspondence with the key elements of the global strategic framework of Integrated Vector Management recommended by the WHO. Some measures could be adapted to the conditions in the current disease-endemic areas.
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Introduction

The World Health Organization (WHO) emphasizes the importance of control of Neglected Tropical Diseases (NTDs). Among NTDs, schistosomiasis is reported to be found in at least 78 countries, most of which are developing countries and 220.8 million people in total required preventive drug treatment for schistosomiasis in 2017 (WHO 2019). In the past, Japan had endemic areas of schistosomiasis but it was eradicated within 100 years after the discovery of the causative parasite, Schistosoma japonicum in 1904. Of the previous endemic areas in Japan, the Chikugo river basin in Saga and Fukuoka prefectures in Kyûshû saw measures where local people, their communities and the local and national governments were all involved in eradicating the disease (Tsutsumi, 2005). No new patient has been reported since 1976 in this area (Tsutsumi, 1986).

Schistosomiasis has a terrible impact not only on individuals but also on society. For individuals, infection with S. japonicum, currently seen in China and the Philippines, brings high fever and bloody mucous stool in the acute phase and liver cirrhosis and ascites in the chronic phase, which can lead to death. If the eggs get clogged in cerebral blood vessels, neurological symptoms occur (Colley et al., 2014). Both S. mekongi distributed in Lao People’s Democratic Republic (Lao PDR) and Cambodia and S. mansoni in Africa, the Middle East and other areas cause symptoms similar to S. japonicum. One of the main symptoms of S. haematobium in parts of Africa and the Middle East is hematuria and often includes bladder cancer as a complication (Mostafa et al., 1999).

For society, as schistosomiasis passes into the chronic phase like other parasite infection, it hinders child development and also it decreases the work force when adults are infected (Aoki 2007). The current main stream of countermeasures for schistosomiasis is the large-scale treatment called Preventive Chemotherapy (WHO 2019). Oral administration drugs are distributed in a means of Mass Drug Administration (MDA), which also aims to interrupt transmission (WHO 2006). However, other preventive measures are also necessary as those who recover frequently get infected again (Ohmae et al. 2004, Nakamura 2007).

Accordingly, if potentially applicable measures in parallel with MDA in the current endemic areas in developing countries can be presented, using the successful case of the Chikugo river basin as a model, future control measures of schistosomiasis could be more effective. However, it is difficult to adapt Japanese measures to developing countries where environmental and financial situations differ. Particularly, the core of the control methods in the Chikugo river basin was eradication of the intermediate host snail, Oncomelania nosophora, or Miyairigai (gai [or kai] means snail in Japanese), by mostly cementing riverside areas and ditches, usage of molluscicides, and environmental modifications, which involved huge cost. This method is difficult in developing countries where funds and resource are not adequately ensured. Furthermore, Matsuda and Kirinoki (2005) wrote that the effect of usage of molluscicides and their influence on the environment needed to be carefully considered in the endemic areas of S. mekongi as the intermediate snail host lives in large rivers which local people also use in their daily lives. In addition, it is unfeasible to eradicate the intermediate snail host in the vast basin. In other words, it is estimated to be extremely difficult to implement measures for eradication of the intermediate host taken in the Chikugo river basin from both financial and environmental aspects.

Considering these, control measures in the Chikugo river basin were closely researched to find applicable methods for the control of schistosomiasis in the current endemic areas. Consequently, knowledge and awareness-raising activities for prevention (Saga 1991) and active community participation in the control measures (Tosu City, 2009) were confirmed.

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