Japan’s Experience

【Japan’s experience with NTD elimination】

Japan was once an endemic country for NTDs such as lymphatic filariasis and schistosomiasis. The story of how researchers, national and local governments, and citizens worked together to eradicate these diseases—from the prewar to the postwar period—is not widely known. The oldest record of lymphatic filariasis in Japan is from the Heian period (794-1185), but the first official epidemiological survey was not conducted until 1912. These surveys revealed that lymphatic filariasis was highly prevalent in Hachijokojima Island, the Nansei Islands (Okinawa and Amami), and the southwest Kyushu region. In the 1950s, researchers primarily from the University of Tokyo, Kagoshima University, and Nagasaki University investigated the clinical pathology of lymphatic filariasis, methods for blood tests, methods for administering the antifilarial drug diethylcarbamazine (DEC) and managing its side effects, and mosquito vector control measures. A government-led project to eliminate filariasis was launched based on the success of those research efforts, and resulted in the successful elimination of lymphatic filariasis in a period of about 30 years. Schistosomiasis was once a feared endemic disease in the Kofu valley in Yamanashi Prefecture, the Katayama area of Hiroshima Prefecture, and the Chikugo River basin in Fukuoka Prefecture. The parasite that causes the disease (a blood fluke called Schistosoma japonicum) was discovered in 1904, and the intermediate host (a snail called Oncomelania hupensis) was identified in 1913. Both of these discoveries came from Japanese researchers. Once the transmission pathway had been identified, measures were taken to eliminate the disease by controlling the population of the intermediate host and making proactive efforts to properly dispose of fecal waste, treat affected people, and control parasite-carrying animals. Thanks to these efforts, the spread of schistosomiasis was stopped nationwide in the 1980s.