Geographical survey of the intermediate host of Schistosoma japonicum: Toward precise management of Oncomelania hupensis.

Schistosomiasis caused bySchistosoma japonicumis a public health concern in China, and Hubei is one of the most affected provinces. Although the routine surveillance since the mid 1950s has generated substantial data pertaining to the habitats of the intermediate snail host,Oncomelania hupensis, its spatiotemporal distribution is not known. A review of local chronicles on the annual records of schistosomiasis control program was conducted to retrospectively collect information aboutO.hupensishabitats. The habitats were mapped by a field survey in 2016. We categorized the habitats into five evolutionary types, namely, Type I, current habitat; Types II-IV, historical habitat; and Type V, suspected habitat according to habitat development. The shape of habitats was determined using geographical information systems. A visual database was established and managed on the ArcGIS platform. A total of 43 472O.hupensishabitats, covering an area of approximately 430 000 hectares, were identified through the study. Over 60% of these habitats have been eliminated. The highest number ofO.hupensishabitats was recorded in 1975; however, most of them were preserved until 1995. Our study, for the first time, sheds light on the spatiotemporal distribution ofO.hupensisin the most affected province in China. The data will be valuable for policy making and for formulating strategies to eliminate schistosomiasis in Hubei Province. Author summary Schistosomiasis is a major infectious disease of humans and animals, and is a global concern. In China, it is endemically found across 12 provinces along the Yangtze River and in the area south of the river. According to the "13th Five-Year Plan for National Schistosomiasis Control", by the end of 2020, schistosomiasis epidemic will continue to decline towards eradication throughout China. However, the control and elimination of its intermediate snail host,Oncomelania hupensis, is crucial for blocking schistosomiasis transmissions in China. Therefore, further understanding, surveillance, and control ofO.hupensisdistribution is critical to protect the health of individuals in endemic areas and to formulate relevant prevention and control strategies in order to reduce the burden of schistosomiasis, and ultimately overcome this epidemic. In this study, we reviewed local chronicles and annual records and extensively surveyed Hubei Province to collect information on the historical, current, and suspected habitats ofO.hupensis. Subsequently, we used various geospatial tools (ArcGIS and Google Earth) to visualize the spatial distributions of habitats. Our study provides valuable data that will facilitate more effective habitat management of this intermediate host species and contribute to more precise management of schistosomiasis in China.