Using Ecological Niche Models To Predict The Transmission Risk Of Hemorrhagic Fever With Renal Syndrome

Hemorrhagic fever with renal syndrome (HFRS), a rodent-borne viral disease caused by different species of hantaviruses, is characterized by fever, hemorrhage, and acute kidney injury. It is a serious public health threat in China where human cases account for90%of the total global cases. Since the first HFRS case was detected in1963, Hunan Province has become one of the most severe endemic areas in China, with more than90%of the cities have reported infections, and it has become a serious public health problem. The distribution, transmission and prevalence of HFRS are influenced by environmental factors such as geographic landscape, climate and human activities.In this study, data on human HFRS cases and environmental variables in midstream and downstream of the Xiangjiang River and Changsha were collected. Ecological niche models (ENMs) combined with geographic information systems (GIS) and remote sensing (RS) were used to analyze the spatio-temporal distribution of HFRS cases and identify the environmental risk factors and potential risk of HFRS transmission. The content and results were as follows:(1) The spatio-temporal distribution of HFRS cases showed a certain noteworthy characteristic. On time scale, HFRS incidence varied seasonally. In midstream and downstream of the Xiangjiang river, HFRS incidence was high in January, from April to June, and from November to December, but lower between August to October. In Changsha, HFRS incidence was high in January, from April to June, and from November to December, but lower between August to October. In midstream and downstream of Xiangjiang river the spatial cluster concentrated in the west (Wangcheng county, Changsha municipal district, Xiangtan county and Xiangtan municipal district). The spatial clustering of HFRS infections in Changsha concentrated in the west (Ningxiang county, Wangcheng County and Changsha municipal district), and northwest Liuyang.(2) We showed that the high risk of HFRS in midstream and downstream of the Xiangjiang river concentrated in the middle of the area (Wangcheng county, Changsha municipal district, Xiangtan county, Xiangtan municipal district, Zhuzhou county and Zhuzhou municipal district), and lower in south (Hengshan county and Hengdong county) and north (Xiangyin county and Miluo county). Moreover, in Changsha, the high risk of HFRS was mainly in west-central Changsha (Changsha county, Changsha municipal district, Wangcheng county and east Ningxiang county), and lower in Liuyang.(3) HFRS infection was closely associated with environmental variables. Meteorological factors (temperature and precipitation), normalized difference vegetation index (NDVI) and land use types have significance impact on HFRS transmission, both in midstream and downstream of the Xiangjiang river and Changsha. The highest HFRS incidence of HFRS was in districts where mean annual temperature is around18℃and annual precipitation is between1500mm and1600mm. Monthly NDVI values of areas predicted present is lower than areas predicted absent, with high seasonal variation. NDVI in May and July have significant influence on HFRS incidence. Cultivated land and urban land in particular are associated with HFRS incidence.In this study, we effectively explored the spatio-temporal distribution of HFRS cases and the environmental risk factors of HFRS transmission, and predicted the potential risk areas, which could provide theoretical basis for the prevention and control of HFRS. The method combined ENMs with GIS successfully strengthened the prediction both in the intensity of epidemic and transmission risk areas, providing reference for the investigation of other similar infectious diseases.