Epidemiological Characteristics And Regional Risk Prediction Of Hemorrhagic Fever With Renal Syndrome In Shandong Province

Hemorrhagic fever with renal syndrome(HFRS)is a typical natural epidemic disease,whose major source of infection is the rodent-dominated host animal.The population is generally susceptible.And the major route of transmission are directly bitten by the rodent with virus or wounds are infected by contacting urine,feces,saliva,etc.HFRS is widely prevalent throughout the world,covering more than 70 countries on five continents.The major epidemic areas are concentrated in Europe and Asia.China is the most seriously harmed country.More than 90%of HFRS cases are reported in China every year.In the 1980s-1990s,the number of HFRS cases in China increased rapidly,especially in Shandong Province.The incidence of the disease was reported to be the first in the country and it was one of the most important epidemic areas.Moreover,patients with HFRS are generally in critical condition,with high mortality and great harm.After years of vaccine immunization and the management of key epidemic areas,the HFRS epidemic in Shandong Province has been controlled to a certain extent.However,in recent years,the situation of HFRS epidemic prevention and control is still very serious and is a serious public health problem.In the context of globalization and climate change,the mode of transmission and the epidemiological distribution of infectious diseases have also changed.The research on the relationship between diseases and environmental factors has done a lot of research,and the application methods and incorporation of variables are varied.Acquiring relevant influencing factors and high-incidence areas for diseases can provide a theoretical basis for early prevention and monitoring of the disease.The descriptive epidemiological analysis of the HFRS data from 2005 to 2015 in Shandong Province was applied,and described the epidemiological characteristics,epidemic type changes,and epidemiological trends of the disease through its three distributions.Using spatial scanning and spatio-temporal scanning to obtain high-incidence areas and time of HFRS in Shandong Province.The maximum entropy niche model was used to explore the main influencing factors including socio-economic factors,geographical factors and meteorological factors.And the horizontal and vertical risk predictions were made,namely the prediction of potential high-risk areas for HFRS in Shandong Province,which could break the limitation of the division of epidemic in administrative regions.These results could provide the theoretical basis for targeted prevention and control strategies and measures.Main results:1.There were a total of 15077 HFRS cases and 194 deaths in Shandong Province from 2005 to 2015.The mortality rate was 1.28%and average incidence rate was 1.44/100000,and the incidence rate in 2005-2006 and 2012-2014 exceeded 1.5/100000;HFRS undergone an transformation of double peaks-double peaks dominated by autumn and winter-double peaks over the study period.HFRS cases included 10898 cases of males and 4179 cases of females,with a sex ratio of 2.61:1;HFRS occurred in any age group,but 30-70 year-old age group accounted for 78.44%of the total cases(11825 cases).Farmers are high-risk occupations,accounting for 83.23%(12549 cases)of the total HFRS cases.2.The results of HFRS spatial scanning and spatio-temporal scanning of Shandong province from 2005-2015 showed that clusters were consistent with the actual high incidence areas,mainly distributed in the middle mountainous area and the southeastern coast area of Shandong province.And all counties of Weifang City belonged to the most likely cluster.Simple spatial scanning got a most likely cluster including Weifang City,Laiwu City,Qingdao City,Linyi City,Zibo City,Yantai City,Dongying City and Rizhao City(RR=4.64,P<0.001).And three secondary clusters were Jiaxiang County of Jining City(RR=1.83,P<0.01),Pingyi County of Linyi City(RR=1.74,P<0.01)and Jinxiang County of Jining City(RR=1.64,P<0.01),respectively.Spatio-temporal scanning analysis obtained a mostly likely cluster,including Weifang City,Qingdao City,Rizhao City,Zibo City,and Linyi City,with high occurrence time from 2011 to 2015(RR=3.37,P<0.01).The secondary clusters were respectively Jiaxiang County(RR=3.55,P<0.01),Jinxiang County(RR=3.69,P<0.01),of Jining City,form 2011 to 2015,and Pingyin County of Jinan City,from 2013 to 2014(RR=2.79,P=0.02).3.The maximum entropy niche model was used to make the vertical predictions on the risk areas of HFRS in Shandong province.The distribution of high-risk areas were basically consistent with the actual high-risk areas.The horizontal predictions were mainly composed of nine districts as sample sites in Shandong province,they were used to predict the incidence of HFRS in Shandong Province and the country each year,with relatively good prediction effect(AUC=0.761 in 2012).As far as forecasting results are concerned,the high-prevalence areas in Shandong Province are still located in the central and eastern coastal areas.In addition,the HFRS epidemic in the southwest region cannot be ignored.On a national scale,Shandong Province was still a key epidemic area,in addition to Shaanxi Province,Zhejiang Province,Jiangsu Province,Chongqing and some Sichuan Province were still severe.And there is a tendency to continue to spread to the South of China,corresponding prevention and control measures need to be implemented in a timely manner.Socio economic factors,including Defense Meteorological Satellite Program(DMSP),Gross Domestic Product(GDP)and population density,contribute a lot to the models,whose response curves were basically positively correlated with the risk of HFRS.Geographical factors such as Normalized Difference Vegetation Index(NDVI)in the third quarter,slope and aspect,and meteorological factors such as temperature and precipitation also had certain influence.Conclusions:1.The overall incidence of HFRS presented decline trend in Shandong Province during the study period.The high-incidence population is mainly young males,male cases are about 2.6 times of females.And the proportion of 30-70-year-old cases was larger,main occupations are mainly farmers.2.The spatial distribution of HFRS in Shandong Province was non-random during the study period.They were mainly distributed in the central mountainous areas and southeastern coastal areas of Shandong,and the trend manifested as high in the east and the north,low in the west and the south.The clusters included several districts and counties of Zibo City,Weifang City,Laiwu City,Qingdao City,Linyi City,Rizhao City,Jining City and other cities.Weifang city was a severe epidemic area.3.The maximum entropy principle niche model can be used to explore the main influencing factors of HFRS.At the same time,the regional incidence risk prediction of HFRS could be carried out,with good satisfaction after the verification for models.It can be used to guide the relevant departments of CDC to adjust the local conditions and reasonably configure the health resources to predict and control the disease.4.The maximum entropy niche model could be used for the vertical and horizontal prediction for risk of HFRS,with good satisfaction.The potential high-risk areas of HFRS would be obtained,and the major socio-economic factors,geographical and meteorological factors,and other factors those affect people affected by HFRS were identified.Prevention and control for this disease could be made based on predictive results.