Effects Of Air Temperature And Reservoir On The Incidence Of Epidemic Hemorrhagic Fever In Huludao City And The Construction Of Structure Equation Model In Huludao City,2008-2018

Objective:Hemorrhagic fever with renal syndrome(HFRS)is a Class B legally reported infectious disease in mainland China.As a natural epidemic disease caused by Hantavirus and which is mainly caused by rodents,HFRS is affected by the meteorological factors.This study aims to explore the relationship between air temperature,reservoir factors and HFRS incidence in Huludao City,Liaoning Province,and to provide some evidence and method for the prevention and control of HFRSMethods:The HFRS incidence data in Huludao City from 2008 to 2018 was collected from the Chinese Disease Prevention and Control Information System.Density of rodents and virus-carrying rate data were provided by the City Center for Disease Control and Prevention.The air temperature data were retrieved from the Meteorological Information Service Center of the China Meteorological Administration.Correlation analysis and Structural Equation Modeling were adopted to investigate the relationship between temperature,reservoir factors and the HFRS.The significance level of correlation analysis was set 0.05.The structural equation model employed the insignificant fitting chi-square value,Root Mean Square Error of Approximation less than 0.08,Goodness-of-fit Index greater than 0.9,Comparative fit Index greater than 0.9,Normed fit Index greater than 0.9 to evaluate the fitting of the models.According to the structural equation model coefficient,the direct effect and indirect of each index on the incidence were calculated.Correlation analysis was performed using statistical software SPSS 19.0,and the structural equation model was constructed using the software LISREL 8.51Results:In spring,the highest monthly air temperature was most correlated with the incidence of two months lag,the correlation coefficient was 0.58(P<0.01),and the incidence rate was most relevant to the density of the residents in the three month lagged,with a correlation coefficient of 0.61(P<0.01).In summer,the incidence rate was most correlated with the density of rodents in the residential area after two month,and the correlation coefficient was 0.65(P<0.01).The highest monthly air temperature was most correlated with the incidence of lag three months,the correlation coefficient was 0.386(P<0.05),and the highest monthly air temperature was most correlated with the density of rodents in the residential area with a lag of one month.The correlation coefficient was 0.64(P<0.05).In autumn,the highest monthly temperature was most correlated with the incidence of two months lag,the correlation coefficient was 0.58(P<0.01),and the incidence rate was not related to the density of rodents and the virus-carrying rate.In winter,the lowest monthly air temperature was most correlated with the incidence of one-month lag,the correlation coefficient was-0.40(P<0.05),and the incidence rate was the most correlated with the density of rodents in the residential area with a lag of one month with the correlation coefficient 0.56(P<0.01).The structural equation models with two latent variables and three latent variables both could characterize the relationship between air temperature,reservoir factors and the HFRS incidence.In the two-latent-variable model from July to December,the highest air temperature in summer had a positive effect on the rodent density in the residential area,but had a negative effect on the Virus-Carrying Rate of rodents in the residential area and the field.In the two-latent-variable from May to July,both air temperature and reservoir variables were significant,indicating that the highest air temperature in spring and the reservoir had a positive effect on the HFRS incidence from May to July.The three-latent-variable model also indicated that air temperature had a positive effect on HFRS incidence.In the three-latent-variable model from November to January,the highest air temperature was positively correlated with the HFRS incidence by affecting the density of rodents.Conclusion:Air temperature was positively correlated with the density of rodents.The epidemic situation(rat density,rat poisoning rate)in the rodent population had a positive impact on HFRS incidence.Air temperature and reservoir could affect the transmission of HFRS in Huludao City,Liaoning Province,and showed the seasonality.The prevention and control of HFRS should give more consideration to the climate change and seasonal reproductive dynamics of reservoir host.