ISSN 1003-8280 CN 10-1522/R 中国疾病预防控制中心 主办
Objective To describe the procedure of building Elman neural network model, and explore the value of potential application of the above model. Methods Monthly incidence of hemorrhagic fever with renal syndrome(HFRS) in China from 2004 to 2013 was used to build Elman neural network model and SARIMA model and forecasted the monthly incidence of HFRS in China from January 2014 to September 2014. The fitting and prediction effects of the two models were compared. Results For training sample, MAE, MAPE and RMSE of Elman neural network were 0.0088, 0.1191 and 0.0127 respectively; MAE, MAPE and RMSE of SARIMA model were 0.0111, 0.1268 and 0.0206 respectively. For predicting sample, MAE, RMSE and MAPE of Elman neural network were 0.0079, 0.1180 and 0.0096 respectively; MAE, RMSE and MAPE of SARIMA model were 0.0178, 0.2778 and 0.1861 respectively. Conclusion Elman neural network fits and forecasts the HFRS incidence trend in China well, and the fitting and prediction effect is superior to the SARIMA model, which is of great application value for the prevention and control of hemorrhagic fever with renal syndrome.
Objective To analyze the epidemiological features of hemorrhagic fever with renal syndrome (HFRS) and associated environmental risk factors for HFRS and associated environmental risk factors for HFRS in Liaoning province, China during 2005-2007, and to provide a scientific basis for HFRS control measures. Methods The epidemic data of HFRS in Liaoning province were collected. Analysis was performed to determine the correlation between the epidemic features of HFRS and environmental factors such as mean temperature, relative humidity, rainfall, sunshine, urban rodent density, rural rodent density, and virus?carrying rate. Results There were 7298 cases of HFRS in Liaoning province from 2005 to 2007, and 78 of them died. The mean annual incidence of HFRS was 5.78/100 000, and the mortality was 0.06/100 000; the incidence and mortality were higher in males than in females; 59.55% of the cases and 69.23% of fatal cases were aged 35-60 years; 61.98% of the cases and 56.41% of fatal cases were farmers. The peak of incidence appeared mainly in November to January and March to May, while the trough period was in July to October, showing the seasonal characteristics in mixed epidemic area; the mean annual incidence of HFRS was relatively high in the cities of Benxi (13.70/100 000), Huludao (12.92/100 000), Jinzhou (11.30/100 000), Dandong (10.21/100 000), and Fushun (9.84/100 000). The incidence of HFRS was negatively correlated with temperature but positively correlated with rainfall, rural rodent density, and virus-carrying rate; the Spearman rank correlation coefficients were -0.351, 0.400, 0.449, and 0.377, respectively, and the P values were 0.023, 0.009, 0.003, and 0.016, respectively. Conclusion In Liaoning province, HFRS is prevalent mainly in winter and spring and among young male farmers. The prevalence of HFRS is closely related to temperature, rainfall, rural rodent density, and virus-carrying rate in the same year.
【Abstract】 Objective To study the relationships of meteorological factors, animal host and hemorrhagic fever with renal syndrome (HFRS) incidence, and construct mathematical model for the forecast of HFRS. Methods Firstly, air pressure, air temperature, relative humidity, precipitation, sunshine duration and sunshine percentage were selected from all meteorological factors of Huludao city. Secondly, Pearson, Kendall and Spearman correlation analyses were used to describe the relationships among meteorological factors, animal host situation including rodent density and viral carriage of rodents and HFRS incidence. Thirdly, Bayesian discrimination analysis (BDA) was adopted to forecast HFRS incidence on the premise of meteorological factors and animal host formation as explanatory variables. Results There was the close relation between rodent density and annual HRFS incidence(r=0.738, P=0.000), and the rodent density was also influenced by sunshine duration, sunshine percentage and precipitation. A positive correlation was found between rodent density and sunshine time(r=0.494, P=0.016), and the correlation between rodent density and precipitation was negative(r=-0.350, P=0.101). The step wise BDA and all variables discrimination analysis had all good effect on the forecasting of HFRS based on meteorological factors and animal host data. The accuracy rate of fitting and leave?one?out (LOO) cross-validation of stepwise BDA all reached 82.6%(19/23) , however, that of fitting of all variables BDA was 90.9%(20/22) and 81.8%(18/22) for LOO cross-validation. For next year incidence prediction, the accuracy rates of fitting and LOO cross-validation step-wise were all 86.4%(19/22) for step-wise BDA, while for all variables BDA, its accuracy rate of fitting was 100%(21/21) and that of LOO cross-validation was 57.1%(12/21). Conclusion HFRS incidence was related to animal epidemic situation which was influenced by meteorological factors. Stepwise BDA offered useful information in the discrimination and forecasting of HFRS incidence, which had a good application in the future.