Epidemic characteristics and tendency prediction of hemorrhagic fever with renal syndrome from 2005 to 2014 in Xi'an

Abstract

Objective To analyze the epidemiologic characteristics and tendency of hemorrhagic fever with renal syndrome (HFRS) in Xi'an from 2005 to 2014, and to grasp the epidemic regularity and predict the trend of HFRS for establishing effective prevention and control measures. Methods The descriptive epidemiological method was used to analyze the epidemic situation of HFRS in Xi'an from 2005 to 2014. The autoregressive integrated moving average (ARIMA) model was applied to analyze, fit and predict the epidemic data of 2015. Results There were 8 500 HFRS patients in Xi'an from 2005 to 2014, the incidence rate was 10.60/100 000. The morbidity increased at first and then decreased from 2005 to 2014; the incidence rate was 9.06/100 000 in 2005 and up to 19.46/100 000 in 2010, then down to 3.43/100 000 in 2014. More cases were reported in spring (15.85%, 1 347/8 500) and autumn-winter seasons (72.91%, 6 197/8 500). The high-risk age group of HFRS was between 15 to 59 years, accounting for 77.71% (6 605/8 500) of the overall incidence rate; there were no significant differences in 59 years groups (χ2 = 15.63, P > 0.05). The male to female ratio was 3.01 : 1.00, male incidence was 15.57/100 000 and female incidence rate was 5.41/100 000, and the difference was statistically significant between gender (χ2 = 1 948.84, P < 0.05). The main occupation was farmers, accounting for 66.04% (5 613/8 500) of the overall incidence rate. The top 4 districts were Chang'an, Zhouzhi, Huxian and Lintong; the incidence rate was 31.07/100 000, 22.74/100 000, 21.09/100 000 and 11.06/100 000, respectively, and the 10 years cumulative incidence rate was higher than the total incidence. The monthly incidence was predicted with ARIMA (1, 1, 0) × (0, 1, 1)12 models in Xi'an from 2005 to 2014, and the predicted number of cases was 235 in 2015 (lower than 2014). Conclusions The overall trend of the epidemic has continued to fall but slowly. Positive and effective comprehensive measures should be taken to maintain the incidence of hemorrhagic fever at a lower level. Key words: Hemorrhagic fever with renal syndrome; Epidemiologic studies; Forecasting