ISSN 1003-8280 CN 10-1522/R 中国疾病预防控制中心 主办
Objective To analyze the epidemiological characteristics and changing trend of scrub typhus cases in Guangdong province, China from 2012 to 2018, to predict the incidence trend, and to provide a scientific basis for evaluating the prevention and control measures of scrub typhus. Methods The data of scrub typhus cases in Guangdong province from 2012 to 2018 were collected. A descriptive epidemiological analysis was conducted. A seasonal autoregressive integrated moving average (ARIMA) time series model was used to establish a forecasting model, which was evaluated by comparing the observed and predicted values in 2019, and the incidence of scrub typhus in Guangdong province in 2020 was predicted using the model. Results A total of 33 490 scrub typhus cases were reported in Guangdong province from 2012 to 2018, with the incidence increasing year by year, and the cases mainly occurred in June to October. The incidence was highest in the 50-60 years group; there were more cases in females than in males, and farmers (65.49%) were the dominant occupation. The ARIMA (1,1,1)(0,1,1)12 model was fitted with the monthly case data; the Bayesian information criterion was 879.36; the residual sequence was white noise sequence according to the Ljung-Box test, and the adjusted R2 value was 0.377. The fitting effect of the model was good. The actual value in 2019 was basically consistent with the predicted value with 95% confidence interval; the model had a good predictive effect. Conclusion The scrub typhus incidence shows an increasing trend year by year in Guangdong province. The main susceptible populations were people aged 50-60 years, females, and farmers. The ARIMA model can be used to predict the changes in scrub typhus cases in Guangdong province well, suggesting that the relevant departments should strengthen the publicity and education of key population and the epidemic prevention and control in the season with high incidence of scrub typhus.
Scrub typhus is an acute febrile vector-borne infectious disease caused by Orientia tsutsugamushi. It is transmitted by the bite of chigger mite larvae. Now scrub typhus is a relatively serious public health issue in the Asia-Pacific region, threatening the health of more than one billion people worldwide. China is one of the countries with relatively serious burden of scrub typhus. In recent years, there has been an increasing trend in the epidemic areas of scrub typhus and the number of infected cases. With the development of "3S" spatial information technologies represented by geographic information system (GIS), remote sensing (RS), and global positioning system (GPS), many scholars have applied these technologies to studies on the spatial epidemic pattern of scrub typhus. This article mainly introduces the epidemiological characteristics and spatiotemporal dynamic trends of scrub typhus domestic and overseas, as well as the natural environmental factors and socioeconomic factors affecting the epidemic of scrub typhus, and focuses on the roles of spatial statistics and GIS technology in the epidemiological study of scrub typhus, so as to provide a reference for the future epidemiological study and the prevention and control of scrub typhus.
Objective To analyze larval Aedes density of 23 surveillance provinces in China from 2015 to 2017, and to provide scientific evidence for the risk assessment, early-warning, and control of Aedes-borne diseases. Methods Aedes larvae density data were collected from surveillance provinces of the dengue fever central government transfer payments project between 2015 and 2017, and were analyzed in different years and regions by SPSS 20.0 and Excel 2007 softwares. Results During the study period(2015-2017), the Breteau index(BI) in Hainan throughout the years, Zhejiang and Fujian during April to November, Guangxi during April to September, and Yunnan during June to October, were higher than 5, the Dengue virus transmission threshold, and reached dengue transmission risk level. The Mosq-ovitrap index(MOI) in Guangxi during April to October and Guangdong during March to November, were higher than 5, and showed the same trend as BI surveillance. The BI in Chongqing, Anhui, Jiangxi, Henan, Hubei, and Sichuan during most of surveillance months from May to October were higher than 5; Furthermore, BI in Henan and Hubei in most surveillance months were higher than 10, and reached dengue outbreak level. BI in Shanghai and Hunan during most surveillance months from May to September were higher than 5. BI in Hebei during June to September 2016 to 2017, and that in Shandong during July to September 2017 were higher than 5. BI during June to September 2016 and in May 2017 in Shaanxi were all greater than 5. Conclusion The dengue transmission risk varies in different provinces temporally. Overall, the category 1 provinces in southern parts of China including Guangdong, Yunnan, Guangxi, Hainan, Fujian, and Zhejiang have relatively high risk than other provinces. It is suggested that Aedes surveillance, risk assessment, early-warning, prevention and control should be strengthened in key provinces especially in south China for fostering the prevention and control of Aedes-borne diseases in the future.