| Dengue fever is mosquito borne infectious disease,transmitted by Aedes aegypti and Ae.albopictus.In recent decades,the incidence of dengue fever in the global rise rapidly,the scope of distribution expands unceasingly,that has become a serious public health problem in many countries and regions.Since 2000,the incidence of dengue fever continues to rise in our country,which pandemic scale is the biggest in 2014 after 1986,the number of cases is 46864.Dengue fever has become a serious threat to public health in China.Dengue fever is related to the environmental factors closely,It is important to study the space-time distribution features of dengue fever and the correlation analysis of environmental factors associated with dengue fever,in order to finding the possible factors of epidemic.This study based on the analysis of the dengue fever outbreak in China and Guangdong province in 2011-2015,and explored the spatial-temporal characteristics of dengue fever analyzed the correlation between environmental factors and the incidence of dengue fever,to provide scientific reference for effective prevention and control of dengue fever strategies,the results will help to provide direction for the further research in the future.It was obtained the results as follow:1.Reported cases of dengue fever were 120,575,4663,46864,3858 in China in 2011-2015 respectively,corresponding,the incidence of dengue fever were 0.0089/100000,0.0427/100000,0.3444/100000,3.4582/100000,3.4582/100000,6 cases of dengue fever deaths were reported in 2014,and no deaths in the rest of the year.The number of cases of Guangdong province accounted for 89.67% of China during five years.2.Guangdong has always been the spatial primary clustering region for Dengue fever from 2011 to 2015 in our country.Other primary clustering regions include Hainan,Guangxi,Guizhou,Hunan,Yunnan,Jiangxi,Fujian,but these provinces are not primary clustering regions in every year.In the spatial-temporal clustering analysis from 2011 to 2015,the primary clustering region is Guangdong province and the clustering time is September and October in 2014.There are two secondary-level clustering regions,One is the Tibet,Qinghai,Xinjiang,Gansu,Sichuan,Yunnan province and clustering time is September and October of 2015;The other is Zhejiang,Shanghai,Fujian and the clustering time is September and October in 2014.All the p values of above clustering results are <0.01.It indicates that our Dengue fever mainly distributes in our southeast taking Guangdong as the center,southwest and part of northwest regions from 2011 to 2015.During this period of time,epidemic situation in Guangdong is the most serious in September and October of 2014,followed by Zhejiang,Shanghai and Fujian.In September and October 2015,Dengue fever spread to Tibet,Qinghai,Xinjiang,Gansu in the northwest as well as Sichuan and Yunnan in the southwest.3.It is indicated that primary clustering regions include Guangzhou city,Zengcheng city,Conghua city,Huadu district of Guangzhou city and Dongguan city in Guangdong dengue fever pure space clustering analysis in 2011.In 2012,primary clustering region is Foshan city.In 2013,primary clustering regions include Shunde district,Nanhai district of Foshan city,Foshan city,Panyu district of Guangzhou city,Jiangmen city,Zhongshan city,Heshan city and Guangzhou city.In 2014,the primary clustering regions include Guangzhou city,Huadu district of Guangzhou,Foshan city,Nanhai district of Foshan and Panyu district of Guangzhou city.In 2015,primary clustering region is Chaozhou city.p values of all above clustering results are <0.01.From 2011 to 2014,Guangdong Dengue fever mainly focuses in the central part of the province and the disease has been transferred to the eastern part of the province in 2015.4.In the 2011-2014 Guangdong Dengue fever results of case demographic analysis,the ratio between male and female is 0.9086:1,patients aged between 15 and 59 account for 75.50% of the total.People who worked at home,who are waiting for employment,retired people,business service people,medical staffs,workers and students account for 63.58% of the total workers.There is significant difference in age ratio of Dengue fever in 2013 and 2014 and there is no difference in other years.5.Spearman grade correlation analysis between metrological factors and dengue fever incidence in 2014 in each city of Guangdong was showed that meteorological factors and incidence regional differences of dengue fever are uncorrelated during the period of dengue fever epidemic,which indicates that meteorological factors is not the cause of the incidence differences among the cities of Guangdong province.The temperature has relation with the seasonal changes incidence of Guangzhou dengue fever,and rainfall has no relation with the incidence based on the meteorological factors and seasonal changes of incidence of Guangzhou dengue fever correlation analysis in 2013-1015.6.Spearman grade correlation analysis has been made for mosquito oviposition index among eatch city of Guangdong province and incidence of dengue fever during the period of dengue fever epidemic in 2014,which shows that there is no correlation between mosquito oviposition index and regional difference of dengue fever incidence in Guangdong and reminds that mosquito oviposition index is not the reason for differences of dengue fever incidence in each city of Guangdong.Spearman grade correlation analysis has been made for mosquito oviposition index in current month,one month as well as two months before in 2014 and adult mosquito density as well as Dengue fever incidence in Guangzhou city.The results have shown that correlation coefficient r values of mosquito oviposition index in current month,one month as well as two months before and Dengue fever incidence is 0.040,0.770,0.948 and the p values are 0.901,0.006 and 0.000 respectively.It indicates that there is significant positive correlation between mosquito oviposition index in one month and two months before and dengue fever incidence in current month.There is no correlation between mosquito oviposition index and incidence in current month,which indicates that mosquito oviposition index may be an important factor affecting the seasonal variation for dengue fever incidence of Guangzhou and the influence is with one month to two months hysteresis. |
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