Epidemiological trends and outbreak characteristics of dengue fever in Yunnan Province,China,2013-2022
Objective To analyze epidemiological characteristics and outbreak of dengue fever in Yunnan Province,China,so as to provide a scientific basis for formulating effective prevention and control measures.Methods Relevant data on dengue fever cases and outbreaks reported in Yunnan Province during 2013-2022 were collected from the"Infectious Disease Surveillance System"and"Public Health Emergency Management Information System"of"China Disease Control and Prevention Information System".The concentration method was used to analyze seasonal characteristics.Excel 2007 software was used to sort out the data.MapInfo 7.8 software was used to draw the map.SPSS 26.0 was used to analyze the correlation,and the Chi-square test was used to compare the rate or composition ratio.The descriptive epidemiological method was used to analyze the epidemiological characteristics and outbreak response to dengue fever.Results A total of 16774 cases of dengue fever were reported in Yunnan Province from 2013 to 2022,including 11944 local cases,4521 overseas imported cases,and 309 domestic imported cases,with an average annual reported incidence of 3.53/100000.The disease showed a high incidence every other year.The concentration(M)was 0.84,showing strong seasonality.Imported cases mainly occurred from June to October,and local cases mostly from August to November.The male-to-female ratio of imported cases was slightly higher than that of local cases(χ2=37.596,P<0.001).The majority of local cases were 30～<40 years old(20.14%),and the majority of imported cases were 20～<30 years old(27.58%).The local cases were found in 5 border prefectures(cities).The overseas imported cases were mainly from southeast Asian countries and African countries,and Myanmar,Cambodia,and Laos were the main source countries(96.81%).The domestic imported cases were mainly from Xishuangbanna Dai Autonomous Prefecture(85.76%).The majority of cases were farmers,commercial service personnel,cadres/retirees,housekeepers,job-waiting people,and students.Commercial service personnel accounted for the highest proportion in local cases(21.89%),while farmers accounted for the highest proportion in imported cases(39.90%).There was a significant difference in occupational distribution between imported cases and local cases(χ2=1535.415,P<0.001).A total of 28 dengue fever outbreaks were reported from 2013 to 2022,including 1 major event and 27 general events.The number of reported cases accounted for 83.41%of the total number of cases,and each event involved an average of 499.71 cases.The median time from the onset of the first case to the verification of event occurrence was 7(5,9)days,and the median duration of the outbreak was 110(27,140)days.Twenty-five outbreaks occurred in villages/communities.Conclusions Dengue fever in Yunnan has obvious seasonal,aggregated,and regional distribution patterns.We need to further strengthen imported case management,disease vector surveillance and control,and the prevention and control of dengue fever in key areas.
Dengue feverEpidemiological characteristicOutbreakLocal caseImported case
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