| Objective: In order to clarify the epidemic characteristics and evolution of cases of SFTS in Anhui province,and explore the influence of meteorological factors on the onset time,so as to provide the basis for scientific and accurate prevention and control of SFTS.Method: Data of SFTS cases in Anhui Province during 2011-2021 were obtained from the China Disease Prevention and Control Information System,data of permanent residents in Anhui Province during 2011-2021 were obtained from the Anhui Bureau of Statistics,and meteorological data of Hefei City in Anhui Province during 2016-2021 were obtained from the National Meteorological Science Data Sharing Service Platform.Use Excel 2019 to sort out the data and establish the case database and meteorological database;Map Inof 16.0 software was used to draw hotspot map,SPSS 23.0 software was used for statistical description and analysis of epidemic characteristics and rules of cases.R software was used to build a distributed hysteresis nonlinear model to analyze the influence of meteorological factors on the occurrence of SFTS.Results: A total of 3785 cases were reported in Anhui Province from 2011 to 2021,with an average annual incidence of 0.57 per 100,000.There were 1816 male cases(47.98%)and 1969 female cases(52.02%).The median age was 64.00(53.00,71.00)years.The 65-69 age group had the highest number of cases with 674(17.81%).Most of them were farmers,with 3218(85.02%)cases.A total of 90 counties and districts in 15 prefectures reported SFTS cases,87.56%(3314/3785)of the cases were from Lu ’an City,Chuzhou City,Anqing City,Hefei City and Maanshan City.Among them,130 cases died and the overall case fatality rate was 3.43%.Among the deaths,60(46.15%)were males and 70(53.85%)were females.The median age was 68.00(61.00,74.00)years old.83.85%(101/130)were farmers.The fatality rate in Ma’anshan(13.88%)and Hefei(6.71%)was high.The death time mainly concentrated in April to August.The median time between onset and diagnosis of 2052 confirmed cases of SFTS was 7.00(4.00,11.00)days,and varied by year(H=236.259,P< 0.001)DLNM results showed that the weekly mean temperature was approximately inverted U-shaped for the risk curve of SFTS.When the weekly mean temperature was near 20.43℃,the maximum RR was 1.373(95%CI: 1.198-1.575,lag0-10 weeks).It was found that low temperature(2.27 ℃ and 8.60 ℃)showed a monotonically increasing trend on the distribution of SFTS,while high temperature(24.62℃ and29.49℃)showed a higher risk of SFTS,and the effect showed a decreasing trend with the extension of time.The cumulative effect of different temperatures showed that low temperature had a long-term protective effect,while high temperature had a short risk effect.The maximum cumulative RR was 1.614(95%CI: 1.172-2.222)..The influence of weekly mean humidity on SFTS showed an inverted U-shaped curve.When the weekly mean humidity was near 70.23%,the RR reached a peak of2.549(95%CI: 1.433-4.534),and then began to decline,and the relative risk was high at 66.32%-77.64%(P<0.05).The week lag effect distribution was significantly different.The distribution of lag effect was inverted U-shaped at low humidity(70.60%),and RR reached its peak at the lag5 week(RR=1.165,95%CI: 1.078-1.258).At higher humidity(84.07%),the distribution of effect showed a "U" shape,mainly showing the protective effect.The cumulative lag effect was analyzed and found that low humidity(70.60%)had statistical significance at lag(0-6)weeks and lag(0-10)weeks,and the maximum cumulative RR was 2.540(95%CI: 1.438-4.488,lag(0-10)weeks);Higher humidity(84.07%)had a protective effect(P<0.05).Extremely high humidity(90.19)had a protective effect only after lag(0-10)weeks(RR=0.376,95%CI: 0.191-0.741).The influence of weekly mean air pressure on the incidence of SFTS showed an inverted "U" shaped distribution.The RR first increased with the increase of air pressure,reached a peak at 1009.61 h Pa(RR=1.093,95%CI: 1.195-3.900,lag0-10weeks),and then rapidly decreased,showing a protective effect.The weekly lag effect of different barometric pressure was different.The low air pressure(997.10 h Pa,1003.37 h Pa)had the highest weekly relative risk(RR=1.367,95%CI: 1.012-1.848;RR=1.064,95%CI: 0.884-1.281).However,the distribution of effect of high air pressure(1018.80 h Pa,1026.05 h Pa)showed an upward trend,and RR reached its maximum at the lag10 th week(RR=1.198,95%CI: 1.030-1.393;RR=1.426,95%CI:0.914-2.224).Analysis of cumulative lag effects showed that the extreme low(997.10 h Pa)had a hazardous effect only in that week(RR=1.367,95%CI:1.012-1.848).However,high atmospheric pressure(1018.80 h Pa,1026.05 h Pa)had a protective effect on the cumulative effect of SFTS throughout the lag time,and gradually increased with the extension of time(P< 0.05).Conclusion: The number of cases reported by SFTS showed an increasing trend year by year.The middle-aged and elderly people living in rural areas of central Anhui Province had the highest incidence,and the highest incidence season was from summer to autumn.Temperature,humidity and air pressure are correlated with the occurrence of SFTS,and the hysteresis effect of temperature and humidity is obvious.Health authorities should strictly implement the prevention and control of SFTS in key areas and key populations,and pay attention to the role of meteorological factors such as temperature,air humidity and air pressure in the transmission process of SFTS.The early warning work of SFTS should be carried out,timely reminding residents to avoid activities in tick breeding sites in high temperature,high humidity and low pressure weather,and guiding residents to take personal protective measures when going out to work. |
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