我國流行性乙型腦炎時空分布特征及風(fēng)險預(yù)測研究
發(fā)布時間:2018-04-12 11:34
本文選題:流行性乙型腦炎 + 時空聚集區(qū)。 參考:《中國人民解放軍軍事醫(yī)學(xué)科學(xué)院》2014年碩士論文
【摘要】:背景: 流行性乙型腦炎(Japanese encephalitis, JE),簡稱乙腦,由乙型腦炎病毒(Japanese encephalitis virus, JEV)引起的急性中樞神經(jīng)系疾病,我國法定乙類傳染病。乙腦是一種蚊媒傳染病,通過被感染的蚊蟲叮咬而傳播,豬是其重要的擴增宿主,,遷徙的水鳥和蝙蝠等是主要的儲存宿主,并能攜帶病毒進行遠距離擴散。人對JEV普遍易感,感染后有較廣的疾病譜:輕癥可表現(xiàn)為無癥狀感染或是流感樣癥狀;典型患者以高熱、意識障礙、抽搐、腦膜刺激等神經(jīng)癥狀為主要特征;重癥患者可表現(xiàn)為呼吸衰竭甚至死亡。WHO最近研究顯示,亞洲和西太平洋地區(qū)超過24個國家存在乙腦的流行,全球每年約有67,900病例發(fā)生,其中50%發(fā)生在中國。 自20世紀(jì)70年代我國開始接種乙腦疫苗以來,乙腦發(fā)病率從1971年的20.92/10萬下降到2008年的0.23/10萬。目前,我國乙腦的控制已經(jīng)取得了舉世矚目的成就,但也存在一些不容忽視的問題。比如,我國沿海地區(qū)乙腦發(fā)病已經(jīng)得到有效控制,但云南、貴州、四川、廣西等地乙腦的發(fā)病率還較高,與WHO提出的在2015年將小于15歲兒童乙腦發(fā)病率控制在0.5/10萬以下的目標(biāo)還有一定距離。其次,JEV流行區(qū)域已經(jīng)擴大。曾經(jīng)被認(rèn)為是JEV空白區(qū)的西藏,已經(jīng)從三帶喙庫蚊體內(nèi)分離到基因I型病毒,在豬的血清標(biāo)本中檢測到IgM抗體和健康人的血清中檢測到中和抗體。再者,近年來我國各地時有乙腦暴發(fā),并呈現(xiàn)出一些新的特點:山西運城2006年7-8月乙腦暴發(fā),病死率高達28.8%,成年型病例增多(86%的病例是30歲以上的成年人),并且同時分離到基因I型和III型,而這些現(xiàn)象在以往的暴發(fā)中是未出現(xiàn)的。盡管我國乙腦發(fā)病數(shù)大幅下降,但是由于20-30%病人死亡,30-50%幸存者有神經(jīng)系統(tǒng)后遺癥,給家庭和社會帶來極大的精神和疾病負(fù)擔(dān),尤其值得注意的是乙腦是威脅云南兒童死亡的第二位傳染病。綜上可見,乙腦仍然是我國嚴(yán)重的公共衛(wèi)生問題。 近年來,空間信息技術(shù)得到迅猛發(fā)展,廣泛應(yīng)用于血吸蟲病、瘧疾、腎綜合征出血熱、蜱媒疾病和其他自然疫源性疾病的醫(yī)學(xué)地圖編制,探測時空分布規(guī)律、識別潛在的高風(fēng)險地區(qū)和危險因素分析等的研究中。目前我國乙腦流行特征的研究主要是對局部地區(qū)長期,或全國范圍內(nèi)短期監(jiān)測數(shù)據(jù)的分析,這就缺乏一個長期整體的認(rèn)識。我國乙腦整體的時空分布格局、熱點區(qū)域變遷問題、危險因素及風(fēng)險預(yù)測等方面的研究非常少,存在較大的空白。近年來,我國乙腦風(fēng)險預(yù)測的研究處于起步階段,并且是從大尺度上進行研究,只能提供一個整體的趨勢情況,精度欠缺,對于我國乙腦的靶向控制提供的參考非常有限。綜上所述,有必要了解我國乙腦小尺度上的時空分布格局,找出發(fā)病的熱點區(qū)域,分析高發(fā)區(qū)乙腦流行的主要影響因素,并預(yù)測我國乙腦的發(fā)生風(fēng)險,為乙腦防控提供科學(xué)依據(jù)。 目的: 了解我國乙腦的流行趨勢及變化特征,探討我國乙腦時空分布模式及發(fā)病的熱點區(qū)域。闡明不同高發(fā)區(qū)乙腦發(fā)生與環(huán)境因素的關(guān)系,識別其發(fā)生的主要驅(qū)動因素及其滯后作用。綜合分析氣象、地理和環(huán)境因素對我國乙腦發(fā)生的影響,建立高分辨率的乙腦發(fā)生風(fēng)險預(yù)測模型,評估乙腦發(fā)生的空間差異,為我國乙腦預(yù)防控制提供科學(xué)依據(jù)。 方法: 1.收集2002年1月-2010年12月全國各區(qū)縣每月監(jiān)測數(shù)據(jù),運用描述性流行病學(xué)方法分析我國乙腦發(fā)生和死亡病例的流行特征;將區(qū)縣發(fā)病數(shù)與相應(yīng)的行政邊界地圖進行空間關(guān)聯(lián),繪制動態(tài)發(fā)病率地圖,進行空間全局自相性分析(spatial autocorrelation),局部自相關(guān)性分析(Local Indicator of Spatial Association,LISA)和時空聚集性分析(spatial scan statistics)。以上過程由SAS9.2、SPSS16.0、GeoDaTM0.95i、ArcGIS9.3和SaTScan9.1.1軟件實現(xiàn)。 2.收集高發(fā)地區(qū)(遵義市和畢節(jié)市)2002年1月-2011年12月乙腦每月監(jiān)測數(shù)據(jù),在調(diào)整乙腦發(fā)生的自相關(guān)性、季節(jié)性和長期趨勢后,構(gòu)建乙腦的發(fā)生和環(huán)境因素關(guān)系的零膨脹負(fù)二項回歸模型(Zero-inflated negative binomial,ZINB),并且與負(fù)二項回歸模型(negative binomial, NB)、零膨脹Poisson模型(Zero-inflated Poisson, ZIP)進行比較。以上過程由Stata11軟件實現(xiàn)。 3.收集具有詳細家庭地址的乙腦病例個案信息。應(yīng)用地理信息系統(tǒng)(Geographic information system, GIS),將乙腦病例進行空間定位,并與我國氣象因素(平均溫度、最低溫度、最高溫度、相對濕度和降雨量)、海拔、土地利用、歸一化植被指數(shù)、豬密度和人口密度1×1km分辨率的柵格圖像一起構(gòu)建基于最大熵原理(Maximum entropy, ME)的生態(tài)位模型(Ecological Niche Model,ENM),分析環(huán)境變量和乙腦發(fā)生之間的關(guān)系,評估各變量的貢獻百分比,預(yù)測我國乙腦發(fā)生的風(fēng)險。以上過程由MaxEnt3.3.3k和ArcGIS9.3軟件實現(xiàn)。 結(jié)果: 1.2002-2010年我國共報告乙腦病例48,892例,男女性別比為1.57:1;病例以15歲以下的兒童為主,占發(fā)病總數(shù)的87.40%,但近年來成年型乙腦(年齡大于等于40歲)的構(gòu)成比例有上升的趨勢(Cochran-Armitage trend test,Z=9.60,p0.001)。報告發(fā)病率以小年齡組較高,10歲的兒童每組年均發(fā)病率均大于1/10萬。2005-2010年我國共報告乙腦死亡病例1,531例,男女性別比為1.29:1,女性病死率高于男性(5.83%Vs.4.79%, χ2=15.30,p0.001)。以10歲分組發(fā)現(xiàn),乙腦的病死率有隨年齡上升的趨勢(Cochran-Armitage trend test, Z=13.06,p0.001),70歲以上的老人病死率高達14.67%。外籍人士病死率高于我國居民(12%Vs.5.77%,χ2=4.71,p=0.03)。根據(jù)乙腦流行特征(2002年為一個暴發(fā)期,隨后發(fā)病數(shù)迅速下降,2006年又存在一個暴發(fā)期,病例達到峰值,隨后迅速下降,2007-2010年乙腦發(fā)生保持在一個較低的水平上下波動),將2002-2010分為四個時間段:2002,2003-2005,2006,2007-2010進行自相關(guān)和聚集性分析,發(fā)現(xiàn)我國乙腦的發(fā)生存在顯著的空間自相關(guān)性。LISA分析發(fā)現(xiàn)高-高聚集區(qū)主要集中在我國西南地區(qū),同時有向中部擴大的趨勢。選擇最大時間窗口為10%的研究時間,最大的空間窗口為5%的人口數(shù)的橢圓形掃描窗口進行時空聚集性分析,發(fā)現(xiàn)一級聚集區(qū)在我國西南地區(qū)的7月和8月,覆蓋的區(qū)縣數(shù)目逐年增多。各個一級聚集區(qū)呈現(xiàn)較高的發(fā)病率水平(1.79/10萬-3.27/10萬),這些僅占全國3.88%-4.97%人口數(shù)的區(qū)縣有全國同期30.17%-77.59%的乙腦病例。 2.在調(diào)整乙腦發(fā)生的自相關(guān)性、季節(jié)性和長期趨勢后,位于一級聚集區(qū)內(nèi),以中低海拔為主的遵義市和以高海拔為主的畢節(jié)市進行ZINP多因素分析結(jié)果顯示:遵義市乙腦發(fā)生與滯后3月的相對濕度和滯后4月的降雨呈負(fù)相關(guān),其它因素保持不變時,滯后3月的相對濕度每增加1%,乙腦發(fā)生減少5.66%(95%CI:1.67%-9.45%);其它因素保持不變時,滯后4月的降雨量每增加1mm,乙腦發(fā)生減少0.05%(95%CI:0.01%-0.08%);畢節(jié)市乙腦發(fā)生與滯后1月最高溫度呈正相關(guān),其它因素保持不變時,滯后1月的最高溫度每增加1oC,乙腦發(fā)生增加16.47%(95%CI:5.52%-28.55%)。建立的乙腦預(yù)測模型具有較好的擬合和預(yù)測效果,預(yù)測值的殘差均為白噪聲序列,殘差的自相關(guān)和偏自相關(guān)圖也顯示殘差為隨機序列。 3.結(jié)合地理信息技術(shù)和遙感技術(shù),應(yīng)用基于最大熵原理的生態(tài)位模型分析我國乙腦發(fā)生與環(huán)境因素的關(guān)系,并對下一年乙腦發(fā)生進行預(yù)測,結(jié)果顯示:最低溫度貢獻最大(17.94%-38.37%),人口密度、平均溫度和海拔次之,分別是15.47%-21.82%,3.86%-21.22%,12.05%-16.02%;月平均溫度12oC或最低溫度高于-8oC的地區(qū)有乙腦的發(fā)生,月平均降雨量在80-120mm間或NDVI值達到150的地區(qū),乙腦發(fā)生風(fēng)險較高;相對濕度大于65%后,隨著它的增加發(fā)生風(fēng)險也逐漸增加,85%時達到峰值,隨后保持平穩(wěn)或小幅度下降;海拔與乙腦發(fā)生之間呈現(xiàn)負(fù)相關(guān),高海拔地區(qū)乙腦發(fā)生的風(fēng)險較低;土地利用中的灌溉農(nóng)地、雨澆地和建筑用地與乙腦發(fā)生之間有較強的相關(guān)性;乙腦發(fā)生風(fēng)險隨著豬密度和人口密度的增加而增加,當(dāng)分別達到400頭/平方公里和2500人/平方公里時乙腦發(fā)生風(fēng)險保持穩(wěn)定。每個模型的受試者工作特征曲線下面積(the area under the curve,AUC)在0.82-0.91的范圍,假陰性率在5.44-7.42%的范圍,說明模型預(yù)測效果好。模型預(yù)測我國乙腦發(fā)生的高風(fēng)險區(qū)主要在我國西南地區(qū)和中部地區(qū)。利用乙腦發(fā)病數(shù)和模型預(yù)測風(fēng)險進行疊加分析,發(fā)現(xiàn)病例的發(fā)病地點與預(yù)測的風(fēng)險高低一致性很高,病例基本處于中、高風(fēng)險區(qū)域內(nèi)或附近,大多數(shù)的病例(接近60%)發(fā)生在高風(fēng)險地區(qū),而這些地區(qū)僅占了不超過6%的國土面積。 結(jié)論: 本研究描述了我國乙腦流行規(guī)律和分布特征。利用GIS強大的數(shù)據(jù)分析與可視化功能,同時考慮疾病發(fā)生時間和空間屬性的時空掃描技術(shù),首次從區(qū)縣尺度上分析我國乙腦時空分布格局,確定了我國乙腦發(fā)生具有空間自相關(guān)性和高風(fēng)險的一級聚集區(qū)和二級聚集區(qū)。構(gòu)建ZINB,分析高發(fā)區(qū)乙腦的發(fā)生與環(huán)境因素的關(guān)系,定量分析不同地區(qū)的主要影響因素和滯后作用,并進行了短期的時間尺度的預(yù)測。首次構(gòu)建全國范圍內(nèi)高分辨率(1×1km)的空間風(fēng)險預(yù)測模型,探討了影響我國乙腦發(fā)生的主要環(huán)境因素,發(fā)現(xiàn)乙腦發(fā)生的高風(fēng)險地區(qū)和潛在風(fēng)險地區(qū)。研究結(jié)論為我國乙腦的監(jiān)測、蚊媒控制、強化免疫接種等提供科學(xué)依據(jù)。
[Abstract]:Background :
Japanese encephalitis ( JE ) , known as the Japanese encephalitis virus ( JE ) , is an acute central nervous system disease caused by Japanese encephalitis virus ( JEV ) . The encephalitis B is a mosquito - borne infectious disease .
Typical patients were characterized by high fever , conscious disturbance , convulsions , meninges stimulation and other neurological symptoms .
Severe cases may be manifested as respiratory failure or even death . Recent studies by the WHO suggest that more than 24 countries in Asia and the Pacific have a prevalence of encephalitis B , around 67,900 worldwide each year , of which 50 per cent occurred in China .
The incidence of encephalitis B in China has been reduced from 20.92 per 100,000 in 1971 to 0.23 per 100,000 in 2008 .
In recent years , the development of spatial information technology has been widely used in the study of schistosomiasis , malaria , hemorrhagic fever with renal syndrome , tick - borne diseases and other natural epidemic diseases .
Purpose :
To understand the epidemic trend and the changing characteristics of the encephalitis B in China , the paper discusses the relationship between the occurrence of encephalitis B and the environmental factors in China , and identifies the main driving factors and its hysteresis effect . The effects of meteorological , geographical and environmental factors on the development of the encephalitis B in China are analyzed . The spatial difference of the development of the encephalitis B is assessed and the scientific basis for the prevention and control of the encephalitis B in China is provided .
Method :
1 . Collect the monthly monitoring data from January 2002 to December 2010 , and use descriptive epidemiological method to analyze the epidemic characteristics of the occurrence and death of encephalitis B in China ;
spatial correlation of the number of occurrence of district and county with corresponding administrative boundary map is carried out to map dynamic morbidity map , spatial global self - correlation analysis ( spatial correlation ) , local self - correlation analysis ( LISA ) and spatial scan statistics are carried out . The above procedure is implemented by SAS9.2 , SPSS 16.0 , GeoDaTM0.95i , ArcGIS 9.3 and SaTScan9.1 . 1 software .
2 . Collect the monthly monitoring data from Jan . 2002 to December 2011 in the high incidence area . After adjusting the auto - correlation , seasonal and long - term trend of the development of the encephalitis B , the zero - expansion negative binomial regression model ( ZINB ) is constructed and compared with the negative binomial regression model ( NB ) and the zero - expansion Poisson model ( Zero - Expansion Poisson , ZIP ) . The above process is realized by the Stata11 software .
3 . To collect the case information of Japanese encephalitis cases with detailed family address . Using Geographic Information System ( GIS ) , the case of encephalitis B is spatially located , and the ecological niche model ( ENM ) based on Maximum Entropy ( ME ) is constructed along with the meteorological factors ( average temperature , minimum temperature , maximum temperature , relative humidity and rainfall ) , altitude , land use , normalized vegetation index , pig density and population density of 1 脳 1 km . The contribution percentage of each variable is assessed and the risk of the development of Japanese encephalitis is predicted .
Results :
1 . In 2002 - 2010 , 48,892 cases of encephalitis B were reported , and the sex ratio of male and female was 1 . 57 : 1 ;
Cases were dominated by children under the age of 15 , accounting for 87.40 % of the total morbidity , but in recent years , the proportion of adult type B ( > = 40 years ) had a rising trend ( ran ran - Armitage trend test , Z = 9.60 , p0.001 ) . In 2005 - 2010 , 1 , 531 male and female sex ratio was 1 . 29 : 1 , and the mortality of female was higher than that of men ( 5.83 % vs . 4.79 % , 蠂 2 = 15.30 , p0.001 ) . A 10 - year - old group found that the mortality rate of the encephalitis B increased with the age ( ran ran - Armitage trend test , Z = 13.06 , p0.001 ) . The mortality of the elderly over 70 years of age was 14.67 % . The mortality of foreigners was higher than that in our country ( 12 % vs . 5.77 % , 蠂 2 = 4.71 , p = 0.03 ) . In 2002 , 2003 - 2005 , 2006 and 2007 - 2010 , the number of districts and counties covered by the LISA showed a high incidence level ( 1.79 / 100000 - 3.27 / 100000 ) , which accounted for 30.17 % - 77.59 % of the population in the same period .
2 . After adjusting the auto - correlation , seasonal and long - term trend of the development of the encephalitis B , the ZINP multi - factor analysis results show that the relative humidity and the lag of the middle and low altitudes are negative correlated with the rainfall in April and the other factors remain unchanged . When the other factors remain unchanged , the relative humidity after the lag is increased by 1 % , the incidence of encephalitis B is 5.66 % ( 95 % CI : 1.67 % - 9.45 % ) ;
When other factors remained unchanged , the rainfall in April was increased by 1mm and the incidence of encephalitis B decreased by 0.05 % ( 95 % CI : 0.01 % - 0.08 % ) ;
In Bijie City , the highest temperature was positively correlated with the highest temperature in the first month , while the other factors remained unchanged , the highest temperature in January was increased by 16.47 % ( 95 % CI : 5.52 % - 28.55 % ) . The established model has better fit and prediction effect , the residual of prediction value is white noise sequence , the self - correlation and partial autocorrelation of residual are also the random sequence .
3 . Combined with the geographic information technology and remote sensing technology , the relationship between the development of Japanese encephalitis and environmental factors was analyzed by using niche model based on the principle of maximum entropy . The results showed that the minimum temperature contribution ( 17.94 % - 38.37 % ) , population density , average temperature and altitude were 15.47 % - 21.82 % , 3.86 % - 21.22 % , 12.05 % - 16.02 % , respectively .
The average monthly temperature is 12oC or the lowest temperature is higher than -8oC . The average monthly rainfall is between 80 - 120 mm or 150 , and the risk of encephalitis B is higher .
When the relative humidity is greater than 65 % , the risk is increased gradually with the increase of the relative humidity , reaching the peak at 85 % , followed by a smooth or small decrease ;
There was a negative correlation between altitude and the incidence of encephalitis B , and the risk of encephalitis B in high altitude area was lower .
There was a strong correlation between irrigated farmland , rain - irrigated land and building land and encephalitis in land use .
The risk of encephalitis B increases with the increase of the density of pigs and population density . The risk of encephalitis B is stable when 400 heads / km2 and 2500 people per square kilometer are respectively reached . In each model , the area under the curve ( AUC ) ranges from 0.82 to 0.91 , and the false negative rate is in the range of 5.44 - 7.42 % .
Conclusion :
This paper describes the epidemic regularity and distribution of Japanese encephalitis B . Based on the data analysis and visualization functions of GIS , the spatial and temporal distribution pattern of the disease occurrence time and space attribute is analyzed . The relationship between the occurrence of the encephalitis B and the environmental factors is analyzed . The main influencing factors and lagging effects in different regions are analyzed quantitatively .
【學(xué)位授予單位】:中國人民解放軍軍事醫(yī)學(xué)科學(xué)院
【學(xué)位級別】:碩士
【學(xué)位授予年份】:2014
【分類號】:R512.32
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