目的 本研究旨在模拟外来输人性埃博拉出血热(Ebola virus disease,EVD)病例出现后,不同的防控策略对该病在我国传播及爆发流行模式的影响,并为相关决策部门提供一种循证决策依据.方法 选用传染病SIR动力学模型建模.模拟病毒输入区域为我国南方某特大型城市群,该城市群人口5000万,所有人均为易感者.出现输入性病例,模拟情况分别包含单个感染者入境I(0)=1,某小型旅行者团体(全为感染者)入境I(0)=5及I (0)=10.I(0)我们称为“零号感染者”,其发病过程呈现典型的埃博拉出血热发病过程.其传播能力用β表示.对于输入性埃博拉感染者进入我国后,从其发病到得到控制(启动紧急预案)的时间t*设定了如下特征参数:t*=6,12,18,24,30 h.传播模式设定如下:S0=5×108,I0∈[1,20];λ∈(0.1);q∈(0.1];t*∈{6,12,18,24}h.结果 零号感染者输入后,随着应急预案启动的时刻t*变化,病毒暴发曲线为指数型,指数方程为y=1.053e1.801,模型拟合度R2 =1,RSME =0.118 5.如在给定启动应急预案的时间点后(即在同一时间点启动应急预案),零号感染者的数量与被感染者人数上限之间的关系表现为线性增加,线性方程为y=7.605x,模型拟合度R2 =1.以最好模型估计,若零号感染者人数为1,输入后在6h内即被识别并启动应急预案进行处置,则感染人数为7人;若其被隔离时间延长为12,18,24及30 h,则对应的感染人数分别为32、400、1400和8600.以最坏模型估计,若零号感染者人数为10,在6,12,18,24及30 h后才被识别并启动应急预案进行处置,则在对应的新发感染人数分别为67、380、2400、1.4万和8.7万.结论 埃博拉出血热在我国爆发流行的可能性较低,即使出现输入性病例,只要能严格执行国家卫计委的相关规定,该病的传播范围将极为有限.应该加大投入,加强对一线传染科、急诊科和发热门诊医护人员的培训,使之能及时识别该病并加以处置.
目的 本研究旨在模擬外來輸人性埃博拉齣血熱(Ebola virus disease,EVD)病例齣現後,不同的防控策略對該病在我國傳播及爆髮流行模式的影響,併為相關決策部門提供一種循證決策依據.方法 選用傳染病SIR動力學模型建模.模擬病毒輸入區域為我國南方某特大型城市群,該城市群人口5000萬,所有人均為易感者.齣現輸入性病例,模擬情況分彆包含單箇感染者入境I(0)=1,某小型旅行者糰體(全為感染者)入境I(0)=5及I (0)=10.I(0)我們稱為“零號感染者”,其髮病過程呈現典型的埃博拉齣血熱髮病過程.其傳播能力用β錶示.對于輸入性埃博拉感染者進入我國後,從其髮病到得到控製(啟動緊急預案)的時間t*設定瞭如下特徵參數:t*=6,12,18,24,30 h.傳播模式設定如下:S0=5×108,I0∈[1,20];λ∈(0.1);q∈(0.1];t*∈{6,12,18,24}h.結果 零號感染者輸入後,隨著應急預案啟動的時刻t*變化,病毒暴髮麯線為指數型,指數方程為y=1.053e1.801,模型擬閤度R2 =1,RSME =0.118 5.如在給定啟動應急預案的時間點後(即在同一時間點啟動應急預案),零號感染者的數量與被感染者人數上限之間的關繫錶現為線性增加,線性方程為y=7.605x,模型擬閤度R2 =1.以最好模型估計,若零號感染者人數為1,輸入後在6h內即被識彆併啟動應急預案進行處置,則感染人數為7人;若其被隔離時間延長為12,18,24及30 h,則對應的感染人數分彆為32、400、1400和8600.以最壞模型估計,若零號感染者人數為10,在6,12,18,24及30 h後纔被識彆併啟動應急預案進行處置,則在對應的新髮感染人數分彆為67、380、2400、1.4萬和8.7萬.結論 埃博拉齣血熱在我國爆髮流行的可能性較低,即使齣現輸入性病例,隻要能嚴格執行國傢衛計委的相關規定,該病的傳播範圍將極為有限.應該加大投入,加彊對一線傳染科、急診科和髮熱門診醫護人員的培訓,使之能及時識彆該病併加以處置.
목적 본연구지재모의외래수인성애박랍출혈열(Ebola virus disease,EVD)병례출현후,불동적방공책략대해병재아국전파급폭발류행모식적영향,병위상관결책부문제공일충순증결책의거.방법 선용전염병SIR동역학모형건모.모의병독수입구역위아국남방모특대형성시군,해성시군인구5000만,소유인균위역감자.출현수입성병례,모의정황분별포함단개감염자입경I(0)=1,모소형여행자단체(전위감염자)입경I(0)=5급I (0)=10.I(0)아문칭위“령호감염자”,기발병과정정현전형적애박랍출혈열발병과정.기전파능력용β표시.대우수입성애박랍감염자진입아국후,종기발병도득도공제(계동긴급예안)적시간t*설정료여하특정삼수:t*=6,12,18,24,30 h.전파모식설정여하:S0=5×108,I0∈[1,20];λ∈(0.1);q∈(0.1];t*∈{6,12,18,24}h.결과 령호감염자수입후,수착응급예안계동적시각t*변화,병독폭발곡선위지수형,지수방정위y=1.053e1.801,모형의합도R2 =1,RSME =0.118 5.여재급정계동응급예안적시간점후(즉재동일시간점계동응급예안),령호감염자적수량여피감염자인수상한지간적관계표현위선성증가,선성방정위y=7.605x,모형의합도R2 =1.이최호모형고계,약령호감염자인수위1,수입후재6h내즉피식별병계동응급예안진행처치,칙감염인수위7인;약기피격리시간연장위12,18,24급30 h,칙대응적감염인수분별위32、400、1400화8600.이최배모형고계,약령호감염자인수위10,재6,12,18,24급30 h후재피식별병계동응급예안진행처치,칙재대응적신발감염인수분별위67、380、2400、1.4만화8.7만.결론 애박랍출혈열재아국폭발류행적가능성교저,즉사출현수입성병례,지요능엄격집행국가위계위적상관규정,해병적전파범위장겁위유한.응해가대투입,가강대일선전염과、급진과화발열문진의호인원적배훈,사지능급시식별해병병가이처치.
Objective This study presents a computational simulation model to determine the effect of different control strategies on the transmission and outbreak patterns of Ebola virus disease (EVD) in China,in order to provide evidence for policy makers and government authorities.Methods and Materials We selected the SIR dynamics model.We assumed that the EVD patient (s) would enter China at certain urban agglomerations of Southern China.The population in these urban agglomerations is over 50 million and all of them are susceptible to EVD.EVD patient (s) who enter certain ports of these urban agglomerations would be defined as "patient zero" and marked as 1 (0).we set up number of I (0) as:n =1,5,10.β is the transmission capacity of Ebola virus.Given t* the time from occurrence of isolation of EVD patients is t* =6,12,18,24,30 hours.Thus,we have a set of simulation parameters:S0 =5 × 108,I0∈ [1,20]; λ∈ (0,1); q∈ (0,1]; t* ∈ {6,12,18,24} h; Results When patient zero arrives,at the same time t* evolves,the EVD outbreak curve presents as an exponential pattern,the equation is y =1.053e1.801x.Let t* is fixed,then the relation between the numbers of patient zero and the peak of new infections is obeying a linear model,and the equation is y =7.605x.In the best case scenario,the number of patient zero is 1,and is isolated no more than 6 hours after the onset.Under such a circumstance,the new cases who will be infected by the patient zero would only be 7.However,if the isolation time of patient zero is postponed to 12,18,24 and 30 hours,the new cases who will be infected by the patient zero will increase to 32,400,1400 and 8600,respectively.If the number of patient zero is 10,and is isolated after 6,12,18,24 and 30 hours of the onset,then the new cases infected by patient zero would be 67,380,2400,14 000 and 87 000,respectively.Conclusion The possibility of an outbreak of EVD in China is quite low when relevant regulations made by national health authorities are well conducted.It means patient zero and the intimate contact persons should be isolated within 6 hours when patient zero symptoms and signs occur.In addition,we suggest an increased investment in capacity building and precaution equipment for health providers who work in emergency departments,departments of transmission of diseases and fever clinics in hospitals.
