Forty years of the war against Ebola
- R& c, M. k) H- f埃博拉之役四十年
中文概要:
埃博拉病毒疫情自1976年在苏丹南部和旧扎伊尔的埃博拉河地区初次爆发,三年后在苏丹同一地区小规模复发了一次则沉寂了15年。1994年在加蓬地区再次突然复苏,至今在非洲多国已反复爆发15次,造成了4362人感染,2659人死亡。2014年,西非几内亚、利比里亚、尼日利亚和塞拉利昂爆发了历史上最严重和情况最复杂的疫情,局面失控。埃博拉病毒流行无明显的季节性,人群普遍易感且无性别差异,其天然宿主仍不确定。近四十年,疫情在一个地区消散后不知何时会在另一个地区突然暴发,被形容为像光的波粒二象性一般难以理解。由于埃博拉病毒对人体多器官普遍攻击而防范困难,加之开发病毒防治药物项目资金匮乏,人类至今没有找到能有效对抗埃博拉疫情的预防及治疗措施。
Difficulty in identifying infection-related receptors
Rare virus draws little interest from funders
Potential treatments: antibody, interferon, RNA-interference drug, and survivor’s serum
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Original:http://www.zju.edu.cn/jzus
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% f8 ^! A6 {) B( D/ K作者:京虎子 http://wyscipark.lofter.com/post/2f1927_2542671
人类的故乡在中非,那里迄今还有一片很原始的地方。除非坐小型飞机,否则只能乘船才能抵达那些散落的村落,有的地方甚至得坐3周船才能抵达。
1976年9月中旬,扎伊尔北部本巴(Bumba)地区扬布库村的一间小教会医院的医生,报告了几十例相同病例。这些病比疟疾症状严重,包括出血性呕吐、鼻出血、出血性腹泻,其中14位病人死亡,其余病人也危在旦夕。
扎伊尔首都金沙萨收到电报后,扎伊尔卫生部请求国际援助。10月初,该医院被迫关闭。几周后,受扎伊尔卫生部委派,一支国际专家组抵达扬布库村。专家组成员包括来自法国、比利时、加拿大、南非、扎伊尔和美国的专家,来自美国的是CDC的9人团队,因此其领队卡尔•约翰逊就成了专家组的组长。
约翰逊出掌专家组,一不是靠手下人多,二不是靠美国的势力,而是用生命换来的资格。
1962年,正在巴拿马进行研究项目的约翰逊和麦肯齐(Ron MacKenzie)一道前往玻利维亚马格达莱纳(Magdelena),调查当地的一种出血热。他们抵达马格达莱纳后,发现疾病流行情况非常严重,只好暂时返回美国。争取到更多的资助的人手后,他们于次年重返玻利维亚,进行深入的研究。可是没多久,两人也被感染,被送到巴拿马抢救。幸好当地军队医院的医生有在韩战期间治疗流行病出血热的经验,用同样的办法救活了两人。
恢复过来后,两人认为自己已经具备了免疫力,再次来到玻利维亚,并成功地发现了病原。这是一种新型病毒,被命名为马丘坡(MACHUPO)病毒。进一步研究发现,当地的一种小鼠是这种病毒的携带者和传播者,于是通过灭鼠解决了出血热流行。这场流行感染了470人,死亡192人,死亡率40%。病毒消失后,一直到1994年才再次出现,10人感染6人死亡,死亡率60%。
马丘坡病毒是现在已知的烈性病毒之一,能够在空气中存活,可以通过血液和接触感染。但这种病毒对人类的威胁不大,因为其天然宿主Calomys Calosus小鼠生存在玻利维亚丛林深处,由于交通不便形成的一道天然屏障,使得这种烈性病毒不能在人群中扩散。
14年后,回想起在玻利维亚几乎丧命的经历,依然心悸的约翰逊来到了扬布库村。他先将血液样品送CDC等实验室用电镜检查,确定是病毒感染。这种病毒和1967年在西德和南斯拉夫出现的马尔堡(Marburg)病毒相似,马尔堡病毒也引起出血热。那次流行31人发病,7人死亡,死亡率23%。1975年在南非有3人发病,1人死亡。后来时有流行,最严重的一次是2004到2005年在安哥拉的流行,252人感染,227人死亡,死亡率高达90%。
扬布库村发现的病毒因流经本地的埃博拉(Ebola)河被命名为埃博拉病毒,和马尔堡病毒组成新的丝线状病毒科。
在进行紧急处理之后,根据马丘坡病毒的先例,约翰逊认为,下一步是要找到传播源,从而控制流行。埃博拉病毒毫无疑问是一种动物病毒,也毫无疑问是一种能够从动物传染给人的病毒。其源头应该是某种不会得出血热并携带埃博拉病毒的野生动物,很可能还有一种动物作为中间宿主将埃博拉病毒从原宿主带入人群。这种中间宿主应该是一种和人类有接触的动物,而原宿主则是和人类无接触的动物,这样才能解释为什么会突然出现埃博拉病毒流行。
根据这个推论,专家组从扬布库村的动物开始着手调查。他们先在村落里抓了818只臭虫,没有发现携带埃博拉病毒的痕迹;下一个怀疑对象是蚊子,逮了很多蚊子,也没有发现埃博拉病毒,那么就可能是家畜了。他们在村落里抽了10头猪和1头母牛的血,一无所获。也许是鼠类?他们抓了69只耗子、30只大鼠和8只松鼠,也一无所获。只好扩大范围,他们又抓了6只猴子、2头鹿和7只蝙蝠,依旧一无所获,也没有其他动物可以抓了。
此时患病者死亡率已经达到88%,专家组给扎伊尔卫生部提出几条防疫建议,结束了这次行动。离开扬布库村时,专家组有一种预感,埃博拉病毒不会像马丘坡病毒那样重新返回丛林,因为这种凶悍病毒的宿主和传播途径都是未知。
也是在1976年,苏丹西南部也发生了不明原因的传染病流行。WHO派出专家组,从重症病人身上抽血后送英国微生物学研究所,希望那里的实验室能够发现病因。
1976年11月5日,在微生物研究所实验室工作的杰弗里•普莱特(Geoffrey Platt)用注射器将一只感染了苏丹病人血液的豚鼠的肝脏取出来,准备给另外一只豚鼠接种,不小心针头扎到了自己的拇指。
普莱特心里大叫不好,他知道苏丹疫区的病死率已经超过50%,于是赶紧摘下手套,将拇指泡在消毒液中,努力地想挤出几滴血,但挤不出来。他的情绪镇定下来,仔细查看拇指,没有找到伤口。他知道有两种可能,一是没有扎进去,二是伤口很小,已经愈合了。前者是好事,后者则是坏事。普莱特尽力安慰自己,往第一种可能处想,即便是第二种可能,按照其他病毒传播的情况,这么一点点,应该不可能造成感染。
但是,4天后,普莱特病倒了。苏丹的传染源也找到了:埃博拉病毒!
普莱特被送进一间特殊病房,按生物安全3级的标准,房间为负压,医生护士戴口罩。先对他进行干扰素治疗,然后从非洲空运来一位从埃博拉病毒感染中恢复过来的病人的血清,给他注射。
4天后,普莱特的病情加重,呕吐腹泻之外,有免疫系统衰竭的迹象,医生只能给他多用非洲运来的血清。
到第8天,普莱特从鬼门关上回来了。经过很长一段时间的康复后出院,不仅体重下降,而且头发几乎掉光了。得益于及时的治疗,普莱特捡了一条命,也证明了一件事:埃博拉病毒的感染力超强。
(二)苏丹的流行发生在苏丹与扎伊尔边境,离扬布库村500英里,死亡151人,占感染者总数的53%,低于扎伊尔流行的死亡率。其病毒也和扎伊尔的病毒有很大区别,这样就有了埃博拉病毒扎伊尔型和苏丹型。
埃博拉病毒为什么于1976年突然在扎伊尔和苏丹同时流行,而且是两种不同的型?
没有答案。
次年,扎伊尔西南部的一家教会医院收住了一位得出血热的9岁女孩,血样被送到CDC。约翰逊实验室进行培养后,证实是埃博拉病毒。女孩死亡,其感染途径不得而知。
两年后,苏丹流行地再次出现埃博拉病毒流行,22人死亡,死亡率65%,依旧低于扎伊尔型。
之后,埃博拉病毒在非洲消失15年之久。
由于没有解决埃博拉病毒的宿主和传播问题,约翰逊一直希望重返扎伊尔,但苦于没有经费。1979年,他利用WHO在当地进行猴痘研究的机会,再次来到扎伊尔。在本巴地区、扎伊尔北部和喀麦隆东南部,他大规模采取动物样品,一共采集了1500多个动物,包括117种。血、肝、脾、肾样品取出后,冷冻后送CDC。
约翰逊后来在《传染病杂志》发表论文,对这次大规模采样进行总结:一无所获。
埃博拉病毒的来源和传播途径成了约翰逊最大的遗憾。
埃博拉病毒在非洲两地同时流行,传播性强,死亡率极高,使得科学家认为很可能是下一次瘟疫。但流行之后,经过些许余波,埃博拉病毒归隐丛林,让科学家们松了一口气。不过他们不敢放松警惕,继续对扎伊尔、苏丹等地进行埃博拉病毒流行病监测。
十年磨剑,埃博拉病毒在非洲毫无动静。但专家们万万没有想到,埃博拉病毒竟然出现在一个意想不到的地方。
十几年前在一次面试中,得知我的医学背景后,对方脱口而出:你知道几年前机场路抓猴的事吗?
这一问让我借来理查德•普雷斯顿(Richard Preston)的《The Hot Zone》,看完后按图索骥般地实地考察。那是一片和我现在公司所在地极其相似的郊区办公区,离我现在公司所在地不远,离我家也不过10英里之遥。
莱斯顿(Reston),位于维吉尼亚州北部,临杜勒斯国际机场,距美国首都哥伦比亚特区20英里,是美国的IT重镇之一。
1989年,位于莱斯顿的康宁公司下属Hazelton Research Products公司的莱斯顿灵长类检疫中心,来了一批从菲律宾进口用于医学实验的长尾猕猴。到货的时候发现在路上死了两只,这种情况不算什么,类似的动物长途运输常常会导致动物死亡,有时候甚至全军尽没。
猕猴被运到莱斯顿的灵长类检疫中心后继续发生死亡事件,这一下就不正常了。在美国,猴子这种大型的实验动物很贵,运送和检疫人员照顾起来比对自己的孩子还要精心,绝对不会发生虐待的情况。猴子是得病死的,每天死两到三只猴子说明是一种传染病,这引起了中心人员的警惕。经过进一步观察,死亡的猴子有出血热症状,有人突然想到了埃博拉病毒。
这一来就成为美国卫生防疫最大的警报了。陆军传染病研究所闻讯而来,场景如同好莱坞大片,军方将中心剩下的猴子全部杀死,对中心进行全面消毒,房屋被推倒重建。实验室发现确实是埃博拉病毒,但和扎伊尔型、苏丹型有区别;进而发现中心的6位工作人员血液中出现该病毒的抗体,表明已经被感染。根据这些情况,专家认为此型病毒可以通过空气传播。也就是说,这型埃博拉病毒具备流感病毒的传播能力。参照扎伊尔和苏丹的流行情况和死亡率,加上美国首都郊区密集的人口,一场大祸即将临头。
不仅相关人员陷入死亡的恐惧中,整个华府也开始骚动,高层寝食难安:不知道疫情扩散的情况,更不知道一旦出现埃博拉病毒流行,华府地区以至美国会发生什么情况!
山雨欲来风满楼之际,这几位感染者居然一直没有发病,大家把心放回了肚子里。专家前往菲律宾,在马尼拉附近的一家猴出口商处发现大批死于埃博拉病毒感染的猴子,也发现了12名血液中有该病毒抗体的菲律宾人,这12位感染者同样没有任何症状。
于是埃博拉病毒又多了一莱斯顿型,可以感染猴而且死亡率极高,也可以感染人可是不会引起任何症状。
1992年11月,位于西非的科特迪瓦的一家国家公园内的黑猩猩开始死亡。瑞士生物学家克里斯托弗•伯施(Christophe Boesch)在此研究黑猩猩15年了,发现黑猩猩数量减少——一部分黑猩猩死亡,另外一部分不见了。1994年,在解剖一具黑猩猩尸体的时候,一位34岁的瑞士籍女研究生发病,被送进医院按疟疾进行治疗,病情恶化后被运回瑞士。在瑞士,医生们用各种病毒的抗体,包括埃博拉病毒已知三型病毒的抗体进行检测,都查不出病因。最后经过进一步检查,发现了另外一型埃博拉病毒——科特迪瓦型。
这位女科学家幸运地活了下来,体重减轻了十几磅,头发也几乎掉光了,并且成为第一位将埃博拉病毒带出非洲大陆的人。
(三)克威特(Kikwit)是扎伊尔班敦杜(Bandundu)省最大的城市,1995年人口超过20万,尽管如此,这座城市依旧被丛林环绕。
1995年1月6日,基克威特郊外的一位42岁的农民死于出血热。很快,他的三名家庭成员死于出血热。一周后,村里有10个与死者接触过的人死于出血热,其中有人去过城里的妇产医院,导致一名实验室技术员被感染。该技术员被送到基克威特总医院进行治疗,院方认为是伤寒导致的腹部穿孔,对他进行了腹部手术;结果做手术的几名医生和护士都被感染,前来为他祈祷的两位意大利籍修女也被感染,病人和两位修女很快去世。本地卫生部门对此认为是痢疾流行,没有采取任何措施,于是本地几家医院的医护人员和病人相继被感染。
扎伊尔卫生部的一位医生觉得是病毒性出血热,能够导致这么严重出血热的很可能是埃博拉病毒感染。在他的建议下,病人血液样本送到美国CDC,被确定是埃博拉病毒感染。这时已经是5月9日了。整个流行期间,死亡245人,包括60名医护人员。
时隔15年多,埃博拉病毒在扎伊尔再现。尽管确定病因已经太晚,对控制感染流行毫无帮助,但美国CDC还是组织了由CDC、美国陆军传染病研究所专家组成的团队,在扎伊尔专家的陪同下来到基克威特,希望完成约翰逊当年没有完成的任务:找出埃博拉病毒的宿主。为此,专家组还请来一位对啮齿类动物很有研究的丹麦专家。
专家组先来到第一位死者的农场,花了三个月的时间抓了上千只动物,主要是一些小动物和鸟类,在城中则逮了一批蝙蝠。然后将这些动物杀死,取出脾脏和血样,还取出部分肝脏和肾脏;也抽了当地猪、牛和猴子的血。一共采集了3066份血样和2730个脾,送CDC检测。
结果和约翰逊当年一样:一无所获。
埃博拉病毒的来源和传播途径还是一个未解之谜。
埃博拉病毒再一次突然出现,然后又突然地归隐丛林。专家组认为他们错过了埃博拉病毒的流行期,但根据原有的资料和这三个月的研究,对埃博拉病毒的来源提出了三点假设。
埃博拉病毒的原宿主是哺乳动物。
埃博拉病毒流行都和丛林有关,因而其原宿主是一种丛林动物。
这种动物或者是一种稀有动物,或者和人类接触的机会极其罕见。
1996年,俄国国防部下属一家病毒学研究所的一位女研究人员,在从事制备马抗埃博拉病毒时被感染后死亡,成为第一位死于埃博拉的非非洲人,也是第一位因为研究埃博拉病毒而死的研究人员。因为俄国的埃博拉病毒研究有生物战的背景,整个事故的详细情况不得而知。
加蓬与扎伊尔交界处有一个隔绝的小村庄,叫梅依波特2(Mayibout 2),因为在伊温多(Ivindo)河下游1英里处还有一个较大的村庄叫梅依波特。
1996年2月,梅依波特2村里有18人突然同时生病。在生病之前他们一起做了一件事:屠宰了一只黑猩猩,然后饱餐一顿——黑猩猩肉是非洲人饮食结构的一个组成部分——当然黑猩猩也不示弱,会伺机掠走人类小孩然后吃掉。黑猩猩的武力胜于人类,非洲猎人又不屑用现代化武器,于是在狩猎中人类与黑猩猩之间的密切接触甚多;据推测,艾滋病就是这样从黑猩猩传到人类的。
但是,这一次梅依波特2村的村民是不劳而获。村里的几个孩子在丛林中发现了一只死去的黑猩猩,合力把它运回村子。那只猩猩的肚子鼓鼓的,但很久没有敞开肚皮吃肉的村民不在乎,兴高采烈地把它吃了。
18位病人的症状包括发烧、喉咙疼、头疼、呕吐、眼眶出血、肌肉疼,牙龈出血、便血等。一看大事不好,村长下令:送医院!
最近的医院在50英里外的马科库(Makokou)镇,沿河而下要走7个小时。到达马科库后,四名病人在两天内死亡,其中一具尸体被运回梅依波特2号村下葬,还有一位病人逃出医院,挣扎着回到梅依波特2村并死在这里。感染很快蔓延开来,一共31人患病,21人死亡,死亡率为68%。流行期间,由加蓬医生和法国医生组成的专家组来到梅依波特2村,发现流行的是埃博拉病毒。
就这样,黑猩猩走进了埃博拉的盛宴。
黑猩猩是人类最亲的动物,再远还有大猩猩。黑猩猩的数量超过10万,大猩猩的数量不足5万而且一直在下降。梅依波特2村事件之后,在中非进行野生动物研究的科学家们注意到,在野外看到的大猩猩越来越少。到了2002年,常常会见到大猩猩的尸体,其中一些血液呈埃博拉病毒阳性。短短几个月内,一组科学家跟踪的143只大猩猩有90%不见了,不知道是逃离家园还是死于埃博拉病毒感染。科学家们估计,埃博拉病毒至少已经杀死了5000只大猩猩。按这个很保守的估计,埃博拉病毒杀死了超过10%的大猩猩。
如果这场灾难换成人类,将有多少人死亡?
(四)2000年,乌干达加入埃博拉病毒大家庭,在与苏丹交接的北方的古鲁(Gulu)镇出现了苏丹型埃博拉病毒流行。埃博拉病毒从一个村庄传到另外一个村庄,也通过病人从一家医院传到另外一家医院;从北方传到西南方,一共杀死224人,占感染者的53%。非常巧合,这型病毒1976年在苏丹流行的死亡率也是53%。
2001年到2003年,科学家在加蓬和刚果再一次进行大规模调查,希望找到埃博拉病毒的宿主。他们收集了222个不同鸟类的样品、129个小动物样品和679个蝙蝠的样品。这一次用抗体法和PCR法同时检测,在三种蝙蝠样品中发现埃博拉病毒感染的迹象。
这三种蝙蝠都是体型很大的水果蝙蝠,其中最大的一种体型如牛,非洲人将之猎来当食物。16个蝙蝠样品有埃博拉病毒抗体,13个蝙蝠样品有埃博拉病毒基因片段。一共29个样品,在采集的679个蝙蝠样品中只占4%。这些阳性样品中,或者有抗体或者有病毒基因,没有两者兼有的,也没有从蝙蝠体内发现活病毒。因此,虽然这项调查和前几次调查相比,终于获得了有价值的东西,但蝙蝠作为埃博拉病毒宿主的证据还不充分。科学家继续在非洲疫区抓蝙蝠,希望能分离到埃博拉病毒,但始终没有成功。
蝙蝠从一开始就被怀疑,原因之一是非洲的一些蝙蝠体型很大,是非洲人肉食的一部分。原因之二是蝙蝠特别是水果蝙蝠有劣迹。
1999年,马来西亚和新加坡发生尼帕(Nipah)病毒流行,病毒的名字来自第一次检测到病毒流行的村庄。257人感染,100人死亡,死亡率39%;存活者中超过50%留下严重的脑部损伤。
一开始,这场病毒感染流行被认为是日本脑炎(乙脑)病毒引起的,因为得病者都是养猪场的工人,而猪是日本脑炎病毒的扩增体。但其症状使得研究人员认定是一种新型病毒,从而发现了这株病毒。
新病毒病出现,首先怀疑自动物,对尼帕病毒也一样,研究人员马上着手发现其宿主和传播途径。经过多年的研究,搞清了尼帕病毒的前因后果。在尼帕病毒的传播中,猪起到了中间宿主的作用,这是很容易断定的,因为马来西亚的养猪业存栏猪的密度很高,非常容易传播和扩散传染性动物源疾病。而马来西亚养猪业为了效益,在猪厂种了很多芒果树,这样养猪的同时还能收获芒果。对这种安排,猪很高兴,因为常有熟透的芒果从树上掉下来,成为猪的佳肴。另外还有一种动物也很高兴,因为它们也有芒果吃了——这是一种水果蝙蝠,以吃水果为食,学名叫Pteropus。当地人没这么斯文,称之为飞狐。金庸写《雪山飞狐》,不知是否从马来水果蝙蝠处得到灵感?
正是飞狐这种野生动物携带了尼帕病毒,在吃芒果时将病毒通过唾液和尿液留在吃剩的芒果里,这些芒果掉在猪圈里让猪吃了;感染在猪群里扩散,等猪出栏了,尼帕病毒就由猪传播到其他地方。
尼帕病毒在人群中出现,归咎于亚洲饲养业的大力发展。这以后,南亚共发生12起尼帕病毒流行。在孟加拉和印度,主要是因为吃了被病毒感染的水果或水果制品所致,而且出现从人到人的传播,甚至多达半数。
2003年萨斯(SARS)引起轩然大波,其源头最后被指向蝙蝠。近年来出现的新型冠状病毒感染,也是来自蝙蝠。从传染病的角度,蝙蝠成为人类的大敌。
非洲蝙蝠和埃博拉病毒的相关性始终没有得到确定,只证明蝙蝠能够被该病毒感染。近年在亚洲蝙蝠中也发现埃博拉病毒的抗体,在孟加拉进行的研究发现3.5%的蝙蝠有扎伊尔型或莱斯顿型埃博拉病毒抗体,意味着埃博拉病毒可能从非洲到了亚洲。
蝙蝠是埃博拉病毒的原宿主还是中间宿主?蝙蝠能否传播埃博拉病毒?这些问题依然没有答案。埃博拉病毒的来源和传播途径还是一个谜。
2004年,俄国再次出现实验室事故,这一次外界得知了详情。4月5日,中西伯利亚Vektor州立病毒学和生物技术研究中心46岁的研究员Antonina Presnyakova,在进行埃博拉病毒研究时扎伤了自己,很快出现了症状,并于5月19日去世。1988年和1990年两次出现的马尔堡病毒扎伤事故,研究人员一人死亡一人存活。
2007年11月,第五次埃博拉病毒流行出现在乌干达西部。11月5日,乌干达卫生部收到报告,在与刚果交界的山村本迪布焦(Bundibugyo)出现了20例不明死亡。因为死亡者中只有少数有出血症状,一开始并没有怀疑是埃博拉病毒感染。血样送到美国CDC,11月28日CDC回复:这是一种新型埃博拉病毒。这种新型埃博拉病毒就被称为本迪布焦型。这次流行导致116人感染,39人死亡,死亡率34%。除了这次上百名感染者的流行外,还有很多次感染者在百人以下的小规模流行,死亡率从47%到91%。最近的一次是2012年分别发生在乌干达和刚果的小规模流行。
埃博拉病毒并没有归隐丛林。
(五)2007年乌干达西部大流行为埃博拉病毒分型画了一个句号。迄今发现了5型埃博拉病毒,只有莱斯顿型仅感染和致死猴子,能感染人而不出现症状;其余四型对人类都有剧毒,而且能在人与人之间传播,因此被称为第四级病毒,是人类面临的最凶狠的病毒。
埃博拉病毒虽然凶狠,但这四型对人有剧毒的埃博拉病毒均局限在非洲大陆,而且局限在中非和西非。虽然多次流行,但感染者多不过数百人,疫情范围也局限在本地区,因此并没有成为人类迫在眉睫的危机。
但以埃博拉病毒为首的烈性动物病毒一直是人类的心腹之患。人类的烈性传染病的病原最早都是来自动物,是动物携带的微生物进入人类并具备在人与人之间传播能力后形成的瘟疫。从这个角度看,埃博拉病毒已经具备了瘟疫病毒的能力。相比之下,禽流感并不能在人与人之间传播。但是,埃博拉病毒虽然传播能力强,但由于其传播有很强的地域局限性,传播的持续能力也不足,才没有引起大范围的流行。
但是,以菲律宾为源头的莱斯顿型埃博拉病毒则敲响了警钟。按理说,埃博拉病毒都源自非洲,蝙蝠是不可能从中非飞到菲律宾的,究竟是怎么传过去的?其他型埃博拉病毒是否也会通过其他途径传出来,或者被飞机带出中非?一旦出现这种情况,埃博拉病毒传播的局限就有可能被打破,比如出现在大城市里,那样会是什么情况?
因此,必须继续研究埃博拉病毒,特别是搞清其传播途径。但这一点很困难,因为埃博拉病毒一出现往往在几天内就杀死感染者,而且都发生在边远地区,流行也没有什么规律,使得流行病学研究很困难。往往是专家赶到了,流行已经结束了,埃博拉病毒踪迹全无。
目前对埃博拉病毒和马尔堡病毒的疫苗研究一直在进行中,希望有朝一日能研制成功有效的疫苗。
第一种看法认为,埃博拉病毒是一种很古老的病毒,早就在丛林中存在。自1976年以来的历次流行都是偶然事件,是人类由于种种原因接触了埃博拉病毒的感染对象和宿主而导致的。第二种看法则认为埃博拉病毒很可能是一种古老病毒演化出来的新型病毒,自1976年以来的所有流行都是埃博拉病毒逐渐扩散的结果,所有埃博拉病毒都来自1976年扎伊尔流行株。这两种看法都有根据,也都没有确凿的证据。双方的共同点都倾向于蝙蝠是宿主,但并非唯一宿主,可能还有另外一种更古老的动物也是埃博拉病毒的宿主。目前埃博拉病毒主要在大猩猩中流行,对人类的危害还不大。
这两种看法中第二种的可能性最大。因为如果是偶然事件的话,应该一直有埃博拉病毒流行,而不是从1976年才开始。近代在中非并没有出现人类大规模侵袭丛林的迹象,也没有艾滋病毒扩散那种社会生态变化。然而,第二种看法是让人类不寒而栗的,它预示一种死亡过半的烈性传染病正在走出丛林,渐渐地在非洲扩散。终有一日,这种烈性传染病会真正走出丛林、走出非洲,成为下一个瘟疫。
埃博拉病毒是动物源传染病的代表。和禽流感等疾病不一样,埃博拉病毒不是因为人类侵袭动物领地或者大规模进行饲养业造成的,埃博拉病毒等动物病毒来自人类早已走出的丛林,是动物病毒主动出击。
从牛痘苗到磺胺、抗生素,人类陆续征服了很多烈性传染病,导致了人口膨胀、人类平均寿命大幅度提高,文明水平也突飞猛进,让人类认为已经掌握了自己的命运。自从进入农耕社会之后,人类也进入了瘟疫时代,烈性传染病相继出现,甚至常年流行。相比于我们的祖辈,由于微生物学和免疫学的进步,我们所受到的传染病的威胁已经大大地降低了,但并不表明我们已经走出瘟疫时代,艾滋病就是一个典型的例子。埃博拉病毒则预示了另外一种可能:我们快要走出瘟疫时代的幸福时光,很快就要重新进入黑暗。
人类来自非洲丛林,埃博拉病毒也来自非洲丛林,从这一点上来说,它和其他丛林病毒才是真正可怕的。人类之所以走出丛林,就是因为无法征服丛林。黑猩猩、大猩猩之所以没有成为人类,就因为它们没有走出丛林。
既然走出丛林,就只能靠科学的力量去面对丛林中的恶魔。
原文链接:http://www.scipark.net/archives/20386
(题图:肯特•布兰特利感染埃博拉后痊愈出院与医护人员拥抱。)
两位在非洲因为救治埃博拉病人而被传染的美国医护人员,经过精心治疗,最近康复出院。那么,他们是否具备了对埃博拉病毒的免疫能力?
有关专家很谨慎地说,应该具备了对他们所感染的那型埃博拉病毒即最凶狠的扎伊尔型的免疫能力,但是不能打包票。对其他几型埃博拉病毒免疫力的情况尚不得而知。
为什么不验证一下?不敢,因为风险太大,也不道德。
目前这次埃博拉大流行,感染者存活率47%,也就是说,有不到一半的存活机会。那么如何才能成为这47%?
这两位美国人究竟是如何痊愈的,现在很难定论,日后依然很难定论。他们之中一位接受了痊愈者的血清,他们还接受了试验性药物治疗,并且接受了最先进的医疗护理,很难说清是什么原因使他们痊愈的。
埃博拉流行,从一开始耸人听闻的死亡率90%,到现在的53%,说明了一个问题:医疗护理的重要性。尽管没有有效的疗法,但通过高质量的医疗护理,是可以挽救很多甚至大部分患者的生命的。这一点在黄热病、禽流感等烈性传染病上都被反复证明了。以前疫区埃博拉患者死亡率高,是因为疫区的医疗水平很差。目前,全球合作全力以赴地对埃博拉患者进行医疗护理,埃博拉患者的死亡率还会进一步下降。这是国际援助的功劳,是包括中国医生在内的各国医生冒着生命危险奉献的结果。
埃博拉在非洲猖獗的一大原因正是医疗水平低下和卫生状况恶劣,因此两位美国患者极有可能得益于先进的医疗护理。这是患埃博拉后生存指南第一也是最重要的一点。
痊愈者是否具备免疫能力,证据是痊愈者的血清中存在能够中和埃博拉病毒的抗体。在目前的情况下,给予感染者这种血清是一个不得已的办法,但并没有经过任何试验证明其确实有效。迄今为止,还没有痊愈者再次暴露于埃博拉病毒后的任何资料,所以无法确定是否真的具备免疫力,也无法得知这种免疫能力是否能够免疫其他型。
免疫功能在对抗埃博拉上似乎也有一定的效果。埃博拉病毒和艾滋病毒有些相似,感染人体后杀死CD4和CD8淋巴细胞。如果感染者的免疫功能很强,在埃博拉病毒攻击下,如果还能剩下不少CD4和CD8淋巴细胞,患者存活的机会就会更大。反之,如果免疫功能失控,病毒就会释放出炎症分子,使得毛细血管破裂、血压下降、多器官衰竭,以至死亡。
在基因水平也似乎有某种相关性。2007年的一项研究发现,人白细胞抗原B的不同变异与埃博拉病人的存活率有关。有B*(这是乘号×?)07和B*14变异的人感染埃博拉病毒后存活率较高,而有B*15和B*65变异的人感染埃博拉病毒后死亡率较高。
更让人惊喜的是有一种叫NPC1的基因变异在体外实验中能够达到对埃博拉病毒耐受,不会被感染。有这种突变的人细胞不会被埃博拉病毒感染,但并没有做过也不能做人体试验。
这种变异在欧洲人中的比例是1:300~1:400,可以说相当低。但在加拿大新斯科舍居民中达到1:10~1:26。那地方离埃博拉流行区足够远了,这种变异和埃博拉流行的进化筛选没有关联。对于非洲人的NPC1变异情况还没有研究数据。
上面这几点都有很大的风险,一旦不管用没准就有生命危险。埃博拉生存指南最重要的是预防——尽一切可能不被埃博拉病毒感染。
预防上最靠谱的本来是疫苗,但埃博拉疫苗还没有研制成功。其实,对于这种区域性流行的烈性传染病,并不一定要接种疫苗,黄热病就是一个例子。黄热病的死亡率也很高,但只在非洲和美洲部分地区流行,因此即使已有有效的黄热病疫苗,也没有全民接种,只有去疫区才接种。所以,虽然还没有埃博拉疫苗,那么不去疫区就是了。
埃博拉病毒虽然凶猛,但传播能力并不强,专家认为不太可能经过飞机传播。预防埃博拉的卫生措施也比较简单,采取不接触病人体液、不接触灵长类和蝙蝠之类野生动物、勤洗手等措施就可以了。
模型预测埃博拉病毒感染者将持续增多 |
如果病毒按照目前的速度继续传播,Alessandro Vespignani的模型预测,截至9月24日,埃博拉病毒感染者将接近1万人。图片来源:A. VESPIGNANI
美国波士顿市东北大学物理学家Alessandro Vespignani希望他最近的工作将被证明是错误的。7月,Vespignani开始通过建模了解致命病毒埃博拉是如何在西非传播的。根据现有的趋势,患病者和死亡人数将迅速增加,预计将从现有的3000多例和1500人死亡升至约1万个病例(截至9月24日),且之后还会出现更多病例。Vespignani说:“这些数字真的很可怕。”但他强调该模型的假设基于目前的防控措施没有跟进的前提。“我们都希望这个局面不会发生。”
Vespignani并不是唯一一个试图预测埃博拉疫情将如何发展的人。近日,世界卫生组织(WHO)估计,患病人数最终将超过2万人。全世界的科学家正忙于创建计算机模型,以精确描述这一致命病毒的传播。但并不是所有研究者都像Vespignani这样悲观。然而所有的建模者都认为,当前的防控措施不足以遏制这种致命病原体的传播。
英国伦敦维康信托基金会负责人、传染病研究专家Jeremy Farrar表示,在控制疫情暴发方面,计算机模型是非常有用的。它们能帮助类似WHO这样的机构预测所需的医疗物资和人员,以及哪些干预措施将最好地遏制疫情。瑞士伯尔尼大学流行病学家、建模者之一Christian Althaus表示,WHO和撒玛利亚救援会(一家对抗埃博拉病毒的救济组织)都和他取得了联系,希望了解模型的预测结果。
由于缺乏对当前疫情和埃博拉病毒传播方式的了解,建模者也遭遇了困难。例如,科学家已知埃博拉病毒死者的葬礼会传播病毒,但多少人会通过这种方式感染仍是未知数。佛罗里达大学生物统计学家Ira Longini说:“在此之前,我们对埃博拉病毒所知甚少,流行病学的发展还很不完善。”(段歆涔)
《中国科学报》 (2014-09-10 第3版 国际)
Breaking news and analysis from the world of science policy A. VESPIGNANI If spread continues at the current rate, a model by Alessandro Vespignani and colleagues projects close to 10,000 Ebola infections by 24 September. (The shaded area provides the projection's variability range.) Kai is a contributing correspondent forScience O9 g0 e1 J" W, ^ Alessandro Vespignani hopes that4 f! ?$ [2 s- P3 i Vespignani is not the only one trying to predict how the unprecedented outbreak will progress. Last week, the World Health Organization (WHO) estimated that the number of cases could ultimately exceed 20,000. And scientists across the world are scrambling to create computer models that accurately describe the spread of the deadly virus. Not all of them look quite as bleak as Vespignani's. But the modelers all agree that current efforts to control the epidemic are not enough to stop the deadly pathogen in its tracks. Computer models “are incredibly helpful” in curbing an outbreak, says infectious disease researcher Jeremy Farrar, who heads the Wellcome Trust research charity in London. They can help agencies such as WHO predict the medical supplies and personnel they will need—and can indicate which interventions will best stem the outbreak. Mathematical epidemiologist Christian Althaus of the University of Bern,9 I0 x, B% Q( f' t7 A" o But the modelers are hampered by the paucity of data on the current outbreak and lack of knowledge about how Ebola spreads. Funerals of Ebola victims are known to spread the virus, for example—but how many people are infected that way is not known. “Before this we have never had that much Ebola, so the epidemiology was never well developed,” says Ira Longini, a biostatistician at the University of Florida in Gainesville. “We are caught with our pants down.” To a mathematician, combating any outbreak is at its core a fight to reduce one number: Re, the pathogen’s effective reproductive rate, the number of people that an infected person in turn infects on average. An Re0 s3 q5 w0 n" T" [4 B R Outbreak models typically assume that there are four groups of people: those who are susceptible, those who have been infected but are not contagious yet, those who are sick and can transmit the virus, and those who have recovered. A model, in essence, describes the rates at which people move from one group to the next. From those, Re If the disease keeps spreading as it has, most of the modelers/ \& C! @5 r1 _ @1 A3 ~- Z" [ Vespignani has analyzed the likelihood that Ebola will spread to other countries. Using data on millions of air travelers and commuters, as well as mobility patterns based on data from censuses and mobile devices, he has built a model of the world, into which he can introduce Ebola and then run hundreds of thousands of simulations. In general, the chance of further spread beyond West Africa is small, Vespignani says, but the risk grows with the scale of the epidemic. Ghana, the United Kingdom, and the United States are among the countries most likely to have an introduced case, according to the model. (Senegal, which reported its first Ebola case last week, was in his top ten countries, too.) The models are only as good as the data fed to them; up to three-quarters of Ebola cases may go unreported. The modelers are also assuming that key parameters, such as the virus’s incubation time, are the same as in earlier outbreaks. “We might be missing the boat and we have no signal to indicate that,” says Martin Meltzer of the U.S. Centers for Disease Prevention and Control in Atlanta. The biggest uncertainty is how much doctors, nurses, and others can slow the virus. There are many ways of pushing down Re, Farrar says—washing hands, wearing masks, or quarantining people, for example. “But given the complexity of this outbreak and the limited resources, we need to find out what are the two or three things that will most help drive down infections,” Farrar says, and that’s where models can help. For instance, would following up on all the contacts of every case be more effective than following up on the much smaller number who had a certain type of contact with a case, such as sharing a room? Rivers is evaluating interventions, such as increased use of protective equipment or campaigns to isolate infected people. In the most optimistic scenario, every contact of infected people is traced, and transmission in hospitals is reduced by 75%. Even that, while drastically reducing the number of Ebola deaths, did not push Re, _5 g9 U2 h$ o+ h1 d+ Q0 W The challenge varies by country, Althaus says. “In Guinea and Sierra Leone, Re As models get better at differentiating what is happening in places, Rivers says, “you might be able to put firelines around certain communities.” But such measures are very controversial. When Liberia last week barricaded off West Point, a sprawling slum with probably more than 100,000 inhabitants, it drew a largely negative response. “Quarantines and curfews tend to instill fear and distrust towards the whole of the outbreak response including health structures,” a representative for Doctors Without Borders told4 o; C* `0 ?! E3 j; z People in West Africa will have to alter behaviors, Meltzer says. “We won’t stop this outbreak solely by building hospitals. There will have to be a change in the way the community deals with the disease.” Modeling that is easy enough, Vespignani says. “I can decrease the transmission at funerals by 40% easily in a model. That’s one line of code. But in the field that is really hard.” *The Ebola Files: Given the current Ebola outbreak, unprecedented in terms of number of people killed and rapid geographic spread, N: u' J# F( v. W; X http://news.sciencemag.org/health/2014/08/disease-modelers-project-rapidly-rising-toll-ebola
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magazine based in Berlin, Germany.
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his latest work
will turn out to be wrong. In July, the physicist from Northeastern University in Boston started modeling how the deadly Ebola virus may spread in West Africa. Extrapolating existing trends, the number of the sick and dying mounts rapidly from the current toll—more than 3000 cases and 1500 deaths—to about 10,000 cases by 24 September, and hundreds of thousands in the months after that. “The numbers are really scary,” he says—although he stresses that the model assumes control efforts aren't stepped up. "We all hope to see this NOT happening," Vespigani writes in an e-mail.
who is also building Ebola models,
says both WHO and Samaritan's Purse, a relief organization fighting Ebola, have contacted him to learn about his projections.
above 1, and the disease spreads. Below 1, an outbreak will stall.
can be calculated.
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talked to say WHO’s estimate will turn out to be conservative. “If the epidemic in Liberia were to continue in this way until the 1st of December, the cumulative number of cases would exceed 100,000,” Althaus predicts. Such long-term forecasts are error-prone, he acknowledges. But other modelers aren’t much more encouraging. Caitlin Rivers of the Virginia Polytechnic Institute and State University in Blacksburg expects roughly 1000 new cases in Liberia in the next 2 weeks and a similar number in Sierra Leone.
below one.
is close to 1 and the outbreak could be stopped if interventions improve a bit.” In Liberia, Re
has been near 1.5 the whole time. “That means work is only just beginning there.” But Meltzer says there is no reason to believe the situation is any better in Sierra Leone. “We are not seeing any change in the rate of the accumulation of cases,” he says.
Science. Paul Seabright, a researcher at the Toulouse School of Economics in France who has studied such measures, says they are an incentive for people to keep it secret if they have had contact with a patient. Liberia’s harsh actions are “the last thing this epidemic needs,” he says.
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【慧聪制药工业网】这像是灾难电影《极度恐慌》(Outbreak)的现实版,世界上最凶猛的疾病之一,致死率高达90%的埃博拉病毒在西非地区卷土重来。超过1000人因此丧生,被感染者的数字至少有2000人。来自世界卫生组织(WHO)的警告称:报道的病例数和死亡人数大大低估了实际疫情规模……
最令人胆寒的是,人一旦感染这种病毒,没有疫苗注射,也没有其他明显有效的治疗方法。当这种恶性传染病再一次在非洲蔓延,引发谣言和恐慌,全球各国的医疗工作者正与时间赛跑。为何这种上世纪70年代就被发现的病毒至今仍未找到疫苗?在与恶性病毒的短兵相接中,人类怎样才能避免灾难科幻片中的“极度恐慌”成为现实?
疫苗为何仍未面世
当地时间8月15日,总部位于日内瓦的WHO发布声明称,此前民间流传某些产品与实践可预防或治愈埃博拉病毒是谣言,经过完全检测及批准的埃博拉疫苗可能不会在2015年前出现。
对某些声称可预防或治愈埃博拉病毒的产品或方法,WHO予以完全否定,并称其为“盲目疗法”。例如,“摄入大量盐水可预防埃博拉病毒”的谣言已至少导致2名尼日利亚人死亡。
WHO强调,尽管一些有前景的产品正处于研发中,但数十年来的科研工作并未发现任何有疗效或具防护性作用的药剂对人体安全有效。声明称,当前为尽可能挽救埃博拉病患的生命,WHO已认可使用试验性药物治疗。各方正在加速试验性药物生产,但该类药物供应仍然十分有限,而公众也须认识到试验性药物未经人体试验,也未经监管机构批准。
自1976年在非洲的埃博拉河地区发现这种致命病毒的存在,已过去近40年时间,为何经过数十年努力科学家仍未获得能对抗它的疫苗?
在研制病毒疫苗时,传统的做法是采用灭活病毒或者减毒毒株制成,但是对于埃博拉这种烈性病毒,传统的疫苗制法存在显著缺陷。
灭活疫苗是先对病毒或细菌培养,然后用加热或化学剂(通常是福尔马林)将其灭活。要想生产这种疫苗,前提是要得到大量的病毒。由于埃博拉病毒极高的风险,用这种方法制备疫苗的风险同样不言而喻,一旦病毒泄漏便会造成无法挽回的严重后果。目前的实验室研究结果也表明,灭活方法制成的埃博拉疫苗保护效果还不够确切。
同样,减毒疫苗的做法也存在突变恢复毒力的风险,在小鼠和豚鼠中进行埃博拉疫苗试验时就发现过这样的情况,这都使它的安全性无法得到保障。
为了避免这些风险,科学家们开始探索新型疫苗的研发方式。其中病毒载体疫苗是一种前景不错的研发方案。这类疫苗选取一些的其他类型的病毒作为载体,并将其改装重组制成疫苗。如一种名为水泡性口膜炎(VSV)的病毒。研究者对VSV病毒进行了“重组”,将其原有的糖蛋白用埃博拉病毒表面的糖蛋白替换。这样一来,改造之后的疫苗既能让机体产生针对埃博拉病毒的抗体,同时又没有致病性。
但现在这些研究还处于临床前阶段。新型疫苗的“骨架”都来自病毒,虽然经过改造,但仍存在故态复萌的风险,因此监管机构对这类疫苗的应用还比较谨慎。
长期从事埃博拉疫苗的研究的德克萨斯大学微生物与免疫学系的病毒学家托马斯盖斯伯特指出,监管部门对临床试验的审核过程总是格外漫长。根据美国食品和药物管理局(FDA)的新药研发既定流程,新药上市前需要经过总共三期临床试验阶段,前后需要经过至少约6年,数百名患者的参与。
贫穷国家里穷人生的病
事实上,早在1980年代,研究者就已经开始了埃博拉疫苗的试验,但至今仍没有疫苗获得批准上市。这其中最大的障碍不只有技术限制,还有一道巨额研究经费的门槛。
埃博拉病毒被定义为最高等级的四级生物安全病毒。而根据相关规则,只有最高安全等级的P4生物实验室才有资格对疑似埃博拉病毒感染的组织材料进行检测操作与深入研究。此类实验室造价也是最贵的,因此数量很少。
目前即使是在全球范围内,生物安全4级实验室也只有56个,其中还包括一些正在建设中的。其中位于非洲大陆的只有两个。我国唯一的一个P4实验室,位于中科院武汉病毒所。据媒体报道称,目前仍然在积极建造中,尚未竣工。
网上广为流传的一种说法是:“距埃博拉治疗方法面世还有五十来个白人受害者的距离。”这句话听上去十分残酷,但它的确一定程度上反映了事实确实如此。
WHO助理总干事玛丽-保尔肯尼表示:埃博拉是在贫穷国家里穷人生的病,而且相关人数非常少。在欧洲,会针对像基因病这种罕见疾病开发疗法,尽管得这种病的人很少。因为患者或者社会保障体系会买单。但在那些非洲国家,人们没钱,所以无法对企业产生刺激作用。特别是因为开发药物耗资巨大,需要斥资数亿欧元。
盖斯伯特也持类似观点:“主要原因是缺钱”。相对其他常见传染性疾病,埃博拉疫苗的市场很小。不足以刺激大型药企启动疫苗的研发,因此主要还得靠政府资助。然而,人体试验又相当昂贵,需要投入很多钱才行。
试验性药物成救命稻草?
除了疫苗,世界各国的科研人员正在寻求埃博拉病毒的有效的治疗方式。其中备受关注的是由美国马普生物制药公司生产的Zmapp,这一治疗方式不仅在对猴子的测试中取得了好的效果,被认为也对治疗受感染的美国医生肯特布兰特起到了重要作用。
在利比里亚感染埃博拉病毒的布兰特利是在患病9天后才用上Zmapp,当时,他病情已恶化,出现呼吸困难等症状,认定自己肯定“扛不过去”,已向妻子做了最后的道别。但用药一个小时后,布兰特利的病情明显好转,呼吸变得顺畅,身上皮疹渐渐消退,一名医生用“奇迹”形容这一变化。
如今他不仅可以独立行走,还能谈论自己的染病经历。布兰特利的同事使用了两个剂量的ZMapp,症状也显著改善。但这种新药没能挽救同样染病的75岁的西班牙天主教神父米格尔帕哈雷斯的生命。
在此之前,这种新药只在猴子身上做过试验。4只感染了埃博拉病毒的猴子在24小时内注射了Zmapp后得以生还;另外4只染病猴子在48小时内注射了Zmapp,其中两只生还;还有一只作为参照的猴子染病后没有注射Zmapp,结果5天后死亡。
这种药物的原理并不复杂,研究人员从埃博拉病毒中幸存的小鼠体内提取抗体,然后将小鼠抗体进行基因改造后使之成为更适合人类的抗体。
马普公司称:ZMapp在今年1月就进入了治疗埃博拉的候选药物名单,但还在准备进一步扩大动物试验阶段,还从未在人体身上进行过临床试验。
尽管ZMapp的“空降”让人们看到一线希望,但它的库存极少,目前已经全部运抵利比里亚;同时由于缺乏临床试验,其可靠性还有待进一步证明;而且短期内产量难以满足需求。因为生产ZMapp需要让烟草感染经过改造后的抗体,然后让烟草生长大约一周后,才能生产出足够的原料。接下来还要对原料进行纯化,整个过程极为缓慢。雷诺烟草公司发言人称,即使少量生产也需要2个月时间。
除了剂量不足以应对目前的需求,这类试验性药物面临的更大问题是其潜在风险带来的医学伦理担忧。
就是否冒险大规模使用尚未进入临床试验的药物应对当前严重的埃博拉疫情,医学界内部存在不同意见。
对此,利比里亚信息部长布朗表示,他们清楚ZMapp可能带来风险,但如果不这么做,死去的人会更多。
经过审慎的讨论后,WHO医疗伦理委员会12日表示,为抗击西非国家最严重的埃博拉疫情,向埃博拉患者提供试验性药物是符合伦理的。WHO称,使用这种药物时,病人必须“知情并同意,有选择自由、保密、尊重个人意愿、有尊严,并且有社区的参与”。
明年稍早或可广泛应用
美国国家卫生研究院(NIH)8月1日宣布,将在9月启动埃博拉疫苗的临床试验。
NIH过敏及感染性疾病研究所所长安东尼福奇表示,正在推动FDA经由快速通道启动疫苗的I期临床试验。预计2015年1月可以拿到I期试验的结果,之后在开展II期临床试验时,疫区的卫生工作者或许就能用上新研发的疫苗了。
8月9日,WHO称,为阻止埃博拉这一致命病毒的传播,针对埃博拉病毒疫苗的临床试验将加速进行,预计至明年稍早就可广泛应用。
“这一时间表是可行的。”WHO助理总干事肯尼表示。她介绍,目前WHO正与相当数量的研发商接触,以确定是否可以帮助加速整个研发过程。
WHO疫苗与免疫负责人让-马利欧科瓦贝里透露,英国葛兰素史克药厂将于下月开展疫苗的临床试验,并对疫苗上市充满信心。
贝里说:“我们以9月作为展开临床试验的目标时间,首先在美国试验,当然也会在非洲试验,因为病例出现在非洲。考虑到这是一件紧急事件,我们会以紧急程序处理,所以到2015年预计我们就能有疫苗了。”
为争取时间,疫苗的测试可能不会像其他疫苗或药物那样非常严格地进行。肯尼介绍说,只要针对一小部分人的测试结果被证明是有效、安全的,而且在灵长类动物身上的试验数据纪录也良好,那么,疫苗就会被允许上市。
不过,肯尼同时强调,疫苗测试仍需要在严格控制的环境下进行,以确保研究者可以发现可能的不良反应,避免不安全药物的广泛应用,“如果我们盲目前进,到最后我们可能无法知道疫苗是否有效。”
埃博拉20%概率于10月侵入美国 年末全球感染28万9 W% j5 n( E# a: k; y3 n
时间:2014年09月16日 14:24:26 中财网
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美国研究者称,模型显示埃博拉疫情会变糟,9月底侵入英国概率25%,侵入美国概率18%。埃博拉传播速度快于人们对其控制,诸多通往病毒感染国的航线被取消,延误了救援却无法阻止病毒向它国传播。奥巴马称美国会全力以赴对抗埃博拉。
世界卫生组织称,截至8月底,几内亚、利比亚、塞拉利昂共有3685人疑似或确诊感染埃博拉病毒。上周至少有4061人感染,其中2107人死亡。美国东北大学和Fred Hutchinson癌症研究中心研究员称,传染病和流动性模型显示,西非的埃博拉疫情很可能会变糟,预计9月底前疑似或确诊人数是当前的2倍多。9月24日附近,疑似或确诊感染埃博拉病毒的人数可能达到 1万,此后还会有数千人。, D, I: w; y% C5 ~6 d" H. u
埃博拉病毒传染到其它国家只是时间问题。传染病和流动性模型预测,9月底,埃博拉侵入英国的概率为25%,侵入美国的概率为18%。
不过,西方国家出现埃博拉病毒并非最大的威胁。例如在美国,这些病毒可能通过旅行传播到境内。美国对传染病有很好的控制措施,即使有个别人感染,疫情很可能会得到控制。最令人担心的是,当前埃博拉传播速度非常快,超过了人们对其控制。
几位研究人员对埃博拉疫情持悲观态度:
佛罗里达大学生物统计学家Ira Longini认为,埃博拉病毒持续传播,目前看根本停不下来。% P7 q2 h1 b7 L8 C0 F. X
美国东北大学教授Alessandro Vespignani表示,当前非常关键。如果埃博拉感染者数量上升,却无法控制疫情,那时就太迟了,再采取什么措施都很难。世界卫生组织官员们预计,埃博拉病毒感染者总数可达2万人。然而模型显示,实际数量可能会远超过世界卫生组织的预计。Vespignani称,他和同事们每几周就会对模型重新计算,看是否出现了转折。目前看没有,情况依然是非常糟糕。, V8 w3 x9 p/ n* u" _8 n0 s7 V, @
据Wired网站报道,一位教授预计,在最坏的情形下,2014年底埃博拉病毒感染者可能会再增加惊人的27.7万人。
目前医学界尚没有研制出对抗埃博拉病毒的疫苗或治疗措施,只有支持护理。一些病例采用了实验性药物和输血的方式,一个可能有效的疫苗也匆匆进入生产环节。/ s8 L& ?. V. `2 Y3 M5 F! _
专家们认为,应对感染埃博拉病毒的国家给予更多支持,预计至少耗费6亿美元,国际反应加大到当前的3~4倍。目前需要大量医生、护士和其他医护人 员,以及给医务人员的防护装备和生活用品。然而一个问题是,80%通往埃博拉感染国家的航线被取消了,这影响了物资运输,换来的只不过是埃博拉病毒的推迟 传播,代价很大。9 H( Y: t/ e% v( _: C
据彭博新闻社报道,周一,白宫新闻秘书Josh Earnest称,美国总统奥巴马将于明天会见研究人员,美国会全力以赴对抗埃博拉病毒。奥巴马将埃博拉疫情在国家安全中归为“优先级”,不过任务该病毒侵入美国的概率很小。
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The Ebola epidemic in Africa has continued to expand since I$ h8 s" z s8 z0 F
last wrote$ j% N. F w1 |6 t+ R' b, G
about it, and as of a week ago,2 T' ^8 t& O0 J# J
has accounted for
more than 4,200 cases and 2,200 deaths in five countries: Guinea, Liberia, Nigeria, Senegal and Sierra Leone. That is extraordinary: Since the virus was discovered, no Ebola outbreak’s toll has risen above several hundred cases. This now truly is a type of epidemic that the world has never seen before. In light of that, several articles were published recently that are very worth reading.
The most arresting is a$ O$ E1 A2 s* E; X% z% {( H" X; M
piece published last week
in the journal C n5 D4 M0 e' e# T
Eurosurveillance, which is the peer-reviewed publication of the European Centre for Disease Prevention and Control (the EU’s Stockholm-based version of the US CDC). The piece is an attempt to assess mathematically how the epidemic is growing, by using case reports to determine the “reproductive number.” (Note for non-epidemiology geeks: The basic reproductive number — usually shorted to R0
or “R-nought” — expresses how many cases of disease are likely to be caused by any one infected person. An R0
of less than 1 means an outbreak will die out; an R0
of more than 1 means an outbreak can be expected to increase. If you saw the movieContagion, this is what Kate Winslet stood up and wrote on a whiteboard early in the film.)
The
Eurosurveillance, ?7 S" l; _: j9 |' m) Y
paper, by two researchers from the University of Tokyo and Arizona State University, attempts to derive what the reproductive rate has been in Guinea, Liberia and Sierra Leone. (Note for actual epidemiology geeks: The calculation is for the effective reproductive number, pegged to a point in time, hence actually Rt.) They come up with an R of at least 1, and in some cases 2; that is, at certain points, sick persons have caused disease in two others.
You can see how that could quickly get out of hand, and in fact, that is what the researchers predict. Here is their stop-you-in-your-tracks assessment:
In a worst-case hypothetical scenario, should the outbreak continue with recent trends, the case burden could gain2 u( y5 S& F4 i$ Q" R
an additional 77,181 to 277,124 cases1 Y! H/ m. H: O( p. I& Y
by the end of 2014.
That is a jaw-dropping number.
What should we do with information like this? At the end of last week, two public health experts published warnings that we need to act urgently in response.
First, Dr. Richard E. Besser: He is now the chief health editor of ABC News, but earlier was acting director of the US CDC, including during the 2009-10 pandemic of H1N1 flu; so, someone who understands what it takes to stand up a public-health response to an epidemic. In his piece in the2 u1 H$ x( A5 P% D2 g# n: K
Washington Post, “The world yawns as Ebola takes hold in West Africa,” he says bluntly: “I don’t think the world is getting the message.”
He goes on:
The level of response to the Ebola outbreak is totally inadequate. At the CDC, we learned that a military-style response during a major health crisis saves lives…
We need to establish large field hospitals staffed by Americans to treat the sick. We need to implement infection-control practices to save the lives of health-care providers. We need to staff burial teams to curb disease transmission at funerals. We need to implement systems to detect new flare-ups that can be quickly extinguished. A few thousand U.S. troops could provide the support that is so desperately needed.
Aid ought to be provided on humanitarian grounds alone, he argues — but if that isn’t adequate rationale, he adds that aid offered now could protect us in the West from the non-medical effects of Ebola’s continuing to spread: “Epidemics destabilize governments, and many governments in West Africa have a very short history of stability. U.S. aid would improve global security.”
Should we really be concerned about the global effect of this Ebola epidemic? In the4 w4 p; }' l) y7 _$ ]
New York Times, Dr. Michael T. Osterholm of the University of Minnesota* — an epidemiologist and federal advisor famous for) ^% v6 X1 ]1 g0 T
inadvertently predicting. |* N: i! ~( W. o" G* s5 P* |
the 2001 anthrax attacks — says yes, we should. In “What We’re Afraid to Say About Ebola,” he warns: “The Ebola epidemic in West Africa has the potential to alter history as much as any plague has ever done.”
He goes on:
There are two possible future chapters to this story that should keep us up at night.
The first possibility is that the Ebola virus spreads from West Africa to megacities in other regions of the developing world. This outbreak is very different from the 19 that have occurred in Africa over the past 40 years. It is much easier to control Ebola infections in isolated villages. But there has been a 300 percent increase in Africa’s population over the last four decades, much of it in large city slums…
The second possibility is one that virologists are loath to discuss openly but are definitely considering in private: that an Ebola virus could mutate to become transmissible through the air… viruses like Ebola are notoriously sloppy in replicating, meaning the virus entering one person may be genetically different from the virus entering the next. The current Ebola virus’s hyper-evolution is unprecedented; there has been more human-to-human transmission in the past four months than most likely occurred in the last 500 to 1,000 years. Each new infection represents trillions of throws of the genetic dice.
Like Besser, Osterholm says that the speed, size and organization of the response that is needed demands a governmental investment, but he looks beyond the US government alone:
We need someone to take over the position of “command and control.” The United Nations is the only international organization that can direct the immense amount of medical, public health and humanitarian aid that must come from many different countries and nongovernmental groups to smother this epidemic. Thus far it has played at best a collaborating role, and with everyone in charge, no one is in charge.
A Security Council resolution could give the United Nations total responsibility for controlling the outbreak, while respecting West African nations’ sovereignty as much as possible. The United Nations could, for instance, secure aircraft and landing rights…
The United Nations should provide whatever number of beds are needed; the World Health Organization has recommended 1,500, but we may need thousands more. It should also coordinate the recruitment and training around the world of medical and nursing staff, in particular by bringing in local residents who have survived Ebola, and are no longer at risk of infection. Many countries are pledging medical resources, but donations will not result in an effective treatment system if no single group is responsible for coordinating them.
I’ve spent enough time around public health people, in the US and in the field, to understand that they prefer to express themselves conservatively. So when they indulge in apocalyptic language, it is unusual, and notable.
When one of the most senior disease detectives in the US begins talking about “plague,” knowing how emotive that word can be, and another suggests calling out the military, it is time to start paying attention.
*Disclosure: From 2006 to 2010, I worked part-time at the disease news site,CIDRAP, that Osterholm founded. For that matter, I used to be in a book club with Besser, too.
http://www.wired.com/2014/09/r0-ebola/
Mark 16 September 2014 as the day the United States declared an all-out war on the Ebola epidemic raging in West Africa.
As President Barack Obama explained in remarks he made today at the U.S. Centers for Disease Control and Prevention (CDC) in Atlanta, the world is looking to the United States for help. “It’s a responsibility we embrace,” Obama said. “We’re prepared to take leadership on this to provide the kinds of capabilities that only America has, and to mobilize the world in ways that only America can do. That’s what we’re doing as we speak.”
At the same time Obama was speaking in Atlanta, the U.S. Senate held an Ebola' K# j. D' ?+ D
hearing! J1 H' r/ e! \; O* |; }% x
that featured testimony from leading public health officials and perhaps the world’s most famous Ebola survivor, Kent Brantly, who became ill with the disease while treating patients in Liberia in July. “We must take the deadly dangerous threat of the Ebola epidemic as seriously as we take ISIS [Islamic State in Iraq and Syria],” said Senator Lamar Alexander (R–TN).
The centerpiece of what Obama called “a major increase in our response” indeed is the U.S. military, which in cooperation with the Liberian government will set up a command center in Monrovia led by U.S. Army Maj. Gen. Darryl Williams. As Obama explained, the military will set up a command and control, logistics and engineering to support civilian organizations working in the region. “Our Armed Services are better at that than any organization on Earth,” Obama said.
The U.S. response will focus on providing beds for Ebola patients—which are almost nonexistent in Liberia—isolation spaces to hold people when Ebola Treatment Units have no space, more trained health care workers, an air bridge to move people and materiel into West Africa more quickly, and kits to help families with infected people in the house both care for an ailing person and protect themselves from infection. “We can’t dawdle on this one,” said Obama, who urged the global communities to dramatically step up their response, too. “International organizations just have to move faster than they have up until this point.” (This fact sheet
explains the details of the revamped U.S. response.)
At the 3-hour-long Senate hearing—which, in an unusual move, was jointly held by an appropriations subcommittee and the Committee on Health, Education, Labor and Pensions—topics ranged from financing the effort to the need for a greater sense of urgency, public health and scientific issues, and personal experiences. Beth Bell, who directs CDC’s National Center for Emerging and Zoonotic Infectious Diseases, described the epidemic in Liberia, Sierra Leone, and Guinea as “ferocious and spreading exponentially,” so severely crippling the health care systems in some locales that malaria can’t be treated and infants cannot safely be delivered.
Today’s5 T. I- Q+ r7 d- [
situation report' g7 y$ T. l, y! b% o: S( t
from the World Health Organization estimates that there have been nearly 5000 cases, nearly half of whom have died, but Bell says CDC believes “actual numbers would be two to three times higher.” She stressed that we have the tools to stop this epidemic but that the window of opportunity is closing. “If we do not act now to stop Ebola we could be dealing with it for years to come affecting larger areas of Africa,” she said.
Senators repeatedly asked Anthony Fauci, head of the U.S. National Institute of Allergy and Infectious Diseases, whether the Ebola virus might mutate into a more dangerous form and even spread through the air. “We’re watching that carefully,” Fauci said. He explained that like all RNA viruses, the one that causes Ebola makes a lot of mistakes when it copies itself, but most of these mutations do nothing. “It is an unusual situation where a mutation will completely change the way that a virus is transmitted,” said Fauci, stressing that it was not impossible but highly unlikely. “What is likely is if we don’t do what we’re doing now, in the sense of a major ramping up of infection control capability, including what we’re hearing about getting the military heavily involved with all of the things they bring to the table … it’s going to get worse and worse,” Fauci said. “A virus that doesn’t replicate can’t mutate.”
The U.S. Department of Defense is hoping to reprogram $500 million to Ebola efforts. The Obama administration has asked Congress to pass a continuing resolution that will give $30 million more dollars to CDC to use through 11 December, and $58 million to the Department of Health and Human Services to support development of experimental vaccines and treatments. The continuing resolution has passed the House of Representatives, and Senator Tom Harkin (D–IA), who chaired the joint committee hearing, said he expects the Senate to pass it “in the next day or two.” But Harkin and others stressed that more money will be need for the fiscal year 2015 budget. “I hate to say this but Ebola will not be conquered in the 10 weeks of the continuing resolution.”
Harkin and other senators expressed surprise at the lack of a clear leader for the overall U.S. effort against Ebola. “I’m kind of startled to find that out,” Harkin said. Senator Barbara Mikulski (D–MD) said this was an issue the Senate needed to take up with Obama. “We need a point person,” Mikulski said. “If we wanted to meet with: V% G0 @& w8 ?& @# B$ L
the
person in charge, who would be
theperson in charge?”
The hearing ended with testimony and questions of Brantly, an American doctor with Samaritan’s Purse who was airlifted from Monrovia to Atlanta for state-of-the-art care and is doing well today. Brantly, who met with Obama in the Oval Office this morning, spoke of the many people he treated who died of Ebola and the urgent need for healthcare workers from other countries to go help in West Africa.
“Many, including one of the senators today, used the analogy of a fire burning out of control to describe this unprecedented Ebola outbreak,” Brantly said. “Indeed it is a fire. It is a fire straight from the pit of hell. We cannot fool ourselves into thinking that the vast moat of the Atlantic Ocean will protect us from the flames of this fire. Instead we must move quickly and immediately to deliver the promises that have been made and to be open to practical, innovative interventions. This is the only way to keep entire nations from being reduced to ashes.”
*The Ebola Files: Given the current Ebola outbreak, unprecedented in terms of number of people killed and rapid geographic spread,
Science2 N) w" n2 }+ ?. E: X8 v
and
Science Translational Medicine% q \: e5 s+ C) O) }* M! F/ s
have made
a collection of research and news articles on the viral disease
freely available
to researchers and the general public.
http://news.sciencemag.org/africa/2014/09/u-s-declares-war-ebola-epidemic
As many as 500,000 people could be infected with Ebola virus disease by the end of January, according to the U.S.
Centers for Disease Control and Prevention5 R& k+ E- e1 _; O2 ?
in Atlanta. The CDC estimate, due to be released this week, is based on “dynamic modeling” and assumes no additional aid to help battle the disease, a person familiar with the report told
the Washington Post.
Infectious-disease experts, aid workers and global health advocates said the number of Ebola cases is increasing much more rapidly than the World Health Organization, or WHO, had projected, especially in Guinea, Liberia and Sierra Leone, collectively the West African epicenter of the outbreak., |" B; E1 F7 ]
Villagers are complicating containment/ f6 q2 u" {5 G# U4 k
efforts with police reporting health-care workers in Sierra Leone coming under attack while trying to bury victims.
United Nations officials say now that the outbreak has moved from rural to urban areas, the number of cases is doubling in about three weeks. Ebola is spread person-to-person through bodily fluids.
“One of the scary things about this outbreak is that all the general models of the past have been broken,” John Connor, associate professor of microbiology at Boston University School of Medicine and investigator at the university’s National Emerging Infectious Diseases Laboratories, told the Post. “I’m really worried that no one has a handle on everything that’s happened. Do we know all the places where there’s been virus present?”
WHO estimates
at least 5,357 people have been infected so far, 2,630 of whom have died, but officials say those numbers largely underestimate the problem. The disease has been detected in Nigeria and Senegal, as well as the hardest-hit countries. Laurie Garrett of the Council on Foreign Relations estimates there probably will be 250,000 cases by Christmas without intervention.
U.S. President Barack Obama last week O8 M& \7 [! D1 a
announced plans3 n$ o4 Q' x/ k0 U5 E4 |
to send U.S. troops to West Africa and commit as much as $1 billion to fight Ebola, calling the disease a serious security threat.
http://www.ibtimes.com/ebola-outbreak-cdc-estimates-many-500000-ebola-cases-end-january-1692525
* s$ l; e4 c- a" c6 \, v2 XU.S. SCIENTISTS SEE LONG FIGHT AGAINST EBOLA
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The deadly
Ebola
outbreak sweeping across three countries in West Africa is likely to last 12 to 18 months more, much longer than anticipated, and could infect hundreds of thousands of people before it is brought under control, say scientists mapping its spread for the federal government.
“We hope we’re wrong,” said Bryan Lewis, an epidemiologist at the Virginia Bioinformatics Institute at Virginia Tech.
Both the time the model says it will take to control the epidemic and the number of cases it forecasts far exceed estimates by the
World Health Organization, which said last month that it hoped to control the outbreak within nine months and predicted 20,000 total cases by that time. The organization is sticking by its estimates, a W.H.O. spokesman said Friday.
But researchers at various universities say that at the virus’s present rate of growth, there could easily be close to 20,000 cases in one month, not in nine. Some of the United States’ leading epidemiologists, with long experience in tracking diseases such as influenza, have been creating computer models of the Ebola epidemic at the request of the National Institutes of Health and the Defense Department.
The
Centers for Disease Control and Prevention) |8 ]6 U$ G# z/ s' S
declined to comment on the projections. A spokesman, Tom Skinner, said the agency was doing its own modeling and hoped to publish the results soon. But the C.D.C. director, Dr. Thomas R. Frieden, has warned repeatedly that the epidemic is worsening, and on Sept. 2 described it as “spiraling out of control.”
While previous outbreaks have been largely confined to rural areas, the current epidemic, the largest ever, has reached densely populated, impoverished cities — including Monrovia, the capital of
Liberia
— gravely complicating efforts to control the spread of the disease.
Alessandro Vespignani, a professor ofcomputational sciences/ |, m$ U, g4 ]' v! w9 {
at Northeastern University who has been involved in the computer modeling of Ebola’s spread, said that if the case count reaches hundreds of thousands, “there will be little we can do.”
What worries public health officials most is that the epidemic has begun to grow exponentially in Liberia. In the most recent week reported, Liberia had nearly 400 new cases, almost double the number reported the week before. Another grave concern, the W.H.O. said, is “evidence of substantial underreporting of cases and deaths.” The organization reported on Friday that the number of Ebola cases as of Sept. 7 was 4,366, including 2,218 deaths.
“There has been no indication of any downturn in the epidemic in the three countries that have widespread and intense transmission,” it said, referring toGuinea, Liberia and
Sierra Leone.
The scientists who produced the models cautioned that their dire predictions were based on the virus’s current uncontrolled spread and said the picture could improve if public health efforts started to work. Because conditions could change, for better or for worse, the researchers also warned that their forecasts became shakier the farther into the future they went.
Dr. Lewis, the Virginia Tech epidemiologist, said that a group of scientists collaborating on Ebola modeling as part of an N.I.H.-sponsored project called Midas, short for
Models of Infectious Disease Agent Study, had come to a consensus on the projected 12- to 18-month duration and very high case count.
Another Midas participant, Jeffrey L. Shaman, an associate professor of environmental health sciences at the Columbia University Mailman School of Public Health, agreed.
“Ebola has a simple trajectory because it’s growing exponentially,” Dr. Shaman said.
Lone Simonsen, a research professor of global health at George Washington University who was not involved in the modeling, said the W.H.O. estimates seemed conservative and the higher projections more reasonable.
“The final death toll may be far higher than any of those estimates unless an effective vaccine or therapy becomes available on a large scale or many more hospital beds are supplied,” she said in an email.
Dr. Vespignani! x, f5 l" R' a0 o
said that the W.H.O. figures would be reasonable if there were an effective campaign to stop the epidemic now, but that there is not.
The modeling estimates are based on the observed growth rate of cases and on factors like how many people each patient infects. The researchers use the past data to make projections. They can test their methods by, for instance, taking the figures from June, plugging them into the model to predict the number of cases in July, and then comparing the results with what actually happened in July.
Dr. Shaman’s research team- r4 k% H! Z/ \9 x& y
created a model
that estimated the number of cases through Oct. 12, with different predictions based on whether control of the epidemic stays about the same, improves or gets worse. If control stays the same, according to the model, the case count by Oct. 12 will be 18,406. If control improves, it will be 7,861. If control worsens, it will soar to 54,895.
Before this epidemic,
the largest Ebola outbreak/ O0 j4 j: h/ k6 t( I3 W) c1 Q& I
was in Uganda from 2000 to 2001, and it involved only 425 cases. Scientists say the current epidemic surged out of control because it began near the borders of three countries where people traveled a lot, and they carried the disease to densely populated city slums. In addition, the weak health systems in these poor countries were not equipped to handle the disease, and much of the international response has been slow and disorganized.
But questions have also been raised about whether there could be something different about this strain of Ebola that makes it more contagious than previous ones.
Researchers are doubtful, but Thomas W. Geisbert, an Ebola expert at the University of Texas Medical Branch in Galveston, said it was important to keep an open mind about the possibility. During vaccine tests expected to start next month in monkeys, he said, he and his colleagues will monitor infected animals to see if they develop unusually high virus levels early in the disease that might amplify its infectiousness.
Some scientists have also suggested that as the outbreak continues and the virus spreads from person to person, it will have more opportunities to mutate and perhaps become even more dangerous or contagious. But Stuart T. Nichol, chief of the C.D.C.’s Viral Special Pathogens Branch, said that so far, researchers monitoring the mutations had seen no such changes.
Article from
New York Times
美国疾控中心:埃博拉患者或将增至140万
利比里亚闹埃博拉病毒“僵尸”丑闻 全球致三千人死作者: 2014年09月29日 来源:中化新网
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当地民众指政府未有提供足够协助对抗埃博拉。
中化新网讯 综合媒体报道,世界卫生组织发布最新疫情通报说,仍在西非肆虐的 埃博拉疫情已经导致超过3000人死亡。世卫同时警告疫情还在持续扩散。
埃博拉疫情失控的利比里亚,近日竟传出有两名埃博拉死者离奇”复活“,令民众陷恐慌。有迷信的民众更认定,这两名“埃博拉病毒僵尸”是不应存在世上的鬼魂。外界则认为,闹出埃博拉死者“死而复生”的荒谬情况,是因当地医生误判两人已死所致,更估计有很多埃博拉病人未死已被埋。
当地媒体报道,两名“复活”的女死者是40多岁的夸伊(Dorris Quoi)和60多岁的凯贝(Ma Kebeh),分别来自东北部宁巴州两个小区。两人被指已死,在被送往埋葬期间突然“复活”,吓煞民众。其中凯贝在被判定死亡后两天,一直被关在室内,不曾进食亦没接受药物治疗,令“复活”之事更显不可思议,引起民众恐慌。惟报道未提及两人“复活”后的健康状况。
宁巴州近日已屡屡传出奇怪的埃博拉消息,包括一名当地医生声称可治愈埃博拉,但讽刺地,上周他已因感染埃博拉病毒身亡。
不少评论都认为,今次闹出“僵尸”疑云是因医生误判患者身亡,更揭示当地应对埃博拉疫情的资源严重不足。有网民更反讽,利比里亚的埃博拉死亡数字高企,当中可能有不少人,是因医生误判而活活被埋。
利比里亚的埃博拉疫情在西非疫国中属最严重,死亡个案占总数4成,惟对抗疫情的资源却严重不足。其中西南部博米州仅得两名医生,除照顾埃博拉患者,更需处理日常病人。医生之一洛根(Gobee Logan)称,他们几乎需照顾8万5千名病人。世卫则于周五表示,英国葛兰素史克及美国NewLink药厂的数千剂伊波拉试验疫苗,最快可望明年初送到疫国使用。
: G, n! S' {/ c4 E" @5 _$ @0 E医生用艾滋病药治活埃博拉病患 13人获救
在杜伯曼堡的一家隔离中心,医生洛根让诊所内的埃博拉感染者服用了治疗艾滋病的药物拉米夫定,结果15人中13人生还,死亡率从原来的70%下降至7%。据了解,生还病人在感染后的5天内服用了拉米夫定。(新闻晨报 (微博))
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Ebola Breakthrough?
bywilderness voice
"My stomach was hurting; I was feeling weak; I was vomiting," Elizabeth Kundu, 23, says of her bout with the virus. "They gave me medicine, and I'm feeling fine. We take it, and we can eat -- we're feeling fine in our bodies." Kundu and the other 12 patients who took the lamivudine and survived, received the drug in the first five days or so of their illness. The two patients who died received it between days five and eight.) D2 c* H0 T! M3 iLamivudine is a nucleoside analog:; ]3 w- V6 q7 G2 U+ ~6 x/ \
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[Dr. Logan] also knows American researchers will say only a real study can prove effectiveness. ..."Our people are dying and you're taking about studies?" he said. "It's a matter of doing all that I can do as a doctor to save some people's lives."$ r/ j% ~. e0 i
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Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases says that theoretically, Logan's approach has some merit.... other drugs in this class are being studied to treat Ebola
These agents can be used against hepatitis B virus, hepatitis C virus, herpes simplex, and HIV. Once they are phosphorylated, they work as antimetabolites by being similar enough to nucleotides to be incorporated into growing DNA strands; but they act as chain terminators and stop viral DNA Polymerase. They are not specific to viral DNA and also affect mitochondrial DNA. Because of this they have side effects such as bone marrow suppression.Ebola virus uses RNA only and does not create any DNA. However, RNA requires nucleotides for its assembly just as does DNA, so it stands to reason it could work for Ebola as well as HIV. In any case, it seems to be working, since the chance of this large a proportion of patients surviving otherwise, without treatment, would be quite unlikely. # ~9 R; D4 E# \ I& B
[color=rgb(255, 0, 0) !important]Dr
Gobee Logan gave the [color=rgb(255, 0, 0) !important]drug lamivudine to 15 Ebola patients in a clinic in Tubmanburg, and 13 survived.This gives patients treated with [color=rgb(255, 0, 0) !important]lamivudine
a 7% mortality rate, whereas overall mortality rates for those infected are 70%."My stomach was [color=rgb(255, 0, 0) !important]hurting; I was feeling weak; I was [color=rgb(255, 0, 0) !important]vomiting," Ebola patient Elizabeth Kundu, 23, told CNN. "They gave me medicine, and I'm feeling fine. We take it, and we can eat – we're feeling fine in our bodies."
Those patients who survived after taking lamivudine, took the medication during the first five days of infection. The two who died started treatment five and eight days after onset of the illness.
"I'm sure that when [patients] present early, this medicine can help," Logan said. "I've proven it right in my center."
Logan said that he was aware that the medical establishment would remain sceptical until[color=rgb(255, 0, 0) !important]research had been undertaken involving a much larger group of patients, half of whom would be given lamivudine, and the other half a placebo.
"Our people are dying and you're taking about studies?" he said. "It's a matter of doing all that I can do as a doctor to save some people's lives."
He said that he decided to try using lamivudine after reading in a medical journal that HIV and Ebola replicates in the body in similar ways.
Initially Logan tried the drug on a colleague who had become infected, and within two days he showed signs of improvement and survived.
Researchers at the National Institute of Allergy and Infectious Diseases told CNN that they would be willing to carry out follow-up tests.
The World Health Organisation said that [color=rgb(255, 0, 0) !important]experimental use of two trial Ebola [color=rgb(255, 0, 0) !important]vaccinesdeveloped by GlaxoSmithKline and NewLink has begun.
非洲以外第一例 美确诊本土首例埃博拉感染病例(1)
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中新社休斯敦9月30日电(记者 王欢)美国疾病控制和预防中心(CDC)30日宣布,美国得克萨斯州达拉斯市一位成年男性病患被确诊带有致命埃博拉病毒,这是美国本土发现的首例埃博拉感染病例,也是非洲以外确诊的第一例。目前,该患者病情危重,在医院被“严格隔离”。
此前,美国已经5次把感染埃博拉病毒的援非人员接回国治疗,其中已有人康复出院。但美国本土发现的该例埃博拉病例有所不同,人们担心其可能已经在人群中造成传染。
美国疾控中心30日确认,该病人的初步测试结果为埃博拉病毒阳性。这是首例在美国本土确认的埃博拉病例,也是非洲以外的第一例。
疾控中心主任弗里登(Thomas Frieden)在30日的发布会上表示,该患者从利比亚到美国达拉斯探亲,他于9月19日离开利比亚,9月20日抵达得克萨斯州,当时没有任何症状。
数日后,这位病人表现出了埃博拉症状,于上周末住进位于达拉斯的得州卫生长老会医院。
医院遵守CDC的建议,对该病患实施严格的隔离,以保证医护人员和患者的安全。这位病患不愿透露姓名,院方也没有公布其国籍。
该院流行病学家古德曼(Edward Goodman)30日指出,埃博拉病毒不会通过空气传播,在医院里的其他患者和工作人员没有任何风险。他补充说,“西非没有足够的隔离装备和自来水,而我们没有这些问题,完全有能力照顾这位病人,并确保其他人的安全。医院目前继续正常运转。”
达拉斯卫生和人类服务部门主任汤普森(Zachary Thompson)表示,“疾控中心将派遣健康专家部署到达拉斯,我们完全有信心防止其传播。”
“人们没有理由对此担心。”休斯敦贝勒医学院热带国家医学院院长霍特兹(Peter Hotez)表示,“埃博拉病毒不会轻易地在人与人之间传播,我们在控制和跟踪病毒方面有非常出色的基础设施,因此美国不会出现埃博拉疫情。”
世界卫生组织27日发布最新疫情通报说,在西非肆虐的埃博拉疫情已经蔓延至5个国家,导致至少3091人死亡。世卫同时警告,若未有控制疫病的明显进展,埃博拉疫情还将持续扩散。
核心提示:该患者从利比亚到美国达拉斯探亲,他于9月19日离开利比亚,9月20日抵达得克萨斯州,当时没有任何症状。
9月24日,在利比里亚首都蒙罗维亚,利比里亚总统翰逊-瑟利夫(中)、代理外交部长格里斯比(右)和中国驻利比里亚大使张越(左)出席中国向利比里亚提供抗击埃博拉疫情新援助换文签字仪式。约翰逊-瑟利夫在当日致辞中高度赞赏中国新一轮抗疫援助。她说,这再次证明中国一直是利比里亚和非洲的真心朋友和可靠伙伴。在当前利抗疫急需财政和物资援助时,中方再次提供了大额援助,对利比里亚抗疫是个巨大的帮助,对利比里亚的经济恢复和重建也将起到重要作用。新华社发(高斌摄)
4 D! t. j: s! a4 i# H, J' ?. ]延伸阅读埃博拉发现者:早期研究设备简陋 庆幸未被感染
当地时间9月22日,尼日利亚和塞内加尔两国为预防埃博拉病毒蔓延,对在校的学生进行体温监控和日常卫生管理。
中新网9月29日电 40年前,比利时安特卫普一名年轻的科学家彼得·皮奥特所在的团队发现了埃博拉病毒,德国《明镜周刊》近日对皮奥特进行了专访,皮奥特向记者谈及了当初埃博拉病毒是如何被发现,以及为何此轮埃博拉病毒会如此严重等话题。
1976年9月,比利时航空公司一名飞行员给研究团队带来了一位扎伊尔共和国(今刚果民主共和国)的医生托来的血液样本,同时还有一封信件。这名医生在信中表示,血液样本来自一名当地村庄患病的比利时修女,医生请求研究人员确定该修女是否患了黄热病。
皮奥特表示,他们团队完全不知道这种病毒的危险性,当时的实验室没有现在这么安全,研究人员只穿着了普通实验室外衣和手套就开始了工作。
在毫无戒备的情况下,研究就这么进行着。研究者们排除了黄热病、拉沙热和伤寒后陷入了困境,他们随后将病毒从血样中分离出来,注入老鼠的体内。而在数天后,老鼠一个个接连死去,他们最终认定,这种病毒具有高致命性。
实验的过程惊险而又紧张。研究人员好几次沾到了受病毒感染的血液,但好在没有发生任何事。而在电子显微镜的帮助下,研究者们破译了病毒的图像,并惊讶于从来没有见过这种病毒。这种病毒与黄热病没有共同点,反倒与一种1960年代在德国肆虐的马尔堡病毒相似。
在美国研究者的帮助下,他们确认这种新发现的病毒不是马尔堡病毒。皮奥特最终因为新发现的病毒,成为第一批前往扎伊尔的研究人员。
皮奥特表示,由于对病毒一无所知,他们在非洲时也面临着恐惧、害怕等负面情绪。而看到真正受埃博拉病毒感染者的样子,他还是感到了震惊。
皮奥特指出他在非洲看到许多医务人员对处理血液的不严谨而受到感染,当年他曾警告这些人不要用未经消毒的针头来注射,而对于本次在西非爆发的埃博拉疫情,不幸的是医院再一次成为了早期疫情爆发的源头。
皮奥特表示,本轮埃博拉疫情暴发有多方面的原因,专业人员缺乏、地区人口流动性大、政局动荡等都造成了不利的影响。而在疫情肆虐了数个月后,人们才意识到事态的严重性。皮奥特说,西非的埃博拉疫情绝不是地区疾病,如果不及时介入,或蔓延至全球。
微信搜索关注公众号“参考消息”(ID:ckxxwx),外国媒体每日报道精选,随时随地想看就看,还有会员福利等着您哦。
延伸阅读外媒:西非五国埃博拉疫情已夺3000多人性命
参考消息网9月29日报道
外媒称,世界卫生组织说,目前在西非五个国家肆虐的埃博拉疫情至今已夺走了超过3000人的性命;该组织同时警告,疫情还在持续扩散。
据联合早报网站9月29日报道,世卫组织周末公布的最新数据显示,这场全球历来最严重的埃博拉疫情至今已有6574人染病,其中3091人已经病逝。该组织上周四说,截至9月21日,全球的埃博拉病例共有6263起,死亡病例为2971起。
据了解,利比里亚仍是疫情最严重的国家。该国目前已出现1830起死亡病例。
世卫警告,埃博拉疫情仍在继续扩散;在利比里亚靠近科特迪瓦的边境地区,最近报告了6例埃博拉确诊病例,而在此之前该地区一直没有埃博拉病毒传播。几内亚也有新的地区发现病例。
世卫组织助理总干事基尼说,该组织正与各方加快埃博拉疫苗临床试验,相关疫苗或将于明年1月限量分配使用。
更多“西非”,微信搜索关注公众号“参考消息”(ID:ckxxwx),外国媒体每日报道精选,随时随地想看就看,还有会员福利等着您哦。
延伸阅读英媒:埃博拉破坏西非生活方式 握手亲吻受限制
当局建议人们不要握手。
超市里的收款员也带上手套。
中新网9月25日电 据英国媒体24日报道,在遭受埃博拉侵袭的西非国家,疾病除了带来死亡之外,也同样影响着人们的生活方式,人们握手、亲吻脸颊的习俗,和日常生活的所有方面,几乎都遭到了破坏。
消失的扣指声
利比里亚总统瑟利夫对利比里亚人说,“埃博拉不会击垮我们。”早些时候,瑟利夫还曾说,埃博拉破坏了利比里亚人的“生活方式”。报道称,她所说的,显然包括独特的利比里亚式握手。
这种握手俗称“利比里亚扣指”。文章称,这种方式听上去很痛苦,其实一点儿也不疼,不过技巧很难掌握。
扣指的程序是,像正常握手一样双手对接,然后,在断接的那一瞬间,互相扣动对方手指,引发两声清脆的啪啪声。
扣的有力、发出的声音清脆,都是荣誉的象征。声音越响亮,说明友谊越深厚。但是这一切也都成了历史。
记者称,他本人曾经多次前往利比里亚,而他简直“不敢想象”这会成为一个没有扣指声的国家。而对于利比里亚人而言,恐怕更是如此。
在整个西非也都一样。比如讲法语地区,传统上,人们见面打招呼要亲吻脸颊三次,这也必须停止。
文章称,就好像埃博拉这个可怕的疾病,让人丧命还不知足,还要将天生热情好客的西非人的“魂”也抽走。
“绝望措施”戒严
过去这个星期,利比里亚的邻国塞拉利昂采取了令人震惊的极端措施。埃博拉也给塞拉利昂带来沉重打击,医院里人满为患,食品价格飞涨。
为了控制病毒传播,塞拉利昂宣布全国戒严三天,所有的人都不准出门,医护人员在全国挨家挨户上门检查,查出所有感染病毒的人。
戒严不仅非常困难、而且非常危险。首先,塞拉利昂是否足够合格的医护人员去检查全国各地的每一所房子、每一个茅屋?这一点并不清楚。还有,发现可能染病的人之后怎么办?治疗中心已经人满为患了。
塞拉利昂政府说,绝望时刻必须采取绝望措施。但是,如果戒严真的见到了成效,这也将成为埃博拉全盘改变一个国家生活方式的例证。
大多数塞拉利昂人生活贫困,许多人靠街头摆摊、打零工为生。很少人家里存有大量的食品,更少数人有冰箱这类奢侈品。所以,人们必须天天出门,去工作,去购物。否则全家都吃不上饭。
当然了,埃博拉打击最严重的是染上病毒、垂死的病人以及他们的家属。不过,其它所有的人,生活中非常重要的一些东西也都受到了病毒的侵袭,比如购物,比如握手。
利比里亚总统在一次讲话中说,“我们正在和埃博拉作战,我们一定会赢。”到了那一天,西非人将重新获得的最宝贵的东西之一,就是又能自由地握手、亲吻了。
For Immediate Release: Tuesday, September 30, 2014
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(404) 639-3286
CDC and Texas Health Department Confirm First Ebola Case Diagnosed in the U.S.
The Centers for Disease Control and Prevention (CDC) confirmed today, through laboratory tests, the first case of Ebola to be diagnosed in the United States in a person who had traveled to Dallas, Texas from Liberia. The patient did not have symptoms when leaving West Africa, but developed symptoms approximately four days after arriving in the U.S. on Sept. 20.
The person fell ill on Sept. 24 and sought medical care at Texas Health Presbyterian Hospital of Dallas on Sept. 26. After developing symptoms consistent with Ebola, he was admitted to hospital on Sept. 28. Based on the person’s travel history and symptoms, CDC recommended testing for Ebola. The medical facility isolated the patient and sent specimens for testing at CDC and at a Texas lab participating in the CDC’s Laboratory Response Network. CDC and the Texas Health Department reported the laboratory test results to the medical center to inform the patient. A CDC team is being dispatched to Dallas to assist with the investigation.
“Ebola can be scary. But there’s all the difference in the world between the U.S. and parts of Africa where Ebola is spreading. The United States has a strong health care system and public health professionals who will make sure this case does not threaten our communities,” said CDC Director, Dr. Tom Frieden, M.D., M.P.H. “While it is not impossible that there could be additional cases associated with this patient in the coming weeks, I have no doubt that we will contain this.”
The ill person did not exhibit symptoms of Ebola during the flights from West Africa and CDC does not recommend that people on the same commercial airline flights undergo monitoring, as Ebola is contagious only if the person is experiencing active symptoms. The person reported developing symptoms several days after the return flight. Anyone concerned about possible exposure may call CDC-Info at 800-CDC-INFO for more information.
CDC recognizes that even a single case of Ebola diagnosed in the United States raises concerns. Knowing the possibility exists, medical and public health professionals across the country have been preparing to respond. CDC and public health officials in Texas are taking precautions to identify people who have had close personal contact with the ill person, and health care professionals have been reminded to use meticulous infection control at all times.
We do know how to stop Ebola’s further spread: thorough case finding, isolation of ill people, contacting people exposed to the ill person, and further isolation of contacts if they develop symptoms. The U.S. public health and medical systems have had prior experience with sporadic cases of diseases such as Ebola. In the past decade, the United States had 5 imported cases of viral hemorrhagic fever (VHF) diseases similar to Ebola (1 Marburg, 4 Lassa). None resulted in any transmission in the United States.
CDC has been anticipating and preparing for a case of Ebola in the United States. We have been:
The data health officials have seen in the past few decades since Ebola was discovered indicate that it is not spread through casual contact or through the air. Ebola is spread through direct contact with bodily fluids of a sick person or exposure to objects such as needles that have been contaminated. The illness has an average 8-10 day incubation period (although it ranges from 2 to 21 days); CDC recommends monitoring exposed people for symptoms a complete 21 days. People are not contagious after exposure unless they develop symptoms.
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http://www.cdc.gov/media/releases/2014/s930-ebola-confirmed-case.html
埃博拉病毒会演变成经空气传播吗
2014-10-09
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来源:生物3600 N- ^: u7 p: k- P
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多国升级埃博拉防控措施 [attach]64523[/attach] 美国本土确诊的首个埃博拉患者死亡,西班牙出现首例在欧洲境内感染埃博拉病毒的患者……面对可能“走出非洲”的埃博拉威胁,欧美多国升级了防控措施,实施更为严格的检测、监控和隔离。 首先是严防埃博拉输入境内。在美国本土第一例埃博拉患者8日上午死亡后数小时,美国政府宣布,纽约肯尼迪国际机场、华盛顿杜勒斯国际机场、新泽西州纽瓦克自由国际机场、芝加哥奥黑尔国际机场和亚特兰大国际机场从本周起加强对来自西非疫区旅客的检测。 来自疫区国家的旅客抵美后将被护送到机场一个专门区域用非接触式体温计测体温,并填写相关调查表,接受经过培训的海关人员的询问。如果旅客有发热或其他症状,或有埃博拉接触史,将由疾病控制和预防中心人员进行进一步评估,包括重新测量体温。如果还需要进一步评估或观察,旅客将被移送相关卫生机构。 此前,美国于今年7月底给航空公司发布了指导意见,要求阻止埃博拉患者或与其有过接触的人登机,在机上发现疑似患者立即将他们隔离,让他们戴上口罩等,还要求国民不要去西非旅行。 英国航空公司从8月初起,暂停飞往塞拉利昂和利比里亚的航班。法国航空公司从8月底起暂停飞往塞拉利昂首都弗里敦的航班,并采取了对登机乘客进行体温监测等措施。 其次是对患者和接触者进行严格监控和隔离。在马德里女护士特雷莎-罗梅罗成为首例欧洲境内感染埃博拉病毒者后,西班牙卫生部门就着手对相关风险人群进行确定和监控,截至8日,卫生部门已对30名医护人员和54名曾与罗梅罗有过接触的人进行严密监控,其中,罗梅罗的丈夫等5名“高风险”接触者住院隔离。 最早收治两名美国埃博拉患者的埃默里大学医院拥有一个负压隔离病区,病人呼吸的空气有机器24小时监控,最终会通过高效滤网过滤病原体后排出。由于按照重症病房的标准建设,从实验室检测到病人的各种治疗,全都可在隔离病区内部完成。一切离开病区的物品都经过高温消毒,然后焚毁。 第三是完善应急响应机制,规范操作程序。美国虽至今未发布针对西非疫情国家的贸易与旅行禁令,但早在两个月前美国疾控中心就启用了有“作战室”之称的“应急指挥中心”,并随着疫情的恶化,把响应级别调高至最高一级。这意味着“应急指挥中心”有超过350名专家在从事后勤、通信、分析、管理和其他支持工作,24小时全天候响应疫情。 法国卫生总局建议,任何人在离开疫区21天内出现38.5摄氏度以上的高烧都可被视为“疑似病例”;医护工作者在面对病人时应首先采取隔离措施,如给病人佩戴口罩、将其隔离等,随后立即联络急救中心,由急救中心联合大区卫生局和卫生监督研究所进行流行病学评估,以决定排除该病例还是将其升级为“可能病例”。一旦被列为“可能病例”,病人将由急救中心负责转送至配备高标准实验室、单人隔离病房等设施的指定医院,保证治疗的同时防范病毒传播。 英国政府危机应对委员会先后召开两次专门会议,商议相关事宜。主要目的是协调政府各部门行动,加强预防和监控,并商议一旦在英国发生疫情应采取的紧急措施。 西班牙正致力于调查罗梅罗染病的原因,并对防护操作中的一些失误进行反思。西班牙政府代表8日承认,这可能源于“一些程序方面的松懈”。而罗梅罗本人则在接受电话采访时自述,可能在没有防护装备时有所操作失误而接触到病毒。 此外,引导国民正确对待埃博拉至关重要。比如,多数美国国民相信埃博拉病毒无法通过水、空气或食物传播,传染途径只有病人或死者的体液和被污染的针头等工具。因此,只要找到病人并将他们隔离,就可以控制疫情。这得益于美国卫生机构所做的大量宣传工作。美国卫生官员几乎天天上电视为民众普及相关知识,并在社交网络上跟网民互动。
原文出处:http://1/news/show/11803.html
美国首例埃博拉患者死亡多国加强疫情防控
信息时报综合报道 综合外国媒体报道,10月8日,美国本土发现的首例埃博拉患者不治身亡,另有一名疑似病例入院接受检查。这令美国政府如临大敌。
面对可能“走出非洲”的埃博拉威胁,欧美多国升级了防控措施,实施更为严格的检测、监控和隔离。文字 综合新华、中国日报
争议
家属称其没得到“公平治疗”
位于得克萨斯州达拉斯市的得州健康长老会医院8日宣布,埃博拉患者托马斯·埃里克·邓肯于当天上午7时51分在该院病逝,享年42岁。
上月20日,邓肯从西非国家利比里亚抵美探亲,24日开始出现埃博拉症状,25日前往医院就诊时未被及时诊断出病情,28日病情恶化被送入院,直至30日才被确诊为美国本土发现的首例埃博拉病例。
“在此之前,美国没有人死于埃博拉,这是第一次!”得知邓肯病逝,他的家人在感到悲痛的同时也很愤怒,宣称邓肯“没能得到公平的治疗”。
质疑一:得不到幸存者输血 没用试验药
邓肯的家人认为,如果邓肯同其他几名在美国接受治疗的埃博拉患者一样,也能得到埃博拉幸存者的输血或者使用试验性药物ZMapp,他可能会被治愈。
对于上述质疑,美国官方给出的解释是,埃博拉幸存者的血型与邓肯“不匹配”,以及ZMapp药物已经完全用尽,而生产一批新药需要花费数月。
质疑二:医院没及时收治病患
除此之外,邓肯的家人还指责院方没能及时收治病患,延误了最佳治疗时机。8日,邓肯的母亲在其家庭发言人杰西·杰克逊的陪同下公开露面。杰克逊暗示,可能会对邓肯的治疗方采取法律行动,“他生病了去医院看病却被拒绝,这是整件事情的转折点”。
目前,得州卫生部门必须迅速处理邓肯的遗体。根据美国疾控中心发布的指引,埃博拉患者死后,其尸体需立即用塑料裹尸布包好,并用双层防漏尸体袋封存,就连死者身上的输液管等医疗器具都不能拔下,而后送去火葬,以彻底消灭尸体上留存的埃博拉病毒。所有程序完毕后,死者的骨灰将被送还给家属。
疫情
另一疑似病例现身达拉斯
迈克尔·莫尼格是达拉斯县警长办公室的一位雇员,因出现埃博拉疑似症状,8日他被送往医院接受检查。这一消息已得到达拉斯当局的证实。
据当地媒体报道,莫尼格此前与感染埃博拉病逝的邓肯有过接触,他在没有穿戴防护装备的情况下进入邓肯入院前居住的公寓,让对方签署一份隔离令。
莫尼格的儿子洛根表示,自上周起,他的爸爸开始定时测量体温,后来感到疲乏和胃痛,于是决定去医院检查一下。“他在公寓里待的时间非常短,并且没有触碰过邓肯本人或者邓肯的体液。”
一位政府官员表示,莫尼格感染埃博拉病毒的“风险非常小”,当局会谨慎应对此事。
应对
多国加强
埃博拉防控措施
严防埃博拉输入境内
在美国本土第一例埃博拉患者8日上午死亡后数小时,美国政府宣布,纽约肯尼迪国际机场、华盛顿杜勒斯国际机场、新泽西州纽瓦克自由国际机场、芝加哥奥黑尔国际机场和亚特兰大国际机场从本周起加强对来自西非疫区旅客的检测。
来自疫区国家的旅客抵美后将被护送到机场一个专门区域用非接触式体温计测体温,并填写相关调查表,接受经过培训的海关人员的询问。如果旅客有发热或其他症状,或有埃博拉接触史,将由疾病控制和预防中心人员进行进一步评估,包括重新测量体温。如果还需要进一步评估或观察,旅客将被移送相关卫生机构。
英国航空公司从8月初起,暂停飞往塞拉利昂和利比里亚的航班。法国航空公司从8月底起暂停飞往塞拉利昂首都弗里敦的航班,并采取了对登机乘客进行体温监测等措施。
严格监控隔离患者和接触者
在马德里女护士特雷莎-罗梅罗成为首例欧洲境内感染埃博拉病毒者后,西班牙卫生部门就着手对相关风险人群进行确定和监控,截至8日,卫生部门已对30名医护人员和54名曾与罗梅罗有过接触的人进行严密监控,其中,罗梅罗的丈夫等5名“高风险”接触者住院隔离。
最早收治两名美国埃博拉患者的埃默里大学医院拥有一个负压隔离病区,病人呼吸的空气有机器24小时监控,最终会通过高效滤网过滤病原体后排出。由于按照重症病房的标准建设,从实验室检测到病人的各种治疗,全都可在隔离病区内部完成。一切离开病区的物品都经过高温消毒,然后焚毁。
完善应急机制,规范操作程序
早在两个月前美国疾控中心就启用了有“作战室”之称的“应急指挥中心”,并随着疫情的恶化,把响应级别调高至最高一级,有超过350名专家在从事后勤、通信、分析、管理和其他支持工作,24小时全天候响应疫情。
法国卫生总局建议,任何人在离开疫区21天内出现38.5摄氏度以上的高烧都可被视为“疑似病例”;医护工作者在面对病人时应首先采取隔离措施,随后由急救中心联合大区卫生局和卫生监督研究所进行流行病学评估,以决定排除该病例还是将其升级为“可能病例”。一旦被列为“可能病例”,病人将被转送至指定医院,保证治疗的同时防范病毒传播。
西班牙正致力于调查罗梅罗染病的原因,并对防护操作中的一些失误进行反思。西班牙政府代表8日承认,这可能源于“一些程序方面的松懈”。而罗梅罗本人则在接受电话采访时自述,可能在没有防护装备时有所操作失误而接触到病毒。
2014-11-19 09:32 来源:中国科学报 6 P1 E8 B$ q% Q/ l
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图片来源:VIRALZONE/瑞士生物信息学研究所 随着埃博拉病毒横扫西非,科学家缺乏重要基因数据来解答引发众多担忧的猜测:这种病毒会变得更具传染性和更致命吗?它会发生变化,让其逃避诊断测试或疫苗吗?非洲和欧洲实验室的冰箱里存放着取自埃博拉患者的数千份血液样本,但它们并未被使用,且少数几个获得新基因数据的研究小组并未公开信息。 研究人员渴望近距离观察病毒可能是如何进化的。英国爱丁堡大学研究传染病的进化生物学家Andrew Rambaut表示,除了要回答有关其毒性的问题外,基因数据还能揭示疾病流行的细节,包括传播特点以及病毒从动物宿主传播到人类需要多久。“如果可以及时完成检测,就可以确切了解到发生了什么。”他说。但面对官僚障碍和记录混乱等问题,科学家不得不等待。 今年8月,研究人员公布了塞拉利昂78位患者感染的埃博拉病毒的99个基因组,让全世界能够近距离看到埃博拉病毒分子。该分析包含了当时塞拉利昂已知的一半多病例。 研究结果一经确定,科学家就将基因数据放置在了公共数据库中。这些数据揭示了在塞拉利昂疫情初期,病毒在人际传播时是如何变化的,在之后的病例中,一种变体消失,而另一种则凸显出来。自那时起,这次疾病转变成了传染性疾病,但美国罗德研究所的Pardis Sabeti和Stephen Gire领衔的该研究小组却没能从塞拉利昂获得任何新样本。其他研究小组也遇到了类似困境。 数位研究人员均表示,从当地身陷困境的健康部门获得样本输出许可十分困难。“我只能假设当地的相关系统不堪重负,制备样本不是其优先项目。”Rambaut说。他也是8月份发表的论文的合作者。 德国Bernhard Nocht热带医学研究所(BNI)病毒学家、欧洲移动实验室(EMLab)联盟协调人Stephan Gnther表示,他们无法从尼日利亚和利比里亚输出样本。但他表示,BNI从3月开始一直在接收EMLab项目的几内亚样本,目前已经接近3000个。BNI代表几内亚政府将这些样本储存在高安全级别办公室里,几内亚政府仍是这些样本的所有者。 Gnther和同事还未对这些样本进行测序,原因是联盟的同事正忙于支援被感染国家的疾病监测中心。“我们全部忙于现场工作。”Gnther说,“人员是很大问题。”但他指出,欧盟新拨了170万欧元给EMLab进行埃博拉研究,问题或能得到缓解。 在法国,巴斯德研究所也经历了西非样本输入的困境,但他们仍计划迅速测序新病毒基因。巴斯德研究所埃博拉特别小组协调人Felix Rey表示,该研究所位于达喀尔(塞内加尔首都)的实验室最近收到来自几内亚的样本。达喀尔实验室将提取RNA,并送到巴黎进行高通量测序。“我们希望下个月能利用一二百个样本测序该病毒。”Rey说。 另外,与Sabeti合作的杜兰大学Robert Garry 表示,Sabeti和同事也可能很快获得塞拉利昂样本。但为了加速研究,她和同事正试着弄到经费,将测序机器运到西非。“如果我们不能在这里(美国)得到样本,那么我们将在那里进行测序。”她说。 但仅靠血液样本不足以进行基因组学研究。研究人员还至少需要知道每位患者来自哪里,理论上还需要患者存活或死亡等临床信息。“只有当获得这些数据后,你才能找到对测序有用的信息。”Gnther说。但由于记录质量不一,这些信息通常已经丢失。他和同事目前正与无国界医生组织和世界卫生组织进行合作,以便将样本和相关信息进行匹配,但他表示,建设数据库是一项耗时耗力的工作。 同时,最初一批塞拉利昂样本产生的若干病毒序列结果并没有公布。美国疾控中心(CDC)在8月宣布测序了取自在该国接受治疗的患者的样本,但数据并没有被放入任何公共基因库中。Rambaut表示,这令人十分遗憾。“美国的病例来自利比里亚,迄今为止我们没有任何基因序列信息来自那里,即使一个基因组也十分有用。”他说。但CDC生物信息学家Duncan MacCannell在接受《科学》杂志采访时表示,这些序列已经“与公共健康界积极共享和讨论过了”。他表示,CDC正着手将序列信息提交给公共数据库。 Rambaut表示,新序列可能不会显示该病毒正在出现新的攻击或传播方式,但有助于得出更清晰的疫情暴发图。他还指出,一连串类似病毒可能指向一个传播热点区域,同时异常高的多样性表明尚有许多病例未被发现。 “更早的基因数据还表明,埃博拉病毒正经历快速变化,但这并不一定表明它正变得越来越危险。”Rambaut说,“大部分RNA病毒突变速度都很迅速,但适应性和功能性改变却是很慢的过程。”麻疹病毒变异的速度与埃博拉病毒类似,但却尚未成功脱离一次患病、终身免疫或用疫苗进行控制。虽然疫情十分严重,但Rambaut说,“没有理由怀疑,埃博拉病毒会迅速改变生命周期或传播模式
”。(张章)
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