致命的埃博拉疫情继续在刚果民主共和国蔓延，全球卫生官员警告说，“我们仍然落后。”
根据刚果卫生部和疾病控制和预防中心(CDC)的数据，截至周三，已确认363例埃博拉病例和62例死亡。卫生官员说，在邻国乌干达，已确认15例病例和1例死亡。
最新的刚果民主共和国埃博拉疫情报告显示，疫情现已蔓延至曼巴萨，这是一个新的卫生区，位于伊图里省矿业城镇蒙瓦卢因以南160多公里处，那里是病例集中的地方。这表明病毒正继续在地理上传播。
“疫情有一个很大的开端，我们仍然落后...但我们正在迎头赶上，”世界卫生组织总干事特德罗斯·阿达诺姆·盖布雷耶苏斯博士在周三的一次新闻发布会上说。
最近，世卫组织经过调查排除了数百起疑似病例。尽管一些当地卫生官员表示，社区传播可能正在放缓，但许多公共卫生专家警告说，数据非常不完整。专家们还指出，接触者追踪薄弱，远远低于控制疫情所需的水平。
然而，专家们承认，公共卫生应对措施正在加强，卫生当局对确诊病例的数量有了更好的了解。
Megan Coffee博士是一名传染病医生，也是援助组织国际救援委员会(IRC)卫生部门传染病方面的高级专家，他强调了在他们试图控制疫情时澄清某些细节的重要性。
她告诉美国广播公司新闻频道(ABC News)，“为了能够说出病死率是多少，已被确认的病例百分比是多少，以及潜在的传播链中可能接触并可能发展成埃博拉的人的百分比是多少。”
数百个疑似病例被排除
周二，世卫组织表示，有116例疑似病例，经过调查，数百例疑似病例被排除。
此前，全球卫生机构周五表示，906例疑似病例正在调查中。然而，在英国《金融时报》周日发表的一份声明中，非洲疾病控制和预防中心(Africa Centres for Disease Control and Prevention)总干事写道，疑似病例超过1100例。
据路透社报道，当被问及这一大幅下降时，世卫组织发言人克里斯蒂安·林德梅尔在日内瓦总部告诉记者，数百例病例“已经被清除，要么患有其他疾病，要么只是发烧，没有其他症状”。
林德梅尔补充说，随着越来越多的人接受测试，这些数字将会发生变化，Coffee同意这一声明。
“这些数字会有些变化，因为疑似病例可以被排除在外，”Coffee说。“和新的人可以识别;新的嫌疑人随时都可能被发现。所以，这些数字总是在变化。”
Syracuse的Maxwell Schoo of Citizenship and Public Affairs的公共卫生副教授Brittany Kmush专门研究传染病流行病学和疫情监测，她告诉ABC News，记住埃博拉的潜伏期(接触病原体和首次出现症状之间的时间)最长为21天，这一点很重要。
她说，世卫组织宣布此次疫情为国际关注的突发公共卫生事件还不到21天，因此“疫情的发展轨迹”仍不清楚。
“在5月17日受到辐射的人可能还没有生病，”她说。“然后是疫情被发现时的规模...这意味着有很多未被发现的传播，这意味着有很多我们不知道的病例和我们知道的接触。”
努力追踪接触者
应对工作面临的最大问题之一是接触者追踪，这涉及识别与感染者接触的任何人，以便他们可以寻求医疗护理、检测或隔离。
约44%的接触者在伊图里被追踪，伊图里是刚果民主共和国东北部受影响的主要省份。世卫组织首席谭德塞周三表示，这一数字需要增加到90%左右。
Coffee说，在一个有些人可能不信任当局，而另一些人否认埃博拉是一种真正的病毒或自己被感染的地区，确定每个接触者是很困难的。
此外，她说，很难在不同地区之间旅行，特别是在更偏远的农村地区，以确定病例和接触者。
“在疫情爆发的早期，很难知道你有所有的传播链，”Coffee说。“在一场更大的疫情中，往往会有一连串的传播，只是你没有注意到。”
Kmush补充说，埃博拉病毒带来了很多耻辱，人们可能担心向卫生当局报告他们所有的接触。
她说:“很难确定所有的接触者，并对他们进行适当的跟踪，特别是因为国际援助界确实缺乏资源。”。“你不想缺少人员和资源来追踪接触者，也不想缺少可供人们隔离和隔离的地方。”
Coffee补充说，刚果民主共和国的埃博拉热点之一是一个拥有金矿和许多移民工人的地区，这使得追踪病例的能力变得复杂。
“当你进行联系追踪时，当每个人都有一个固定的地址时，就容易多了;他们在那个地址住了一辈子，所有的邻居都认识他们，”她说。“当你的人口在流动时，你会更难找到像。你知道怎么联系一周前在这里的亨利，对吗?"
What we know about the spread of Ebola amid growing outbreak in DRC
A deadly Ebola outbreak is continuing to spread across the Democratic Republic of the Congo, with global health officials warning that "we are still behind."
As of Wednesday, 363 cases of Ebola and 62 deaths have been confirmed, according to the Congo Ministry of Health and theCenters for Disease Control and Prevention(CDC). In neighboring Uganda, 15 cases and one death have been confirmed, health officials said.
The latest DRC Ebola situation report shows the outbreak has now reached Mambasa, a new health zone located more than 160 kilometers south of the mining town of Mongbwaluin in Ituri province, where cases have been concentrated. This suggests the virus is continuing to spread geographically.
"The outbreak had a big head start and we are still behind ... but we're catching up," Dr. Tedros Adhanom Ghebreyesus, the director-general of the World Health Organization, said during apress briefingon Wednesday.
Recently, the WHO ruled out hundreds of suspected cases after investigation. Although some local health officials suggested that community transmission may be slowing, many public health specialists cautioned that data is very incomplete. The specialists also noted that contact tracing is weak and far below the level needed to contain the outbreak.
However, the specialists acknowledge that the public health response is ramping up and that health authorities are getting a better sense of how many confirmed cases there are.
Dr. Megan Coffee, an infectious disease physicianand a senior specialist in infectious diseases in health unit of the aid organization International Rescue Committee (IRC) highlighted the importance of clarifying certain details as they try to control the outbreak.
"To be able to say what is the case fatality, what is the percentage of cases that have been identified, and what have been the percentage of people who are potentially in a chain of transmission may been exposed and may develop Ebola," she told ABC News.
Hundreds of suspected cases ruled out
On Tuesday, the WHO said there were 116 suspected cases, with hundreds of suspected cases ruled out after investigation.
That came after the global health agency said on Friday that 906 suspected cases were under investigation. However, in anop-edby published in the Financial Times on Sunday, the director-general of the Africa Centres for Disease Control and Prevention, wrote that there were more than 1,100 suspected cases.
When asked about the massive drop, WHO spokesperson Christian Lindmeier told reporters at the agency's headquarters in Geneva that hundreds of cases "have been cleared out and have either other diseases or have just had fever and nothing else," according toReuters.
Lindmeier added that the numbers will shift as more people get tested, a statement Coffee agreed with.
"Those numbers will change a bit because suspected cases can be ruled in or out," Coffee said. "And new people can be identified; new suspects can be identified at any point. So, these are numbers that are always changing."
Brittany Kmush, an associate professor of public health at Syracuse's Maxwell Schoo of Citizenship and Public Affairs who specializes in infectious disease epidemiology and outbreak surveillance, told ABC News it's important to keep in mind that the incubation period -- the time between exposure to a pathogen and the first appearance of symptoms -- for Ebola is up to 21 days.
She said it has not even been 21 days since the WHOdeclaredthe outbreak to be a public health emergency of international concern, so "the trajectory of this epidemic" remains unclear.
"People who were exposed on May 17 may not even be sick yet," she said. "And then there's the size of the epidemic when it was recognized ... and so that means there was a lot of undetected circulation, which means there's a lot of cases that we don't know about and contacts that we know about."
Struggles for contact tracing
One of the biggest issues facing the response effort is contact tracing, which involves identifying anyone exposed to infected individuals so they can seek medical care, testing or quarantine.
About 44% of contacts are being traced in Ituri, the main affected province in the northeastern DRC. WHO chief Tedros said on Wednesday that this figure needs to increase to about 90%.
Coffee said identifying every contact is difficult in an area where some people may not trust the authorities and others are in denial about Ebola being a real virus or being infected themselves.
Additionally, she said it can be hard to travel between areas, especially in more rural or remote regions, to identify cases and contacts.
"It's very, very hard early in an outbreak to know that you have all the chains of transmission," Coffee said. "There will often be chains of transmissions in a larger outbreak that you just haven't noticed."
Kmush added that there's a lot of stigma around Ebola and people may be worried about reporting all their contacts to health authorities.
"It's going to be very difficult to get all the contacts identified and followed properly, especially since the international aid community is really short on resources," she said. "You don't want to be short on people and resources to do the contact tracing, short on places to go for people to quarantine and isolate."
Coffee added that that one of the Ebola hotspots in the DRC is an area with a gold mine and many migrant workers, which has complicated the ability to track cases.
"When you do contact tracing, it's a lot easier when everyone has a fixed address; they've lived in that address their entire life, and all of their neighbors know them," she said. "When you have populations that are on the move, you'll have more of a difficulty in tracking down like. 'You know how to contact Henry who was here a week ago, right?'"
