As part of the BBC's digital conference on Ebola, some of the key decision-makers in the fight against the deadly virus have answered your questions in a live Facebook Q&A.
Ebola has killed almost 10,000 people, primarily in Guinea, Liberia and Sierra Leone, where there is still some way to go until the virus is eliminated.
The first session on "Getting to zero" featured UN Special Envoy on Ebola, David Nabarro and the World Health Organization's Dr Bruce Aylward.
This is an edited version of the session.
Question from No Mey: Do you think airport screenings are a viable way to tackle this disease?
David Nabarro answers: Exit screening - as passengers board airplanes - is important. Persons should not travel if they have a history of contact with someone who has Ebola or if symptomatic. Entry screening is valuable reassurance.
Question from Paul Harper: How long will UNMEER last?
David Nabarro answers: UNMEER [UN Mission for Emergency Ebola Response] allows the UN system to offer high-level coordination of those supporting the response (especially the UN system) additional logistics and the capacity for a surge in the response where it is needed. Over time there will be a transition and the activities of UNMEER will be taken on by other entities within the United Nations system. The transition will occur when the entities are ready to take on UNMEER functions.
Question from LaShonda Steward: What are your immediate, short and long-term recommendations for health systems strengthening - specifically in Sierra Leone?
David Nabarro answers: The task ahead is to ensure that health systems are able to ensure people's security in the face of infectious diseases: this means surveillance, analysis, prompt action to investigate possible outbreaks and - when necessary - scaled up responses. Always vital to involve communities fully in detection and response.
Nabarro on future epidemic
Question from Theo B. Amissah: Is there a way to re-purpose structurally sound Ebola Treatment Units/ Centres? If so, have any organisations or governments started thinking about doing this?
David Nabarro answers: Yes - one has already been re-purposed (in Liberia) to provide high-quality medical care to persons with serious illness. Others will be re-purposed as Primary Health Care Units.
Question from Juliet Kidwell: What new steps are being taken to prevent an epidemic like this from happening again?
David Nabarro answers: This is a vitally important part of establishing trust between responders and communities. The whole focus of lessons-learnt exercises currently underway is to ensure that the response to any future outbreaks is rapid and effective, and to prevent major epidemics.
Question from Hassan Gba-Kamara Why is the virus still ravaging Sierra Leone compared to the other two countries who seem to be winning the fight.
David Nabarro answers: The three affected countries are contiguous, borders are porous - if the virus is present in one it is present in all three. In some districts within Sierra Leone - including those in the Kisse Triangle where this outbreak started - there are zero cases being reported. In other parts of the country - especially the west - incidence is relatively high. I would not say that Sierra Leone is being "ravaged" more than the other two countries.
Dr Bruce Aylward on WHO's response
Question from Michael Odok: What is the World Health Organization doing to eliminate Ebola completely from this globe?.
Bruce Aylward answers: WHO is working hard to help countries improve their surveillance systems to rapidly find and control Ebola when it emerges in the human population. We are also supporting a wide range of vaccine trials to develop new tools for preventing outbreaks.
Question from Adama Juldeh: Why did the WHO not make more of an effort to research or work with researchers for a cure for Ebola in spite of the fact it was discovered 40 years ago?
Bruce Aylward answers: WHO has in fact supported and promoted research for vaccines, diagnostics and therapeutics against Ebola and a wide range of other "neglected" diseases for years. This outbreak has helped provide the impetus needed to move promising approaches into fast-track development processes that we expect will help with both the tail-end of this crisis and future outbreaks
Question from Jonathan Pevec: Viruses mutate. Will this one become airborne?
Bruce Aylward answers: There is no evidence that this virus will become airborne. The mode and mechanism of transmission of this virus has been very stable for decades.
Question Saeed Chicharito Omaley: Is there hope for zero cases at the end of the year?
Bruce Aylward answers: Absolutely - the strategies being employed are proven and will work. Over the past 12 months a huge amount has been learned about effectively adapting these strategies to the intensive transmission, wide geographic distribution and urban environments we have seen in West Africa. The over-riding and only major challenges now are ensuring full community engagement and ownership of the response and sufficient financing!
Helen Clarke on rebuilding for the future
Question from Sam Phodogoma: What measures are in place to help survivors quickly rebuild their lives, so they can in turn help bring back confidence in their communities?
Helen Clark answers: Survivors need support to resume their jobs and livelihoods, and psychosocial support in many cases too. This must be part of the recovery partnership.
Question from Kamara Abdulai: How will the West African affected countries regain their glories academically and economically after being threatened by the Ebola virus?
Helen Clark answers: Once declared Ebola-free, the three countries do have a good prospect of returning to reasonable economic growth rates. It will be important to prioritise investment in strengthening resilience to shocks like that of Ebola - stronger institutions, systems, and services are needed.
Question from Alhaji Alimu Barrie: The Ebola virus has caused so many problems in Sierra Leone, how would your organisation help rebuild our economy?
Helen Clark answers: All economic sectors were impacted by the crisis. UN agencies and other partners are moving to support small holders and local traders to get re-established.
Helen Clarke on stigma
Question from Merry Morlai: What is going to be done to stop the outside world from stigmatising the worst Ebola-affected countries?
Helen Clark answers: As we move towards zero new cases, I am confident that stigma against the countries will reduce. But it is vital to get there to get a return of investment, flights, and open borders.
Question from Adam Yusuf: How can UN eradicate discrimination against Ebola victims?
Helen Clark answers: The UN advocates for zero stigma and discrimination against survivors. They have a right to be able to resume their normal activities.
Question from James Daniel: What measure have you put in place so that money meant for reconstruction and rebuilding of Ebola victims gets to them without getting into wrong hands?
Helen Clark answers: Mutual accountability and transparency in the use of funds is vital to retain the confidence of the publics of the three countries and international partners.