'Double-edged sword'

DW: There's a lot of curiosity about experimental Ebola drugs such as that used to treat US patients Kent Brantly and Nancy Writebol, both of whom survived. Do you think they can play a wider role in the outbreak in West Africa?

Barbara Knust: The experimental drugs have been used in just a few patients. Certainly there's a lot of interest among people around the world about whether they might be helpful. There are also additional therapeutics that have been under discussion. But there's a lot of work to be done to find out what the therapeutic benefit would be. It's important to move that work forward - especially in the context of this outbreak. But it's also important to make sure that they're safe for people and that there is some measured effectiveness as well.

There are ethical issues involved - and very difficult decisions to be made when a drug is in such restricted supply. What would be your golden rule for negotiating those ethical dilemmas?

The ethical dilemmas confront us with a double-edged sword. On the one hand, we have a drug that really hasn't been tested on people. And if we put it into a population in Africa that is disadvantaged, people might say: You're experimenting on these people. But if you don't provide it to these people who are so clearly affected by the disease, and where there is clearly such a crisis, then people say: You're not helping them, you're not helping the situation. I think it's very important to make sure that these drugs are effective and safe before they're given to a population that already has some issues with resisting and not trusting public health efforts. If it isn't safe and is put into a population that doesn't trust those efforts, it makes the situation worse.

But in the longer run, do you see these drugs as a promising line of research? Do you think they might be the route to a solution?

I would love to see coming out of this something like a vaccine that could prevent disease in a population. For someone like me, who thinks about diseases in populations and how to prevent them, I'd much rather think on those lines than think about being the fire department that we currently are - where we have a fire that's blazing out of control but we didn't have a way to prevent the fire from starting in the first place.

Meanwhile the outbreak in West Africa keeps getting bigger. The World Health Organization is now talking about total cases reaching 20,000 in the coming months. Why is this outbreak so big?

The outbreak is really spreading rapidly, and it has a lot to do with the locations where people are getting infected: that we essentially have outbreaks going on in slum conditions, particularly in Liberia and Sierra Leone, where people have a lot of contact. There is also a lot of difficulty in identifying the people who are most likely to become ill, which is how we've previously managed outbreaks. At this point we have to be thinking about things other than tracing the contacts - but thinking about providing good care, and keeping the people who are sick from passing on the disease to others.

Do you think this is the shape of Ebola outbreaks to come? Can we expect more like this in the future?

Not necessarily. The typical situation where people become infected with Ebola still remains remote areas. In West Africa there are remote areas involved, but there are also good roads - which is not the case in a lot of areas where we've had outbreaks in the past. The ability for sick people - and people who were exposed - to move across these countries easily may have played a large role in how this outbreak spread quite quickly. The other thing that continues to play a large role is the resistance of communities to participate in outbreak control efforts. There are still a lot of areas where communities will not let the response workers go - and there is a fear of violence. That's something that still needs to be addressed. There's a lot of work going on to try and get communities to participate and bring the outbreak under control in those areas.

Was the international community too slow to identify just how serious this outbreak was?

It was a situation where, because of the resistance of the communities, sometimes we didn't have good information. The term "shadow zones" has been used - areas where people were not able to go in and collect the information needed to assess how large the outbreak was. I think that did affect the efforts and where efforts were placed. That continues to be a problem. We have to continue to work on collecting intelligence about the outbreak and understanding about it - even in places where we can't get the access needed to count cases like we typically would.

Dr Barbara Knust is an epidemiologist and a team lead for Ebola response at the Centers for Disease Control, which is based in Atlanta, Georgia.