Modern plagues: Ebola

Unfortunately, while Yersinia pestis may now be more-or-less under control, there are other diseases around today that have similarly devastating effects, particularly in developing countries, which have the same overcrowding and sanitation issues London faced in the 17th Century. One 'modern plague' that has been in the headlines a lot recently is Ebola. Dr Kevin Wing works at the Cambridge University Department of Medicine and The London School of Hygiene and Tropical Medicine, and recently spent time working at an Ebola Treatment Centre in Sierra Leone. He explained to Chris Smith why the recent epidemic was so dramatic...

Kevin - In the recent outbreak, the key point was that the countries where it was especially bad had very weak health systems. So, the infrastructure that was there was not able to cope with such an outbreak in any way.

Chris - And that's the crux of it because you've just got a very poor country, very poor health services, and there's a big opportunity for diseases to just escape.

Kevin - Well, I think if you look at some of the other countries that Ebola did go to apart from Sierra Leone, Guinea and Liberia, you can see that there was only ever a few cases in those other countries. For example, I think Mali had two cases and there was one case in Nigeria. The reason that it didn't spread in the same way was because those countries had health systems that were more able to cope.

Chris - Your feeling then is that if we look at what happened with Ebola in countries like Sierra Leone, this is a pretty good proxy of what was probably going on in London to an extent during things like the Black Death.

Kevin - Yeah, absolutely. I think when Ebola hit Sierra Leone for example, there was a real problem and in fact, there still is in actually persuading a lot of Sierra Leoneans that Ebola was real. Obviously, with the coverage that we get in the media here, that sounds incredible but it really was a problem where you've got culturally and very engrained practices and beliefs. And also, suspicion of people coming in and sort of dictating. So, it was a very, very sensitive management at the beginning of the outbreak.

Chris - People have done analyses of what they think the recipe is behind the sort of disaster that was Ebola because we first discovered Ebola more than 40 years ago. In the entire time since then it's killed fewer people than it did in this one outbreak. So, people were obviously asking, "Why here? why now? Why has Ebola done this?" Some have suggested actually, it's because of population. There are more people around and there are more mobile people around.

Kevin - Yeah, well I think again, taking Sierra Leone as an example, when it entered the country, there was an initial - I think it was actually a funeral of the traditional healer and from that one funeral, there was something like 300 cases. And then it spread across rural areas relatively quickly and it was very difficult to trace in those rural areas. But the big concern was that what would happen when it got to the capital, Freetown. In fact, it was in Freetown where there's a very high density of housing and people living in close quarters that it really exploded. There's a huge number of cases that came from the capital.

Chris - This week, at the beginning, we were hearing about things that people believed were causes and cures of the original plague Yersinia pestis. Ebola is obviously a virus. It's a little bit different but are people similarly misinformed in Africa and that's part of the problem with dealing with how you stop it.

Kevin - Well, I think at the beginning of the outbreak, it was very difficult to get the communication across. In fact, it was a rainy season for example and being able to set up and communicate actually what was happening, and getting health education across is very difficult. And the particular issue is that one of the traditional practices is to wash the bodies of people who've died at funerals. In fact, dead bodies are secreting the highest amount of virus. In fact, that's the most infective situation. But it's very difficult to get people to try and change that behaviour and very upsetting as well for people not to be able to watch their loved one.

Chris - I think it's worse than just washing. They were washing and drinking the water they wash the bodies with, weren't they?

Kevin - Yeah, absolutely. This behaviour, it's very difficult to change and we've heard already about having the plague that the burial was very important in the same way for Ebola. The burial practices were really key - once you get those changed, that's a big step.

Chris - What can we do with modern science in the modern era to try to prevent Ebola, but things like Ebola as well coming back and doing this to us again?

Kevin - It's interesting because when people think of sub-Saharan Africa, they think of - well at the moment obviously, they think of Ebola, but they think of other infectious diseases such as HIV, tuberculosis and malaria. And in fact, what the big challenge that sub-Saharan Africa is facing now and will face, and we don't hear so much about is actually from diseases that are not infectious. So, this is the so-called non-communicable diseases. What I mean by that is diseases such as diabetes, cardiovascular diseases and respiratory diseases. And in fact, by 2030, it's predicted that the deaths from those diseases will be greater than the deaths that traditionally are the leading causes of death in Africa such as infectious diseases, under-nutrition and maternal and perinatal death.

Chris - One of the things that got highlighted in my view, a bit late in the Ebola story though was that: along comes this virus and it decimates the healthcare system which was already pretty feeble. And that meant that there's now nowhere for a woman to go and have a baby with any degree of safety. There's nowhere for anyone to get any treatment whatsoever for a common disease like malaria or a flare-up of TB. So, you have one outbreak of one disease that then causes a snowball effect, destroying lots of other lives through other consequences.

Kevin - Yeah, absolutely. I mean, the solution for that is obviously very difficult in these countries which are very resource poor and do not have effective health systems. But I think going back to my point about non-communicable diseases, in other African countries, if we don't get a handle on these non-communicable diseases such as diabetes and heart disease. Then in fact, the health systems that are already working are going to be under so much pressure that something like the outbreak we've seen could happen again.

Chris - What about the world as a whole, because many people say there's so many of us on Earth now and we're so mobile that we really are cruising for a biological bruising? Because we've got up in the air right now around the planet, a million people aboard airplanes. No cities more than 24 hours from any other city which is inside the incubation period of most infectious diseases. So unlike when the great Black Death plagues were knocking around, people had to go everywhere, they were going to go by boat and it took them months. Now, you can be on the other side of the world and spreading a disease before you even know you've caught the disease.

Kevin - Yeah. That is something that came up in the media a lot. In fact, I think during the outbreak, the international community really only got involved when those concerns came up which was obviously a tragedy for the countries involved. But I think that people are always going to want to travel and the way that we live is the way we live for better or worse, but what we really need to focus on is looking at the burden of disease in these countries and more and more of that is these non-infectious diseases and looking at research to help handle those so that then we're in a position to help with infectious diseases that emerge.

Chris - Kevin Wing, thank you very much.

Ginny - One of the factors that has a huge impact on the spread of disease is population density. So the more people you have packed together, the faster a disease can spread and that was one of the big problems with this outbreak of the plague. So, I have a little demo here to show you how that works and it involves cake. So, I have two cakes here and they're going to represent our two different kinds of population. On the left hand cake, there are 8 candles and those represent people. On that cake, they're very crunched together. They're all up one end of the cake. They're very close together. On the other one, we've got the same number of candles, but they're nicely spread-out. Now what we're going to do is light one candle at each end of the cake and that's going to represent someone catching a disease and we're going and watch and see if that disease starts to spread. And if so, in which cake it spreads more quickly. So, I've now got one candle lit at each end and I've just got a fan here and I'm just very gently fanning the two cakes. So, who can see something happening?

Audience member - On the cake where the candles are really bunched up, it's spreading and on the one where they're spread out, it's not spreading at all.

Ginny - Exactly. So, I've now actually got three candles lit on the cake where the candles which are representing our people remember, are very closely packed because what's happening is, as I'm fanning the flames, they're sort of moving around a little bit and they're jumping from one person to the next or from one candle to the next. They're now all lit, whereas on the other one, which I've just started fanning a bit more because it wasn't doing anything, I've now managed to blow out the first candle which is quite representative actually because if there's one person infected, they're going to either recover or they're going to die. But if there's no one else around them for them to infect, that's where the disease ends. And that cake now has not a single candle lit on it whereas the other one where they were close together and the infection could jump from one to the other, they're now all lit. This is a really interesting demo because not only does it model the spread of infection. It actually also links very nicely to what we're going to talk about next which is the great fire of London.