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STEVE INSKEEP, HOST: Three companies are working to develop drugs that can battle Ebola. They want to fight a disease that has killed around 1,000 people in the latest outbreak alone and has made headlines worldwide. This disease has been known to scientists for decades, but as yet no drug has been proven to treat it. The free market has not produced a solution, a situation the United States government has been trying to correct. NPR's Richard Harris is covering this story. Hi, Richard.

RICHARD HARRIS, BYLINE: Hi, Steve.

INSKEEP: OK, so why hasn't the market produced a drug that battles Ebola?

HARRIS: Well, because there are so few people who die from this disease. In the history of this disease, probably fewer than 3,000 known deaths since 1976.

INSKEEP: Which is a lot of people, but on the scale of diseases...

HARRIS: Absolutely. Most drug companies are interested in drugs that will treat millions of people. And if you think about it, you know, it costs hundreds of millions of dollars to develop a drug. So you're talking about a drug that would be ridiculously expensive, on top of the fact that the people who are getting sick and dying are poor people who have no money at all, essentially.

INSKEEP: And they're loss of interest to for-profit companies. What is the United States government trying to do about this?

HARRIS: Well, the U.S. government got interested in this because of its concerns about whether Ebola could actually end up as a terrorist agent here in this country. And so they said we better develop some drugs to have something in our back pocket should somebody try to use this virus to attack people. So both the Defense Department and the National Institutes of Health have pumped in more than $100 million to research and develop these drugs and to try to find something that will actually work against Ebola and related viruses.

INSKEEP: The Pentagon and other parts of the government are making a market for this drug or a drug?

HARRIS: Yeah, they will be the market. If - you know, they're saying to these companies if you make it, we'll buy it.

INSKEEP: Well, this is interesting because you said the U.S. government has spent $100 million because they think this could be a terrorist tool, it could be a weapon. Could Ebola actually be a very effective weapon?

HARRIS: Not a very effective weapon. It would certainly be terrifying. But it does not spread easily, which means that if you come in contact with it directly you might be at risk. But it's not into spread in an epidemic style. One person won't pass it on to the next because the only way you can get it is if someone is actually already showing symptoms. And so by then we have good enough public health service in this country that we would have those people in isolation and you wouldn't have a runaway disease the way we're seeing in Africa.

INSKEEP: OK, so what are the companies, the three companies that have decide to play, coming up with?

HARRIS: Well, there are three actually quite different approaches to this. One is actually very similar to other anti-viral drugs that are already on the market and this approach is being developed by a company called by BioCryst Pharmaceuticals. A second approach uses a completely different method - and it uses strands of genetic material that could actually interfere with the viruses own genetic material. This is a kind of far out idea and it's being developed by a Canadian company called Tekmira. And the third is a cocktail of custom tailored antibodies. And we've been hearing about this, right? Because this was the drug that was given to the two Americans who got sick. And now also has been given to a Spanish priest who got sick while in West Africa. And those antibodies are actually being produced in tobacco plants. And the hope is that produce enough of those from the plants, start to give them to people and see if they actually work. We don't actually know if they work.

INSKEEP: Well, you do have these three cases - is that just not enough to know if these things are effective?

HARRIS: Not at all. In fact, these drugs haven't even been tested for safety on human beings. Normally what you do first of all after you developed a drug in animals is you say OK, let's give it to healthy volunteers and see how it works out for them. And that testing hasn't even happened with these drugs. So these are very early stages of development. And once you get past the safety test, then you start looking at tests to see - determine - if they are effective or not.

INSKEEP: We've been talking about this a little bit on our air - could desperation speed up that process a little bit?

HARRIS: Absolutely. Not only does desperation speed up the process, but the risks and benefits change if you have somebody who's actually actively sick with the disease. And you can say well, it may be risky to give them a dose of this drug, but it could be riskier just to let them go on with the other treatments that they give that are sort of called supportive treatments - oxygen and so on. So the risk and benefits change.

INSKEEP: Richard, this is a counterintuitive question I suppose, but is it really necessary to have a drug in order to contain the spread of Ebola?

HARRIS: It's actually not necessary at all. In fact, there have been 30 previous outbreaks of this disease and they've all been controlled without a drug. This one has obviously gotten away from public health people the way that previous ones have not, but there are very clear practices for dealing with an outbreak like this. You just make sure the virus isn't spreading from one person to another with the protective gear and so on. And public health officials are actually concerned that all this talk about a drug will distract from the fact that the drug is not the necessary ingredient here. You need a lot more people on the ground working very carefully to control this outbreak where it is right now.

INSKEEP: Richard, thanks.

HARRIS: My pleasure.

INSKEEP: NPR's Richard Harris.