Why should we fund research on neglected tropical diseases?
This month, the eLife Podcast is focusing on tropical diseases in this edition of the programme. But why are they neglected, and why shouldn’t they be? Chris Smith speaks to eLife Senior editor and the University of Toronto's Professor of Global Health, Prabhat Jha...
Prabhat - When we talk about neglected tropical diseases, they represent a grab bag. It’s actually quite different parasitic or vector diseases which actually are quite different in different settings – African trypanosomiasis, schistosomiasis, leishmaniasis, leprosy, dengue, rabies, things like hookworm disease. What is common to them, they actually don’t kill in very large numbers but they cause a substantial amount of disability. The second thing that unites these diseases, they are among the most heavily concentrated in the poorest parts of the world. Now, that’s important because getting rid of them has double challenges. You're working in difficult places of the world. The upside is control of these diseases. It’s probably one of the best pro-poor things the world could do in poor countries.
Chris - Really, the spinoff of what you're saying is, if we intervene in these countries, a) the money goes further because they're poorer countries and things turn a bit more cheaper – notwithstanding the challenges but b) there's a huge economic benefit because of the way these diseases cause chronic disability.
Prabhat - Absolutely. Most of these conditions – take leprosy, which is still quite common in India is a big cause of poverty of the household. Visceral leishmaniasis which again is in many parts of India causes lifelong disability in those affected. These are eminently treatable and we have had successes. We have been able to get rid of Guinea worm in Africa and the odds is on its way to being eradicated. There are targets. The World Health Organisation has set targets for getting rid of leprosy, trachoma, and a few of these other conditions. It’s going to be difficult because as we know from the experience in eliminating polio, when you start out in a campaign to get rid of these diseases. The first few cases you detect and treat are generally easy to find and cheaper but as you go along, they become harder to detect and therefore, they need more resources and they need newer science as well.
Chris - It’s also a moving target though, because with polio and things like that, we have seen cultural barriers to eradication. We’ve seen walls so we’ve seen a lot of human factors intervening which actually have thrown a huge spanner in the works and we would probably be a lot further along. It wasn’t the science. It wasn’t actually the funding that held the process up. It was other people.
Prabhat - Absolutely and those are part of the challenges of working in these poor countries. But the good news I think is the world made progress on polio because it put money into it and it invested in moving from oral polio to injected polio. There is good scientific thinking behind that because the injected polio was less likely to cause disease in a way that oral polio would. We know that even earlier on from the smallpox eradication that it required a new technology which was basically using ring vaccination, finding a case of smallpox and vaccinating everyone around that. That scientific breakthrough of using ring vaccination was exactly what the world has tested in the latest Ebola vaccine. So the key there is that as these targets get met, it will need a lot more money and the last mile is always the more expensive.
Chris - Does it not come down to human population? We’re invading more virgin territory where these diseases are endemic in nature and it’s more likely we’re going to see spill over into humans. So until we get to the bottom of the population problem, we’re really ignoring the elephant in the room.
Prabhat - Well, I think they're related but not causally related. But the positive news is that if you look at areas where there is an increasing urban concentration and you’ve got urban infrastructure, you can actually have clinics then it is in some ways easier to control these.
Chris - Ironically, people have said that with Ebola, it was people coming across the border to come to these towns where there were albeit – not terribly good – but there were medical facilities and this was actually helping to spread the outbreak.
Prabhat - That’s right and the other factors which is important in Ebola was the burial practices where you had to hug the body goodbye. Their response to it was late but very crude isolation strategies that were brought in were effective.
Chris - So we need better resources. We need more science thrown at this in order to be more crafty and clever as time goes on. But will people pay for it because the harsh reality is, Ebola, the vaccines we now have something like 7 different vaccines in trials at various stages of development or more for Ebola? Now they're not rocket science. Those vaccines have been made using fairly mundane techniques actually that we’ve had for decades in some cases. Yet, no one wanted to make them and deploy them because they didn’t think Ebola was a country’s problem that had the capacity to make those vaccines.
Prabhat - In the short or medium term, it’s in everybody’s interest to stamp out epidemics where they occur because it spreads. But I would argue that public funding of science which has really decreased since the 1970s really needs to be back on the same level because that science creates products and tools that you can use to fight epidemics. The private sector won't take care of these epidemics. They have no incentive to.