Neglected tropical diseases have been getting a bit of press recently, possibly because it’s been a slow news week or two in the world of global health. Neglected Tropical Diseases (NTDs) are so named because they’re precisely that: generally ignored by funders, scientists, advocacy organizations, and governments. They are often endemic in developing countries, where media attention is scarce and profit margins small for drug and vaccine development. It doesn’t help that many of these diseases are “unsexy” or “icky” (don’t Google image search guinea worm unless you have a strong stomach) or a mouthful (leishmaniasis, onchocerciasis, or schistosomiasis). All the same, nearly 1 in 6 people worldwide suffers from an NTD, including 500 million children. NTDs can cause death, disfigurement, blindness, and developmental disability, which perpetuate cycles of poverty. For a bit more on NTDs, check out a recent 7-minute spot from PBS News Hour or head over to the Global Network for Neglected Tropical Diseases.
Current treatment and prevention options for many NTDs require a single, preventative dose yearly (or every six months), such as that for lymphatic filariasis, commonly known as elephantiasis, or massive swelling of the limbs and/or genitals, and onchocerciasis, also known as river blindness. As the Global Network for NTDs points out, many of the required drugs cost less than 50 cents per person per year: I was surprised to learn that Big Pharma donates a lot of drugs for NTDs, which keeps costs down (see page 15 of the WHO roadmap linked above). In many cases, however, the treatment options are scarce, ineffective, or even toxic. As The Guardian reported, the Gates Foundation met with 13 pharmaceutical companies, donor governments, multilateral officials, the Global Network for NTDs, and governments of affected countries to discuss NTDs at a summit in London last month. The pharma companies agreed to donate additional meds and work on new ones, with an emphasis on public-private partnerships, to eradicate ten targeted NTDs by 2020, including Chagas and river blindness. This is a good first step. Additionally, vaccines are few and far between. The Infectious Disease Research Institute (IDRI) announced this week that it had begun Phase I trials for a vaccine for visceral leishmaniasis, which is known as the “parasitic version of HIV/AIDS” and has a 90% mortality rate.
It is heartening to hear that researchers and pharmaceuticals are paying some attention to NTDs, but of course, it’s never quite enough. As the WHO points out in its 2012 Roadmap (PDF), NTD prevention, eradication, and control require efforts far beyond the distribution of pills, vaccines, and other “traditional” global health activities: vast development-related improvements, such as updated sanitation, clean water, and better living conditions, are key. Changes like these are slow and expensive, especially when 900 million people do not have access to safe water and 2.5 billion do not have adequate sanitation (WHO, above). As Peter Hotez of the Sabin Vaccine Institute details, NTDs are a “poverty trap,” lessening one’s ability to go to school or work. Hookworm, which affects at least 600 million people, “stunts physical growth and dramatically reduces intelligence and memory in children, reducing future wages by almost 50 percent.” NTDs have economic consequences beyond the personal (which would be bad enough): imagine how much stronger developing economies could be if those 600-million-plus-people were learning and working at the top of their abilities (unemployment and inadequate educational opportunities aside). The causes and effects of NTDs go far beyond health and healthcare.
Unfortunately, the London Declaration goals seem overly sanguine, given the current economic climate and donor fatigue, and clinical trials take a very long time. Worryingly, as IDRI points out in its announcement for Stage I leishmaniasis trials, “the geographical range for leishmaniasis is expanding. Spurred on by global warming, mass migration and rapid urbanization, cases are being reported in previously unaffected areas.” This applies to other neglected tropical diseases as well: our world grows smaller every day, it seems–and warmer. That, perhaps, is one very cynical silver lining: as the footprint of NTDs expands with globalization and global warming, affecting wealthier countries, we may see an increased demand for the development of new treatments and vaccines and more aggressive preventative measures. Until that happens, we’ll have to keep our fingers crossed that scientists, pharmaceuticals, host and donor countries, and global health and development non-profits can keep rolling back NTDs, slowly but surely.
Header photo is of the freshwater snail oncomelania hupensis, which carries and transmits the parasite that causes schistosomiasis. By Fred A. Lewis, Yung-san Liang, Nithya Raghavan & Matty Knight, CC-BY-2.5, via Wikimedia Commons.
