Alessandra Tomasi received her B.A. from Cornell University and is now a first year medical student.
Tropical diseases directly affect more than one billion people in the developing world each year . Neglected Tropical Diseases, or NTDs, are defined as chronic, debilitating infections that are especially endemic in regions of severe poverty and poor sanitation, and for which treatments and preventions remain largely overlooked . Conditions such as chagas, dengue, lymphatic filariasis, and schistosomiasis represent a small fraction of such infections, yet they account for millions of afflictions each year . Despite the staggering statistics, however, few effective treatments have been made available to plagued populations. Largely found in tropical communities with unsafe drinking water, poor sanitation, and substandard housing, these populations remain socially and medically marginalized on a global scale . In fact, each year only a small fraction of medicines introduced to market by multinational pharmaceutical companies are specifically intended for treatment of tropical diseases in the Third World, and minimal returns on investment have only contributed to keeping this distribution exceptionally low. As the translation of lab and clinical progress into the development of new treatments continues to be a slow and costly process, advancements in the field of tropical pathology thus remain largely unavailable to the poverty-stricken populations that need it most . This disparity in access to proper medical care ultimately imparts burdens not only on the health but also the economic development of susceptible low-income countries.
Much of the burden set by tropical diseases can be prevented with known technologies; however, drug companies have had little incentive to spend millions to develop the necessary drugs and bring them to markets that need it most. In fact, the past decade has only targeted 3.8% of the 756 new drugs approved in the US and Europe to treat diseases in the developing world . Additionally, in 2012, the US government allocated over $7 billion to global health programs; however, only 1.3% of this was invested in NTDs . As a result, millions of people each year, most of them in Third World tropical regions, die of curable and even preventable diseases simply because it is not cost-effective to properly treat them.
The low quality of medical infrastructure in developing nations, coupled with inadequate levels of foreign aid, has impacted poverty-stricken communities beyond the scope of health and medical care . Disease slows growth and intellectual development in children and adolescents, and impedes productivity for working adults. Quantitatively, the economic burden caused by NTDs is expressed through the loss of disability-adjusted life years (DALYs), or the years of healthy life lost as a result of disability or premature death. In total, the 17 categorized neglected tropical diseases collectively account for a loss of approximately 46-57 million DALYs .
To understand the burden of disease on a more fundamental level, consider the specific case of lymphatic filariasis. It has been estimated that this particular NTD, which mostly affects rural communities in India, causes each infected patient to lose about 11 years’ worth of productivity . This corresponds roughly to a loss of $50 per year per individual, equivalent to 15% of one’s income. In total, it has been estimated that India alone loses approximately $1 billion per year in GDP to lymphatic filariasis .
Similarly, the parasitic infection onchocerciasis exhibits analogous destructive economic effects on plagued populations . Particularly endemic in African nations, the NTD accounts for over one million cases of visual disability and blindness, and is the world’s second leading cause of infectious blinding . Its debilitating effects cause infected patients in rural areas to abandon work, thereby dramatically reducing agricultural output. In Africa alone, onchocerciasis is responsible for over 640,000 disability-adjusted life years (DALYs); worldwide, it is responsible for nearly 1.5 million .
Because NTDs impact communities that are already marginalized on a global scale, the additional economic strains they impart greatly inhibit these populations’ ability to move out of poverty . Sustainability efforts in developing nations continue to be stunted, and communities around the world remain unable to climb the economic pyramid. With almost one-sixth of the world’s population affected by the lack of access to proper medical care and to the resources necessary for prevention and treatment of tropical diseases, the consequences of NTDs transcend their direct impact on individual health. As a result, it is important to shift from viewing these diseases solely within the context of individual health, and instead towards a view that also includes global, social, and economic contexts. With tropical diseases disproportionately affecting the poorest of populations, NTD awareness must be integrated into a broader social agenda to increase advocacy and strengthen global aid. Expanding financial resources alone will not solve the issue. By diminishing opportunities to succeed, NTDs reinforce cycles of poverty among the world’s most disadvantaged populations. Improvements in infrastructure and drastic changes in regulatory authority as well as government spending are slowly beginning to improve the situation; however, there remains a lot to be done.
1. Vogel G. Tackling neglected diseases could offer more bang for the buck. Science. 2006 Feb 3;311(5761):592-3.
2. WHO: Global Burden Data 2004: DALYs by age, sex and cause for the year 2004 http://apps.who.int/ghodata/?vid=110001. (Accessed November 11, 2011).
3. Hotez PJ, Fenwick A, Savioli L et al. Rescuing the bottom billion through control of neglected tropical diseases. Lancet 2009; 373: 1570–75
4. U.S. Global Health Policy: Fact Sheet: The U.S. Government Response to Global Neglected Tropical Diseases. May 2012 http://www.kff.org/globalhealth/upload/7938-03.pdf
5. K.D. Ramaiah, P.K. Das, E. Michael and H. Guyatt. The Economic Burden of Lymphatic Filariasis in India. Parasitology Today. 2000; 16 (6); 251-253.
6. Seymour J, Kinder M, Benton B. “Controlling Onchocerciasis (River Blindness) in Sub-Saharan Africa,” in Case Studies in Global Health: Millions Saved. Sudbury, MA: Jones and Bartlett Publishers, 2007.
7. Christopher J. L. Murray and Alan D. Lopez, The Global Burden of Disease, Harvard University Press, 1996.
8. Frew SE, Liu VY, Singer PA. "A business plan to help the 'global South' in its fight against neglected diseases." Health Aff (Millwood). 2009 Nov-Dec;28(6):1760-73