Rescuing the 'Bottom Billion' Through Control of the Neglected Tropical Diseases

(May 2010) With Millennium Development Goal 6, the international community pledged to “combat HIV/AIDS, malaria, and other diseases” throughout the world. Worldwide, 1.4 billion people are infected with one or more of these less-known “other diseases.” They come from the poorest of the poor who live on $1.25 or less per day, mostly on farms and in urban slums of the developing world. While these diseases have serious adverse effects on communities and exacerbate poverty, there are limited resources available for their research and treatment. Peter Hotez, distinguished research professor and chair of the Department of Microbiology, Immunology, and Tropical Medicine at The George Washington University, and president of the Sabin Vaccine Institute, discussed neglected tropical diseases (NTDs) and their impact on developing countries at a recent PRB policy seminar. In what way do these diseases affect poor countries and what are some of the possible options for their control and elimination?

The most common NTDs affect hundreds of millions of individuals and are the most prevalent infections among the poorest 1 billion people. Some of these neglected diseases include ascariasis (roundworm), which affects 807 million people; trichuriasis (whipworm) with 604 million infections; and hookworm with about 576 million people infected worldwide. The NTDs have serious consequences in the developing world. They promote and reinforce poverty and can be a source of stigma because people with NTDs have a decreased capacity to work. Therefore, controlling or eliminating these diseases is crucial to poverty eradication. According to one estimate, the economy in India alone loses almost $1 billion annually as a result of reduced agricultural productivity caused by the side effects of chronic and disabling diseases. In addition to hurting the labor force and productivity, some of the diseases can impair intellectual and physical development in children and cause serious adverse pregnancy outcomes. Up to one-third of pregnant women are infected with hookworm in sub-Saharan Africa, which can lead to severe anemia and increase the chances of maternal and perinatal child mortality. Despite the large number of affected people and the severe side effects of NTDs, it is difficult to capture the attention of policymakers. “We do not have a good elevator speech for NTDs. Policymakers like numbers and we do not have good numbers yet,” said Hotez.

The prevalence of NTDs in the Muslim world, as well as in nuclear states, has strong geopolitical and foreign policy implications for the United States. Forty percent of the tropical disease burden falls on countries that are members of the Organization of the Islamic Conference. In addition, 25 percent to 30 percent of hookworm, ascariasis, and lymphatic filariasis (eye worm) infections occur in India, China, Pakistan, North Korea, Iran, and Syria—countries either in possession of nuclear weapons or desiring nuclear capabilities. The same countries also represent 50 percent of leprosy and trachoma cases worldwide. The Obama administration has put considerable emphasis on showing goodwill toward these countries, taking advantage of the opportunity for vaccine diplomacy. According to Hotez, an ambitious vaccine development and distribution program focused on tropical infectious diseases prevalent in these regions might foster a spirit of cooperation and demonstrate compassion on the part of the United States.

Global Disease Research and Development Investment, 2008

Disease Amount (US$) Percent
HIV/AIDS 1,215,841,708 39.3
Malaria 565,985,827 18.3
Tuberculosis 467,538,635 15.1
Kinetoplastids 145,676,517 4.7
Diarrhoeal diseases 138,159,527 4.5
Dengue 132,470,770 4.3
Bacterial pneumonia & meningitis 96,071,934 3.1
Helminth infections (worms and flukes) 69,518,274 2.2
Salmonella infections 41,079,293 1.3
Leprosy 10,073,184 0.3
Rheumatic fever 2,268,099 0.1
Trachoma 2,225,330 0.1
Buruli ulcer 2,140,303 0.1
Platform technologies 16,569,978 0.5
Core funding of a multidisease R&D organization 110,403,054 3.6
Unspecified disease 78,179,894 2.5
Total 3,094,202,327 100

Source: The George Institute for International Health, Neglected Disease Research & Development: New Times, New Trends (December 2009), accessed at, on May 10, 2010.

NTDs did not appear on the public agenda until 2005 and they command a small portion of the global investment in research and development (R&D). Funding is highly concentrated on specific diseases; in 2008, about 73 percent of global R&D expenditures went to support HIV/AIDS, malaria, and tuberculosis research. The $2.2 billion invested in the “big three” sharply contrasts with the $840 million spent on the other major NTDs (see table). There is reason for optimism, however. Several countries have seen successes with mass drug administration, where drugs are given to an entire population in high-infection areas, regardless of people’s disease status. Great reductions in cost come from eliminating the expense of diagnosis and treating everyone as if they were infected. Various governments have applied this method successfully—Zanzibar and the South Pacific radically reduced the prevalence of lymphatic filariasis in the early 2000s, and Egypt successfully fought schistosomiasis (bilharzia or snail fever) during the 1990s.

Hotez highlighted another cost-effective and viable option for treatment, the Rapid Impact Package, which includes a combination of drugs and targets seven major NTDs, including hookworm, lymphatic filariasis, and onchocerciasis (river blindness). Together with delivery and equipment costs, training of personnel, and monitoring and evaluation expenses, these drugs cost 50 cents for one person for a whole year, making this one of the “best buys” in public health.

Kata Fustos is an intern in the Communications department at the Population Reference Bureau.