At a glance
- Neglected tropical diseases (NTDs) affect 1 billion people worldwide, and the poorest and most vulnerable communities suffer the most.
- While effective treatment and control methods are available, more investments are needed in drug delivery and diagnostic tools that will improve disease mapping and surveillance.
- We work with our partners to develop and deliver new tools to address tropical diseases affecting neglected populations.
- We focus on diseases that present the greatest opportunity for elimination or eradication, and we make use of donated drugs. We also accelerate progress by supporting public-health surveillance, vector control, and mass administration of drugs against multiple diseases.
The latest updates on neglected tropical diseases
Battling NTDs is a priority for our foundation, and we make sure our investments complement the work of donor governments and developing countries, which provide most of the funding to combat these diseases.
We concentrate on areas where existing funds are scarce, where our support can have a catalytic effect, and where we are better positioned than others to assume risks. To date, our team has committed more than US$1.02 billion in grants to organizations that are developing new tools and new delivery methods to make them widely available. We also advocate for increased international funding to support these efforts.
Many tropical diseases could be considered neglected, so we target our investments toward diseases that are large in scale and severity, that impose significant social and economic burdens on developing countries, and that have the greatest likelihood of elimination or eradication through strategic, feasible interventions.
We currently target the 10 NTDs specified in the London Declaration on Neglected Tropical Diseases, and we vary our approach based on the unique challenges of each disease.
Areas of focus
While we are targeting 10 NTDs, most of our funding goes toward the seven that present the greatest opportunity for elimination or eradication. We support the development and delivery of new drugs, vaccines, diagnostics, vector-control tools, and program approaches, and we tailor our investments to each disease.
One high-opportunity target is onchocerciasis (river blindness), which is caused by a parasitic worm transmitted to humans by black fly bites. About 37 million people are infected, primarily in Africa, but mass distribution of the donated drug ivermectin has helped eliminate the disease in many parts of Africa and South America.
But because this drug kills only worm larvae, adult worms can reproduce and spread the disease. As a result, people infected with the disease must repeat treatment up to twice a year for a decade or more. Another challenge is that millions of people in West Africa are infected by eye worm (also known as loa loa), which makes them unable to tolerate ivermectin. For these people, there is no effective treatment for river blindness.
Where possible, we are working to help eliminate river blindness with current drugs. We also support efforts to develop new treatments, including new methods of controlling disease transmission and a new drug that would attack adult worms and could be used for patients with eye worm.
We are also targeting lymphatic filariasis, a mosquito-transmitted disease caused by parasitic worms. An estimated 120 million people are infected, and one in six people globally is at risk of this disabling disease.
Thanks to efforts to reach remote communities, more than 600 million people have received lymphatic filariasis treatment. To reach the rest, we need to understand where affected people live, so we invest in surveillance and precision mapping. Until recently, the number of people at risk of lymphatic filariasis in Ethiopia had been estimated at 30 million; mapping showed that the estimate should be reduced to 6 million—saving hundreds of millions of dollars’ worth of drugs.
Meanwhile, researchers are conducting clinical trials on the administration of lymphatic filariasis and onchocerciasis drugs in different combinations, dosages, and frequency to achieve better results.
The other high-opportunity diseases we target are visceral leishmaniasis (black fever), soil-transmitted helminthiases (hookworm, roundworm, and whipworm), schistosomiasis (snail fever), dracunculiasis (Guinea worm disease), and human African trypanosomiasis (known as HAT or sleeping sickness).
We support efforts to develop new ways to attack multiple infectious diseases at the same time in a coordinated and integrated fashion. We focus on three main areas:
- Mass drug administration. We support coordinated efforts in areas with a prevalence of several infectious diseases that can be treated with the same drugs or a similar schedule of treatments. This includes obtaining donations to support large-scale drug administration programs. Five of our target NTDs can be controlled in this way, including river blindness, lymphatic filariasis, soil-transmitted helminths, schistosomiasis, and trachoma.
- Public health surveillance. Good data are crucial—such as data on where a disease is prevalent in humans and where it’s found in mosquitoes, flies, worms, or other vectors. Since these data are lacking for many NTDs, we look for shared approaches to sample collection and processing, data aggregation, and the design of surveillance systems and precision mapping that can pinpoint at-risk populations. Four of our target NTDs—sleeping sickness, leishmaniasis, Chagas disease, and leprosy—can be controlled by screening at-risk populations and treating infected individuals.
- Vector control. Most NTDs are caused or spread by insects or worms, which are costly and difficult to control. But control measures are similar for all of these vectors, so we can be more effective by coordinating multiple efforts. To improve coverage, we support the development of a framework for cross-disease coordination, including the integration of NTD and non-NTD tools. For instance, the same diagnostic test could be used for sleeping sickness and malaria, since both diseases look similar in the early stages.
Our 10 target NTDs are:
- Chagas disease
- Dracunculiasis (Guinea worm disease)*
- Human African trypanosomiasis (sleeping sickness)*
- Visceral leishmaniasis (black fever)*
- Lymphatic filariasis (elephantiasis)*
- Onchocerciasis (river blindness)*
- Schistosomiasis (snail fever)*
- Soil-transmitted helminthiases (hookworm, roundworm, whipworm)*
Why focus on NTDs?
More than 1 billion people in developing countries suffer from infectious diseases that attract little donor funding, largely because those diseases are rare in wealthier countries.
These NTDs cause anemia and blindness, stunt children’s growth, lead to cognitive impairments, complicate pregnancies, and result in thousands of deaths each year. People living in extreme poverty often suffer from more than one of these diseases at the same time, which affects their ability to make a living and move out of poverty.
Because this public health burden affects dozens of poor countries, we must address NTDs if countries are to meet their targets under the United Nations Sustainable Development Goals. Today, we have safe, effective treatments and control methods to fight some NTDs. The challenge is reaching poor and hard-to-reach communities where people have little access to health care and recent successful efforts give us hope that strategic, innovative, collaborative, and sustained action can control, eliminate, or even eradicate some of the these diseases.
In 2015, cases of dracunculiasis (Guinea worm disease) fell to a historic low of 22, contained in just four countries. While 120 million people are infected with mosquito-borne lymphatic filariasis (elephantiasis), more than 5 billion treatments have been delivered since 2000.
The progress against lymphatic filariasis came as a result of a global alliance that delivered drugs donated by Merck, Eisai, and GlaxoSmithKline. Despite limited economic incentives, those pharmaceutical companies have increased their donations and supported research and development on NTDs.
Growing resolve within the public and private sectors can accelerate progress even further. In January 2012, the foundation; 13 pharmaceutical companies; the governments of the United States, United Kingdom, and United Arab Emirates; the World Bank; and other global health organizations signed the London Declaration on Neglected Tropical Diseases, launching a global push to control, eliminate, or eradicate 10 NTDs by the end of the decade. This has since shaped the framework for our strategy to fight NTDs.