Most of our funding goes toward addressing nine diseases that present the greatest opportunity for control, elimination, or eradication. With several of these diseases, large-scale interventions have made good progress but more needs to be done. We support the development and delivery of new drugs, vaccines, diagnostics, vector-control tools, and program approaches, tailoring our investments to each disease.
Our investments focus on the development of new treatments, tools, and control measures and on ways to make them broadly available.
One high-opportunity target is onchocerciasis (river blindness), which is caused by a parasitic worm transmitted to humans by black fly bites. Some 18 million people are infected, primarily in Africa, but mass distribution of the donated drug ivermectin has helped to eliminate the disease in many parts of Africa and South America.
Ivermectin kills only worm larvae, however, leaving adult worms unaffected and allowing them to produce more larvae that can spread disease. This means that people infected with the disease must repeat drug treatment annually or even 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 and leaves them with no effective treatment for river blindness.
We are working to help eliminate onchocerciasis with current drugs where that is possible. We also support efforts to develop new treatments that could be more effective and more widely used. These include new methods of controlling disease transmission and a new drug that would attack adult worms and could be used safely where eye worm is prevalent.
Another target disease is dengue, a mosquito-borne viral illness. Its incidence has increased 30-fold worldwide since the 1960s, and an estimated 50 million people are infected each year. There is no effective treatment, and current methods of controlling transmission are costly and often ineffective because they are used too late.
Dengue is a high-opportunity target because several potential vaccines are in development. We are supporting preparations to deploy a safe and affordable vaccine when it becomes available. Meanwhile, we are investing in the development of novel mosquito-control methods to prevent outbreaks. We are also funding work on new ways to detect or even predict dengue outbreaks early enough for transmission controls to succeed.
The other high-opportunity diseases that we target are Japanese encephalitis, human papillomavirus (HPV), visceral leishmaniasis (black fever), hookworm disease, dracunculiasis (guinea worm), lymphatic filariasis (elephantiasis), and human African trypanosomiasis (sleeping sickness).
We support efforts to develop new ways to attack multiple infectious diseases at the same time, in a coordinated and integrated fashion. These efforts include three main areas of focus:
Mass drug administration. In areas where several infectious diseases are prevalent and can be treated with the same drugs or a similar schedule of drug treatments, we support efforts to coordinate the various components of large-scale drug administration programs, such as obtaining commitments to donate drugs.
A Médecins Sans Frontières (Doctors Without Borders) screening and treatment site for neglected tropical diseases in rural Uganda.
- Public-health surveillance. In fighting infectious diseases, good data is crucial—such as data on where a disease is prevalent in humans and in the mosquitoes, flies, worms, or other vectors that transmit it. Such data is lacking for many neglected diseases. We are seeking solutions such as shared approaches to sample collection and processing, data aggregation, and the design of efficient surveillance systems.
- Vector control. Most neglected infectious diseases 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 better cross-disease coordination would improve the efficiency and effectiveness of the various vector-control efforts. We support the development of a framework for cross-disease coordination to improve the coverage and impact of vector-control measures.
We are currently winding down our work on three diseases: rabies, trachoma, and cysticercosis (tapeworm infection). Several of our partners are leading efforts to combat these diseases, using available treatments and tools. Our final investments are aiding their work.
To improve prospects for curbing six newly targeted diseases—ascaris, trichuris, hookworm, schistosomiasis, Buruli ulcer, and Chagas disease—we are investing in research to better understand their transmission patterns and what tools or interventions are needed to fight them.