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.
our investments focus on the development of new treatments, tools, and control measures, and on ways to make them widely available.
one high-opportunity target is onchocerciasis (river blindness), which is caused by a parasitic worm transmitted to humans by black fly bites. approximately 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.
however, 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, dracunculiasis (guinea worm), and human african trypanosomiasis (known as hat or sleeping sickness).