Elephantiasis is the result of a neglected tropical disease that overwhelmingly afflicts poor people. Credit: Maggie Steber/The Washington Post/Getty

As a physician in Tanzania, Upendo Mwingira has little to offer people suffering from elephantiasis, an incurable condition characterized by swollen, wrinkled limbs. “When they enter the clinic, they smell, their wounds are oozing and, as a doctor, the best thing I can do is help them accept their situation,” says Mwingira, who directs the neglected-tropical-diseases division of Tanzania’s Ministry of Health in Dar es Salaam. 

But patients with the condition have become an increasingly rare sight in her clinics. A global effort to curb the disease that results in elephantiasis, called lymphatic filariasis, has sent the number of new cases plummeting in Tanzania and at least 18 other countries. Seven more nations, including Cambodia and Sri Lanka, have in the past year eliminated it. The prevalences of other neglected tropical diseases that affect the world’s poorest people have been dropping too. But health officials are not resting on their laurels. Even as they celebrate these victories, they are meeting this week in Geneva, Switzerland, to ramp up their efforts to combat the diseases.

They will make plans to treat the hundreds of millions of people who still need it, and to come up with ways to reach communities located far from health services. Several groups will also announce extra funding to fight neglected diseases. The Bill & Melinda Gates Foundation in Seattle, Washington, plans to commit another US$335 million to the cause, and the UK Department for International Development (DFID) will contribute £360 million (US$450 million).

Neglected tropical diseases affect roughly 1 billion people worldwide and kill about 534,000 each year, according to the US Centers for Disease Control and Prevention (CDC). But drug companies and science agencies in rich countries tend to ignore these maladies because they almost exclusively afflict the world’s poorest people. The Gates Foundation threw its energy into fighting these illnesses starting in 1999, when it realized that a relatively small investment could dramatically improve millions of lives, says cofounder Bill Gates. It estimates that a package to treat or prevent several neglected diseases costs around $0.50 per person.

Better together

Gates told Nature that recent successes are the result of global partnerships between governments, companies and nongovernmental organizations that have formed over the past decade. Multiple groups, including the Gates Foundation, the US Agency for International Development (USAID) and the DFID, signed a global agreement in 2012 called the London Declaration on Neglected Tropical Diseases to eliminate or reduce the prevalence of ten neglected diseases by 2020.

Five of the targeted diseases, such as lymphatic filariasis and leprosy, can be prevented with drugs. Treatments are the only option for the other five, including visceral leishmaniasis (or kala-azar) — a potentially fatal disease spread by sandflies — and river blindness.

Pharmaceutical companies have been donating drugs for these illnesses for more than a decade, but the lack of reliable distribution systems has often kept people from receiving treatment.

Since 2006, USAID has been trying to fix that issue. One way is by funding nongovernmental organizations that ensure community workers in remote towns have the tools that they need to treat the ill. As a result, more than 1.6 billion treatments, worth an estimated US$11.1 billion, have gone to 31 countries.

More than 300 million people who required preventive treatments for at least one neglected disease five years ago no longer need them because transmission has dramatically slowed, thanks to mass drug administration, according to the World Health Organization. Cases of treatable diseases are dropping, too: since 2005, kala-azar has decreased by 82% in India, Nepal and Bangladesh. Sleeping sickness has plummeted in Africa by 89% since 2000.

Rough road ahead

But to stamp out the ten conditions listed on the London Declaration, millions of people around the world still require treatments and cures. Scientists could help to speed up progress by considering the challenges in places where neglected diseases occur, says David Molyneux, a parasitologist at the Liverpool School of Tropical Medicine, UK. For example, strategies to train and pay health workers to spot early signs of infection might save more lives than sequencing parasitic genomes. 

And simple tests for detecting several neglected diseases would also be advantageous for people around the world, says Tom Frieden, a former CDC director.

All of this work requires money, which might be a problem if the US Congress approves President Donald Trump's request to cut the budget of the state department and USAID by 37%. “Any drop of funding in this area will lead to more death and more suffering,” Gates says.

However, the partnerships formed over the past five years provide a kind of safety net. And the fact that the United Nations chose alleviation of poverty as its first Sustainable Development Goal — a list of targets for 2016–30 made by global leaders to improve the world — gives researchers such as Molyneux hope. “Unless you are going to do something about these diseases, people in poverty will continue to be constrained by poverty.”