Neglected Tropical Diseases

Neglected tropical diseases (NTDs) are a group of parasitic, bacterial, viral, and fungal infections that predominantly affect populations living in poverty in tropical and subtropical regions. The World Health Organization recognizes approximately 20 NTDs, including schistosomiasis, lymphatic filariasis, trachoma, leishmaniasis, African sleeping sickness, Chagas disease, and soil-transmitted helminths. Together they affect over a billion people, causing disability, disfigurement, and death on a scale comparable to HIV/AIDS, tuberculosis, and malaria — yet they receive a small fraction of the global drug discovery and public health investment directed at those diseases.

The term 'neglected' is a precise description of a market failure, not a characterization of scientific difficulty. The biology of most NTDs is tractable — their causative agents have been characterized, their life cycles are understood, and some respond to existing drugs. What is lacking is the financial incentive that drives pharmaceutical investment: NTD patients are predominantly poor, concentrated in low-income countries, and cannot pay prices that would justify commercial development costs. The result is that effective vaccines and treatments for diseases affecting hundreds of millions of people are unavailable not because the science is intractable but because the economic structure of pharmaceutical research does not reward solving them.

The Drugs for Neglected Diseases initiative (DNDi), founded in 2003, represents an alternative model: a not-for-profit drug development organization that partners with public institutions, philanthropies, and endemic-country manufacturers to develop and deliver drugs at affordable prices. Its track record — developing six new treatments for sleeping sickness, leishmaniasis, Chagas disease, and hepatitis C at a fraction of commercial development costs — provides the clearest evidence that the neglect of these diseases is structural rather than scientific. See also global health equity and access to medicines.