Neglected tropical diseases (NTDs) are a diverse group of tropical infections which are common in low-income populations in developing regions of Africa, Asia, and the Americas. They are caused by a variety of pathogens such as viruses, bacteria, protozoa and parasitic worms (helminths). These diseases are contrasted with the big three infectious diseases (HIV/AIDS, tuberculosis, and malaria), which generally receive greater treatment and research funding. In sub-Saharan Africa, the effect of these diseases as a group is comparable to malaria and tuberculosis. NTD co-infection can also make HIV/AIDS and tuberculosis more deadly.
In some cases, the treatments are relatively inexpensive. For example, the treatment for schistosomiasis is US$0.20 per child per year. Nevertheless, in 2010 it was estimated that control of neglected diseases would require funding of between US$2 billion and US$3 billion over the subsequent five to seven years. Some pharmaceutical companies have committed to donating all the drug therapies required, and mass drug administration (for example, mass deworming) has been successfully accomplished in several countries. However, preventive measures are often more accessible in the developed world, but not universally available in poorer areas.
Within developed countries, neglected tropical diseases affect the very poorest in society. In the United States, there are up to 1.46 million families including 2.8 million children living on less than two dollars a day. In countries such as these, the burdens of neglected tropical diseases are often overshadowed by other public health issues. However, many of the same issues put populations at risk in developed as developing nations. For example, other problems can stem from poverty which expose individuals to the vectors of these disease, such as lack of adequate housing.
Twenty neglected tropical diseases are prioritized by the World Health Organization (WHO), though other organizations define NTDs differently. Chromoblastomycosis and other deep mycoses, scabies and other ectoparasites and snakebite envenomation were added to the list in 2017. These diseases are common in 149 countries, affecting more than 1.4 billion people (including more than 500 million children) and costing developing economies billions of dollars every year. They resulted in 142,000 deaths in 2013—down from 204,000 deaths in 1990. Of these 20, two were targeted for eradication (dracunculiasis (guinea-worm disease) by 2015 and yaws by 2020), and four for elimination (blinding trachoma, human African trypanosomiasis, leprosy, and lymphatic filariasis) by 2020.
According to the World Health Organization (2018), so-called Neglected Tropical Diseases (NTDs) affect more than one billion people and cost developing economies billions of dollars every year. Populations living in poverty, without adequate sanitation and in close contact with infectious vectors such as livestock are most affected by these communicable illnesses, which prevail in tropical conditions. To complicate matters, diseases like measles and tuberculosis, which were nearly eradicated a century ago, are again on the rise. And more common, eminently treatable infectious diseases – norovirus and flu, for example – are responsible for thousands of preventable deaths each year.