Neglected tropical diseases
Neglected tropical diseases (NTDs) are a diverse group of conditions1 caused by a variety of pathogens (including viruses, bacteria, parasites, fungi and toxins) and associated with devastating health, social and economic consequences. NTDs are mainly prevalent among impoverished communities in tropical areas, although some have a much larger geographical distribution. It is estimated that NTDs affect more than 1 billion people, while the number of people requiring NTD interventions (both preventive and curative) is 1.6 billion.
The epidemiology of NTDs is complex and often related to environmental conditions. Many of them are vector-borne, have animal reservoirs and are associated with complex life cycles. All these factors make their public-health control challenging.
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1. NTDs include: Buruli ulcer; Chagas disease; dengue and chikungunya; dracunculiasis; echinococcosis; foodborne trematodiases; human African trypanosomiasis; leishmaniasis; leprosy; lymphatic filariasis; mycetoma, chromoblastomycosis and other deep mycoses; noma; onchocerciasis; rabies; scabies and other ectoparasitoses; schistosomiasis; soil-transmitted helminthiases; snakebite envenoming; taeniasis/cysticercosis; trachoma; and yaws.
WHO estimates that over 1.6 billion of the world’s population should be targeted by prevention and treatment activities for at least one of these diseases, every year.
In addition to significant mortality and morbidity - approximately 200,000 deaths and 19 million disability adjusted life years (DALYs) lost annually, NTDs cost developing communities the equivalent of billions of United States dollars each year in direct health costs, loss of productivity and reduced socioeconomic and educational attainment. They are also responsible for other consequences such as disability, stigmatization, social exclusion and discrimination and place considerable financial strain on patients and their families.
In spite of this, NTDs have historically ranked very low and almost absent from the global health policy agenda – only to gain recognition in 2015 with the Sustainable Development Goals (SDG target 3.3). SDG3 can therefore be achieved only if the NTD goals are met but, because interventions to tackle NTDs are widely cross-sectoral, increasing their global prioritization can in fact catalyze progress to achieve all SDGs.
WHO’s action to control, prevent, eliminate and eradicate NTDs is guided by the NTD road map for 2021-2030, that moves away from vertical disease programmes to integrated cross-cutting approaches. The aim is to facilitate the coordinated scale-up of key interventions through public health approaches such as preventive chemotherapy, individual case management, vector control, veterinary public health and water, sanitation and hygiene (WASH).
The overarching 2030 global targets include a 90% reduction in the number of people requiring treatment for NTDs; a 75% reduction in DALYs related to NTDs; at least 100 countries eliminating at least one NTD; and the eradication of two diseases (dracunculiasis and yaws).
Additional cross-cutting targets focus on integrated approaches, multisectoral coordination, universal health coverage and country ownership, while a further set of targets has been devised to measure progress against each disease.