âNeglected tropical diseasesâ (NTDs, for short) is a name for a collection of diseases, coined in the early 2000s, that have received growing attention within global health. As Koplan et al. describe, â(G)lobal health is derived from public health and international health, which, in turn, evolved from hygiene and tropical medicineâ (2009, p. 1993). NTDs have gone full circle, originally being largely diseases of hygiene and tropical medicine, to be sidelined on many levels (scientifically, financially, socially, and politically), and now they are of central interest within global health. These 20 diseases are listed by the World Health Organization (WHO) as shown in Box 1.1, in alphabetical order (WHO, 2016a).
Box 1.1 WHO list of NTDs
- Buruli ulcer
- Chagas disease
- Dengue and chikungunya
- Dracunculiasis (guinea-worm disease)
- Echinococcosis
- Foodborne trematodiases
- Human African trypanosomiasis (sleeping sickness)
- Leishmaniasis
- Leprosy (Hansenâs disease)
- Lymphatic filariasis
- Mycetoma, chromoblastomycosis and other deep mycoses
- Onchocerciasis (river blindness)
- Rabies
- Scabies and other ectoparasites
- Schistosomiasis
- Snakebite envenoming
- Soil-transmitted helminthiases
- Taeniasis/cysticercosis
- Trachoma
- Yaws (endemic treponematosis)
The WHO groups NTDs on the basis of agreed common characteristics â just as was done for tropical diseases in former times, but the methods behind the standardising of this grouping are far from straightforward. The various lists of NTDs attest to this difficulty, and I will go into more detail about lists and the politics of categorisation in Chapter 2. For now, it is worth remarking that the 20 NTDs listed by the WHO tend to be the most well acknowledged, and other organisations draw a shorter selection from this list. This is especially the case for organisations running programmes that require direct interventions.3
Returning to the WHOâs list of 20, the diseases included form a mixed bag of not very pronounceable names, some of which may be familiar to western audiences. Leprosy and rabies are ancient diseases of the poor (Little, 2007). While travellers can vaccinate against rabies, they may also come across chikungunya, for which there is no vaccine. Still, others may pick up one of the other non-descript âtropical diseasesâ from a hot country, although some tropical diseases never were especially tropical, discussed in Chapter 2. Rather than being rare and exotic, NTDs are in fact a common affliction â not only a threat to travellers. They are often debilitating and sometimes deadly for the majority of the worldâs poorest people. The scale of NTDs for the global poor is large, with one or more NTDs affecting over a billion people in 149 countries (World Health Organization. Department of Control of Neglected Tropical Diseases 2017). Therefore, despite the label of neglect, and perhaps unfamiliarity in the western world, these diseases are widespread and pervasive.
Progress is being made to tackle NTDs, with âBig Pharmaâ mostly behind the over $5 billion in drugs donated (ibid.) and global health commitments made through âThe London Declarationâ in 2012 and Sustainable Development Goals (SDGs) in 2015, with national NTD master plans coordinated by the WHO. As of 2019, 67 countries implemented preventive chemotherapy (PC), the large-scale delivery of medicines at regular intervals to entire population groups (WHO, 2020), for one out of five diseases, with over one billion individuals receiving treatment for at least one disease, and there have been some strong achievements in elimination (ibid.). For example, Ecuador eliminated onchocerciasis in 2014 (WHO, 2015b), and Vietnam eliminated lymphatic filariasis in 2018 (Dung et al., 2020). These are significant successes in the space of approximately 20 years, seeing as the term âNTDsâ was only coined in the early 2000s. While much more is still to be done, it is remarkable progress. Considering these diseases have been labelled neglected, especially in terms of global public health awareness and commitments. What then were the events and milestones that led to such an outcome?