Neglected Tropical Diseases
Liverpool School of Tropical Medicine, UK
This series provides a unique, up to date, and authoritative overview of Neglected Tropical Diseases in both the individual diseases and the cross cutting issues, such as Water and Sanitation and community roles, for the teaching and benefit of researchers, students, and staff in pharmaceutical companies, research institutions, and development... read moreorganisations.
The concept of neglected tropical diseases (NTDs) emerged in 2004/2005 and has been recognised as a valid way to categorise diseases that affect the poorest individuals in poor populations. Substantial progress in their control and elimination has been achieved and a policy momentum has been generated through continued bilateral, philanthropic, and nongovernmental development organisation (NGDO) support, and through the donations of drugs from pharmaceutical companies. Some 70 countries are implementing programmes with varying levels of dependency on donor support, through various approaches. WHO has defined a Roadmap to reach 2020 targets, which was endorsed by member states in a World Health Assembly Resolution in 2013. NTDs have been included within the Sustainable Development Goal (SDG) targets and are a crucial component of universal health coverage, conceptualised as “leaving no one behind”. NTDs are addressed through five strategies: preventive chemotherapy, intensified disease management, vector control, veterinary public health measures for zoonotic neglected diseases, and improved water and sanitation, as defined in a World Health Assembly Resolution of 2013. The research agenda has defined the need for affordable products (diagnostics, drugs and insecticides). However, challenges such as insecurity and weak health systems continue to prevail in the poorest countries, inhibiting progress in scaling up and achieving Roadmap goals.
The drive for the control or elimination of NTDs has had many successes, but to address challenges in reaching ‘end game’ targets of elimination and eradication, there is a need for adaptive approaches as well as multi-disciplinary collaboration and intersectoral action. This requires greater engagement of endemic countries through the recognition of the burden of NTDs as drivers of poverty, as impediments to socio economic development, and the cost-effectiveness and cost benefit of interventions. The advent of the NTD movement has resulted in massive up-scaling of the delivery of essential and quality medicines to around a billion people annually. Recipients are often the poorest of the poor, thus forging the global aspiration that universal health coverage is possible, equitable and affordable, as reflected within the 2030 Sustainable Development Goals (SDGs). However, significant challenges remain, including profound socio-political upheavals (conflict, migration), dynamic epidemiological settings (climate change, environmental degradation, urbanization), and a need for innovative approaches to programme delivery as well as scientific and technological advances. To reach ‘endgame’ targets, the NTD community will need to continue to adapt to these global events and changing policy environments to support the development of responsive and resilient programmes that can sustain progress toward NTD targets in the everchanging world.
We have suggested that NTDs represent “a global pandemic” and question why only 0.6 % of Official Development Assistance for health is devoted to a group of infections that kill an estimated 350,000 people annually and inflict poverty on a billion plus. The NTD programmes treat some one BILLION people annually. The challenges of elimination and eradication and achievement of WHO Road Map Targets can be categorised as: resources (human and financial), effectiveness of available tools, continuous innovation, limited national capacity, improving the uptake of vector control, accessing remote populations, security and conflict, high costs of the “last mile” in elimination and eradication programmes; elimination and eradication programmes have a 20 year plus timeframe requiring a longer term perspective often beyond donor horizon.
The Impact of socio-political, geographic, ecological and climate factors on NTD epidemiology, and the difficulty of treatment and control in rapidly expanding and complex urban settings, exemplify other major challenges. Can the health community respond to rapidity of change in epidemiology? Can new products be introduced and resourced in sufficient time to make an impact as WHO impose rigorous requirements before recommending introducing new policies to treat or control infectious organisms and vectors? Many organisms have the capacity to respond to selective pressures faster than any policy response. This makes policy guidance and implementation of that policy behind the curve of what is critically needed should problems such as resistance occur.
It is important that endemic countries are aware of the problems NTDs pose to their populations and the economic and social benefits that accrue from implementing recommended WHO strategies. The value and leverage provided by drug donations of NTD drugs and the low delivery costs, often at less than 0.50 US$/annum, provide a huge opportunity to provide essential drugs valued at 2-3 BILLION US$/year, given that delivery costs represent a small percentage of per capita national health expenditure even for the poorer countries which have the highest burden of NTDs.
One of the challenges within countries is working with other compatible programmes, e.g. malaria and vector control in Africa for filariasis; HIV/AIDS and schistosomiasis. There are significant opportunities for programme synergies, e.g. with polio for surveillance and laboratory diagnosis; bed nets for malaria and lymphatic filariasis; impact of improved WASH on NTDs (trachoma and Guinea worm); hence there is a need to greater appreciate the benefits of linking country programmes. For example, how can we engage the WASH and Education sectors for STH and schistosomiasis to play a key role in the provision of services and drug distribution via schools; similarly, for rabies control via dog vaccination - who pays, the health or the veterinary sector?