A Paradigm Shift

In 2003, under the leadership of Dr. J. W. Lee, just appointed Director General, the World Health Organization (WHO) started a process of paradigm shift in the control and elimination of neglected tropical diseases (NTDs) (Box A19-1). The shift consisted of the adoption of a new vision that abandoned a purely academic approach to adopt one more responsive to the needs of affected individuals and communities. As a consequence, it entailed a strategic rethinking and a move away from a “theoretical,” structural classification based on disease biology toward a “practical” one based on the available tools employed to control such diseases.

BOX A19-1

NTDs and Their Common Features. The list of NTDs is vast and virtually open ended. For the time being, WHO's work is confined to a list of 17 selected helminth, protozoal, and bacterial diseases. There are 149 countries and territories where NTDs are (more...)

For a group of afflictions, mainly helminth infections, this shift generated a radical change in the public health control approach, which no longer consisted of the disease-specific implementation of isolated interventions but was now focused on a broader, person-centered concept involving large-scale provision of treatment in an integrated fashion. This paradigm shift was undertaken to ensure a more efficient use of the limited resources available and with the objective to help marginalized rural and urban population groups to pull themselves out of the vicious cycle of poverty and illness.

This paradigm shift toward integrated control of NTDs was a result of a long intellectual process that covered three major areas:

1. the generation and acquisition of the necessary scientific knowledge;
2. the promotion and dissemination of the intervention strategies to decision makers in endemic countries; and
3. the building of the consensus among the potential partners as a way to secure the financial and in-kind resources.

Table A19-1 illustrates the steps that were taken for the development of the scientific knowledge and evidence necessary to support the integrated control of helminth infections. This process covered a period of more than three decades, from the initial idea of a single tablet to treat schistosomiasis and soil-transmitted helminths (STHs) to the complete development of the necessary armamentarium of active drugs and strategies for distribution.

TABLE A19-1

Main Steps for the Development of Scientific Knowledge for NTD Control.

Table A19-2 presents the steps taken for the promotion of implementation of NTD control activities: this process took at least one decade from the leading article of Savioli et al. (1992) in the Transactions of the Royal Society of Tropical Medicine and Hygiene to the World Health Assembly resolution of 2001 and another 10 years to the recent launch of the first WHO report on neglected tropical diseases (2010d).

TABLE A19-2

Steps for the Promotion of Implementation of NTD Control.

The donations and financial supports that made possible the scale-up of NTD control are presented in Table A19-3; the process starts with the first donation of ivermectin for the control of onchocerciasis in 1987, to the multiple and expanding donation from GlaxoSmithKline (GSK), Johnson & Johnson (J&J), and Eisai in 2010.

TABLE A19-3

Steps for the Building of Consensus Among Partners and Donors.

New Strategic Approaches

The main outcome of the NTD paradigm shift in the field of helminth infections was the definition and launch of the “new drug strategy” called preventive chemotherapy. The mainstay of the strategy is a population-wide, drug-based approach that supersedes the old disease-specific “compartments” that determined a scenario in which treatment of specific forms of helminthiasis was provided separately; preventive chemotherapy is rather centered on the best, coordinated use of the available medicines for a synergic action against a number of afflictions.

In 2006, Preventive Chemotherapy in Human Helminthiasis (WHO, 2006) recommended the integrated implementation of disease interventions against the four main helminth infections (schistosomiasis, soil-transmitted helminthiasis, lymphatic filariasis, and onchocerciasis) based on the coordinated use of a set of anthelminthic drugs, thereby expanding to two new diseases the integration efforts made previously for schistosomiasis and soil-transmitted helminthiasis. This strategy is made possible by the availability of powerful, safe, and easy-to-administer medicines that bring immediate, dramatic, and continued relief. Treatment can be extended to all at-risk populations through innovative delivery mechanisms put in place by nontechnical personnel, such as teachers and community-based volunteers. Regular treatment improves maternal health, reduces neonatal mortality, promotes childhood growth and development, increases school attendance and performance, and avoids chronic irreversible disease at a later stage in life. The major challenge for the implementation of preventive chemotherapy is to expand its coverage in order to provide all at-risk populations with regular treatment. In spite of logistic challenges, preventive chemotherapy interventions are currently implemented on a worldwide scale and more than half a billion individuals are treated every year (WHO, 2010a, 2010b, 2010c).

The increasing success of this approach is boosted by a number of factors:

• the clear demonstration of the association of such infections with poverty and economic burden (Hotez et al., 2009);
• the geographical overlap existing among the four diseases targeted (Clements et al., 2010);
• the contribution of preventive chemotherapy not only to morbidity reduction but also to sustained decrease of transmission (Sinuon et al., 2007);
• its added benefits on a number of affections not specifically targeted by the intervention (such as scabies and lice) (Mumcuoglu and Gilead, 2008);
• its flexibility, which allows the expansion of its target to virtually any helminth infection, as shown by the case of fascioliasis and other food-borne trematode infections (Keiser et al., 2010); and
• the fact that drug delivery mechanisms in place for helminth control can be used as a platform to target other communicable diseases such as trachoma (Hu et al., 2010) paves the way for a further expansion of this public health approach which now shares, from an organizational and logistic perspective, many common features with immunization.

In the field of protozoan and bacterial diseases such as African sleeping sickness, leishmaniasis, Chagas disease, Buruli ulcer, and yaws, the main outcome of the NTD paradigm shift has been a new focus on improved and timely access to specialized care through a better case detection and an effective decentralization of clinical management, in an effort to preventing mortality and reducing morbidity and transmission (please refer to Appendix pages 310–323). Even if these diseases are tackled effectively, it requires the specific expertise of skilled personnel, and if dramatic and sustainable steps forward must await the development of better, safer, more affordable, and simpler-to-use diagnostics and drugs, it is clear that this group of infections could also immediately benefit from a more coordinated strategic approach if the focus of the intervention was shifted to a wider access to treatment for those in need, through an innovative and intensified case management aimed at optimizing the use of existing tools (WHO, 2010d).

Vector control was also rethought in light of the new, integrated strategic framework as a key crosscutting activity to be implemented in conjunction and coordination with both preventive chemotherapy and intensified case management. As such, integrated vector management was launched as an effective combination of different interventions as well as an intersectoral and interprogrammatic collaboration within the health sector and between this and other sectors, such as agriculture and the environment. Its aim is to improve the efficacy, cost-effectiveness, ecological soundness, and sustainability of disease control interventions implemented against those NTDs that are vector borne and that are in fact the majority (WHO, 2010d).

Rebranding

Following the development of the new strategic approaches, it was time for a change in name: in 2005, at the historical meeting in Berlin,⁴² WHO formally rebranded this area of work, previously vaguely defined as “other communicable diseases” or “other tropical diseases,” meaning other than malaria, tuberculosis, and HIV/AIDS, as neglected tropical diseases. The Berlin meeting also defined the NTDs as a set of infectious diseases—most of which are preventable and/or treatable—that remained among the primary causes of death and ill health among the poorest sectors of the population worldwide. In such a manner the international community recognized that many other chronically endemic tropical diseases, beyond the aforementioned “big three,” were still much neglected in the global public health agenda and had to be moved out of the shadows. WHO convened this meeting with partners and experts to secure strategic and technical guidance and take this agenda forward.

On April 17 and 18, 2007, WHO convened the first Global Partners' Meeting on NTDs. Some 200 participants attended the meeting, including representatives of WHO Member States, United Nations agencies, the World Bank, philanthropic foundations, universities, pharmaceutical companies, international nongovernmental organizations, and other institutions dedicated to contributing their time, efforts, and resources to tackle neglected tropical diseases. Guests of honor included His Excellency Mr. Blaise Compaoré, President of Burkina Faso, and Mr. Samuel Eto'o, the Cameroonian footballer. This meeting declared to the world that the burden represented by NTDs is substantial and as such it deserves attention and high priority on the global public health agenda; that prevention, control, elimination, and eradication of these diseases is possible, but greater determination is required to achieve these goals through delivery of appropriate health care to the millions of poor people in need. “This event marks a turning point in the long and notorious history of some of humanity's oldest diseases,” said WHO Director-General Dr. Margaret Chan in her opening address. “The burden imposed by these diseases, measured in terms of human misery alone, is unacceptable. We are committed to take action.”

Lessons Learned and Successes Achieved

Even if only a few years have elapsed since the start of the NTD paradigm shift, it is already possible to appreciate some of its positive effects: overall, it has enabled Member States and partners to find innovative solutions enabling weak health systems to target the people most in need: the poorest sectors of the population with limited or non-existent financial means. Grouping several diseases together under the NTD framework has offered the opportunity to start recalculating the collective burden associated with this set of very diverse afflictions as well as their cumulative public health relevance and, consequently, to raise attention and mobilize resources for a world-scale implementation of disease control and elimination activities.

Despite the fact that many low-cost and effective interventions are available to tackle most of these diseases, the majority of affected populations do not yet have access to adequate treatment and care (WHO, 2010d). Nevertheless, where disease control interventions have been implemented, “hidden” but relevant successes have shown that these diseases can be effectively managed, and in certain instances elimination and eradication are undeniable possible outcomes (WHO, 2010d). Achieved successes have gradually come to light, offering an opportunity for expansion and generating interest by an increasing number of Member States, bilateral and multilateral donors, and new partners engaged in poverty alleviation.

The heavy burden imposed by NTDs on poor people is gaining wider recognition and prominence by countries and institutions with the capacity to release resources for prevention and control (Hotez and Kamath, 2009). Effective advocacy has successfully exploited the notion of neglect and stimulated health policy makers to work to overcome the burden associated with NTDs in harmony with the ideals and aims of the United Nations Millennium Development Goals (Boutayeb, 2007). Available tools for treatment intervention in communities are now reaching millions in need, offering evidence that, where interventions are implemented, results can be achieved with comparably limited investments.

Current Opportunities and Challenges

Experience shows that transmission of NTDs can decrease to the point of interruption, especially when treatment is complemented by improvements in safe water supply, housing, hygiene and sanitation, vector control, and veterinary public health measures (Huppatz et al., 2009; Sinuon et al., 2007). Control of NTDs is a highly cost-effective exercise with immediate benefits that are powerfully visible. These benefits, in turn, stimulate public demand for treatment, thus paving the way for community engagement.

The NTDs have the unique advantage of major donations from the pharmaceutical industry. Hundreds of millions of treatments are donated yearly to address the fight against both the “tool-ready” and the “tool-deficient” disease groups. This healthy relation between the public and private sectors answers the need for access to free treatment for the poorest in endemic countries.

Much has been accomplished, but more resources are needed, on the one hand, to expand treatment coverage of both preventive chemotherapy and case management, and on the other hand, to support the research and development required to develop, test, and produce new medicines and diagnostics. Such investments are crucial to progressively expand what is already working and to sustain the advancement and the progress in the control of the tool-deficient group of infections. The ultimate goal is to ensure that all populations in need have timely access to effective, simple, and safe single doses medications against any NTDs.

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Footnotes

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Report of the WHO Strategic and Technical Meeting on Intensified Control of Tropical Diseases, available at http://whqlibdoc​.who​.int/hq/2006/WHO_CDS_NTD_2006.1_eng.pdf.