Neglected Diseases

Neglected Diseases PLOS Medicine's Neglected Diseases section began with the launch of the journal in October 2004. Up until February 2008, the section focused on tropical infectious diseases, such as Buruli ulcer, trachoma, and hookworm. A list of the 21 articles published from October 2004 to February 2008 can be found in the Supporting Information section of our February 2008 Editorial. With the launch of PLOS Neglected Tropical Diseases in October 2007, the focus of the Neglected Diseases section of PLOS Medicine shifted from tropical diseases to other health problems that could be considered neglected and that have a significant global burden (such as reproductive and maternal health problems, mental illness in low- and middle-income countries, road traffic injuries, and health problems related to migration and conflict.). Read the February 2008 Editorial for information about the section.

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Incorporating a Rapid-Impact Package for Neglected Tropical Diseases with Programs for HIV/AIDS, Tuberculosis, and Malaria

  • Peter J Hotez mail,

    To whom correspondence should be addressed. E-mail:

  • David H Molyneux,
  • Alan Fenwick,
  • Eric Ottesen,
  • Sonia Ehrlich Sachs,
  • Jeffrey D Sachs
  • Published: January 31, 2006
  • DOI: 10.1371/journal.pmed.0030102

Reader Comments (5)

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Response from World Health Organization

Posted by plosmedicine on 30 Mar 2009 at 23:53 GMT

Author: Dr Lorenzo Savioli
Position: Director, Department of Control of Neglected Tropical Diseases
Institution: World Health Organization, Geneva, Switzerland
Additional Authors: Dr Dirk Engels, Dr Denis Daumerie, Dr Jean Jannin, Dr Jorge Alvar, Dr Kingsley Asiedu, Dr Marc Gastellu-Etchegorry, Dr Pere Simarro, Dr Silvio P. Mariotti
Submitted Date: May 02, 2006
Published Date: May 3, 2006
This comment was originally posted as a “Reader Response” on the publication date indicated above. All Reader Responses are now available as comments.


We have read the article by Hotez et al. [1] and the letter by Torreele et al. [2] We would like to take this opportunity to give the point of view of the World Health Organization regarding the control of tropical diseases.

Approximately 1 billion people - one sixth of the world's population, or 1 person in 6 - suffer from one or more neglected tropical diseases (NTDs), such as Buruli ulcer, cholera, cysticercosis, dengue and DHF, dracunculiasis (guinea-worm disease), foodborne trematode infections, hydatidosis, leishmaniasis, lymphatic filariasis, onchocerciasis, schistosomiasis, soil-transmitted helminthiasis, trachoma, Chagas disease and human African trypanosomiasis. Several of these diseases are vector-borne. Some diseases affect individuals throughout their lives, causing a high degree of morbidity and physical disability and, in certain cases, gross disfigurement. Others are acute infections, with transient, severe and sometimes fatal outcomes. Patients can face social stigmatization and abuse, which only adds to the already heavy disease burden. The common denominator of all the NTDs is that these diseases are invariably the diseases of the poorest in low income countries.

For the majority of these diseases inexpensive or donated drugs are available for their prevention and control or part of strategies for control and elimination. These, when used on a large scale, are able to wipe out the burden caused by these ancient scourges of humanity. For leprosy, treatment with effective antibiotics, now kindly donated by Novatis, is leading to the elimination of this ancient disabling disease. In the case of blinding trachoma, the use of the recommended SAFE strategy including an effective antibiotic, donated by Pfizer through and ad hoc initiative (ITI), is enhancing the progress towards final elimination. Large-scale, regular treatment plays a central role in the control of many NTDs such as filariasis, onchocerciasis, schistosomiasis and soil-transmitted nematode infections. For example, regular chemotherapy against intestinal worms reduces mortality and morbidity in preschool children, improves the nutritional status and academic performance of schoolchildren, and improves the health and well-being of pregnant women and their infants.

There is a second group of NTDs for which the only clinical option currently available is systematic case-finding and management at an early stage. These diseases include Buruli ulcer, Chagas disease, cholera and other diarrhoeal diseases, human African trypanosomiasis, and leishmaniasis. Simple diagnostic tools and safe and effective treatment regimens need to be developed urgently for these diseases. However, even for these infections, systematic and widespread use of the present, "imperfect" tools at an early stage of disease can dramatically reduce mortality, morbidity and disability. For others, vector control tools are available and present the main method for successful transmission control, as in the case of Chagas disease.

There are examples of great successes in the fight against NTDs in both these groups and offer optimism for the future. Since 1985, 14.5 million patients have been cured of leprosy through multidrug therapy; today, less than a million people are newly affected by the disease. Before the start of the Guinea-worm Eradication Programme in the early 1980s, an estimated 3.5 million people were infected with the disease in 20 endemic countries. In 2005, only about 10 000 cases were reported in 9 endemic countries, and the programme is moving towards eradication by 2009.

The control of onchocerciasis has freed more than 25 million hectares of previously onchocerciasis-infested and available for resettlement and agricultural cultivation, thereby considerably improving rural development prospects in Africa and Latin America. During the last years, thanks to the PPP with sanofi-aventis, human African trypanosomiasis control activities have increased, raising the total number of people screened through active case-finding and subsequently increasing the access to diagnosis and treatment of affected populations. These constant efforts have led to a substantial and regular decline in the number of new cases. The number of people infected which were estimated at 300 000 cases in 1995 have been reduced to 50 000 - 70 000 in 2005. [3]

In other words, the area of neglected tropical diseases is not only an area lacking drugs and tools that can effectively treat affected individuals and communities but an area of action. As an example praziquantel, a very effective, safe and relatively cheap single dose drug (approximately 0.20 Euro per dose) to treat schistosomiasis, affecting only in Africa at least 160 million people, is not accessible to those in need due to lack of financial resources to purchase and deliver it. We also have a series of other effective antischistosomal drugs like oxamniquine and metrifonate that could again be made available in case resistance to praziquantel were to develop. Triclabendazole, the only effective drug against fascioliasis, has been on the market for veterinary use for over 20 years and is still not widely available for human use. Other drugs to tackle onchocerciasis and lymphatic filariasis are generously given free by the producers, Merck & Co., Inc. and GSK, but more funds are required to deliver them to the millions in need.

These and many other highly effective drugs developed in the late 70s are now out of patent but still not available to poor communities. We are well aware that "market mechanisms" will never solve the problem of access to effective drugs in the poorest communities of the low income countries. Therefore action with drug donations and funds for drug delivery is needed to tackle the problem that is intimately linked to underdevelopment and marginalization.

Global health development policies must also be more balanced in allocating resources to research and control. For instance the recent resolution of the European Parliament [4] is indeed a sign of great progress. However this document tackles disproportionately the lack of tools and the need for research in drug development. We believe that above all priority should be given to generating resources to deliver the drugs already available to those in need while monitoring their use and efficacy.

WHO is expanding activities in this area. WHO has very recently developed guidelines towards effective integrated implementation of large scale preventive chemotherapy strategies in consultation with Member States, academic organizations and other partners. We believe these guidelines will be essential for Member States and interested non-governmental organizations to tackle the problem of neglected tropical diseases in their countries on a large scale.

The priority today is immediate action to expand delivery of effective tools and to strengthen the capacity of health and innovative delivery systems in the poorest sections of endemic countries. To this end it is extremely important that all these neglected diseases be place on the political agenda of the World Health Assembly and a special effort needs to be paid to incorporating the missing ones, like leishmaniasis. We agree that in the medium and long-term, this must be backed up by research and development of new drugs, vaccines, like those presently developed against hookworms, diagnostics and other tools. We believe that focusing mainly on R&D at this stage is overshadowing the importance of reducing mortality, morbidity and disability now with the existing technology.

Dr Lorenzo Savioli
Department of Control of Neglected Tropical Diseases
WHO, Geneva

Dr Dirk Engels
Preventive Chemotherapy and Transmission Control
Department of Control of Neglected Tropical Diseases
WHO, Geneva

Dr Denis Daumerie,
Project Manager
Strategy Development and Implementation Coordination Project
Department of Control of Neglected Tropical Diseases
WHO, Geneva

Dr Jean Jannin
Innovative and Intensified Disease Management
Department of Control of Neglected Tropical Diseases
WHO, Geneva

Dr Jorge Alvar
Medical Officer Leishmaniasis Control
Innovative and Intensified Disease Management
Department of Control of Neglected Tropical Diseases
WHO, Geneva

Dr Kingsley Asiedu
Medical Officer
Global Buruli Ulcer Initiative
Department of Control of Neglected Tropical Diseases
WHO, Geneva

Dr Marc Gastellu-Etchegorry,
Medical Officer
Innovative and Intensified Disease Management
Department of Control of Neglected Tropical Diseases
WHO, Geneva

Dr Pere Simarro
Medical Officer
Human African Trypanosomiasis Control
Innovative and Intensified Disease Management
Department of Control of Neglected Tropical Diseases
WHO, Geneva

Dr Silvio P. Mariotti
Medical Officer
Prevention of Blindness
Chronic Disease Prevention and Management
WHO, Geneva

1. Hotez, P.J. et al. (2006) Incorporating a rapid impact package for neglected tropical diseases with programmes for HIV/AIDS, tuberculosis and malaria. PLoS Med 3 (5): e102.
2. Torreele E., et al. (2006) to fully tackle Gang of 4, needs driven R&D is essential.
3. Weekly epidemiological record No. 8, 2006, 81, 69-80.
4. European Parliament resolution on Major and Neglected Diseases in Developing Countries (2005/2047(INI))

Competing interests declared: I have now had time to read the conflict of interest guidelines and can confidently affirm that to the best of my knowledge myself and all co-authors do not have any conflict of interest as International Civil servants of the UN system.