David H. Molyneux

Incorporating a rapid-impact package for neglected tropical diseases with programs for HIV/AIDS, tuberculosis, and malaria

Hotez et al. argue that achieving success in the global fight against HIV/AIDS, tuberculosis, and malaria may well require a concurrent attack on the neglected tropical diseases.

Rescuing the bottom billion through control of neglected tropical diseases

Here we outline low-cost opportunities to control the neglected tropical diseases through preventive chemotherapy, and propose fi nancial innovations to provide poor individuals with essential drugs.13 parasitic (helminthic and protozoan) and bacterial tropical infections, and dengue are the highest-burden neglected tropical diseases; another 20 include fungal, viral, and ectoparasitic infections (panel 2).

Unhealthy landscapes: policy recommendations on land use change and infectious disease emergence

Anthropogenic land use changes drive a range of infectious disease outbreaks and emergence events and modify the transmission of endemic infections. These drivers include agricultural encroachment, deforestation, road construction, dam building, irrigation, wetland modification, mining, the concentration or expansion of urban environments, coastal zone degradation, and other activities. These changes in turn cause a cascade of factors that exacerbate infectious disease emergence, such as forest fragmentation, disease introduction, pollution, poverty, and human migration. The Working Group on Land Use Change and Disease Emergence grew out of a special colloquium that convened international experts in infectious diseases, ecology, and environmental health to assess the current state of knowledge and to develop recommendations for addressing these environmental health challenges. The group established a systems model approach and priority lists of infectious diseases affected by ecologic degradation. Policy-relevant levels of the model include specific health risk factors, landscape or habitat change, and institutional (economic and behavioral) levels. The group recommended creating Centers of Excellence in Ecology and Health Research and Training, based at regional universities and/or research institutes with close links to the surrounding communities. The centers’ objectives would be 3-fold: a) to provide information to local communities about the links between environmental change and public health; b) to facilitate fully interdisciplinary research from a variety of natural, social, and health sciences and train professionals who can conduct interdisciplinary research; and c) to engage in science-based communication and assessment for policy making toward sustainable health and ecosystems.

Rapid-impact interventions: how a policy of integrated control for Africa's neglected tropical diseases could benefit the poor.

Controlling seven tropical infections in Africa would cost just 40 cents per person per year, and would permanently benefit hundreds of millions of people.

Deforestation: effects on vector-borne disease

This review addresses changes in the ecology of vectors and epidemiology of vector-borne diseases which result from deforestation. Selected examples are considered from viral and parasitic infections (arboviruses, malaria, the leishmaniases, filariases, Chagas Disease and schistosomiasis) where disease patterns have been directly or indirectly influenced by loss of natural tropical forests. A wide range of activities have resulted in deforestation. These include colonisation and settlement, transmigrant programmes, logging, agricultural activities to provide for cash crops, mining, hydropower development and fuelwood collection. Each activity influences the prevalence, incidence and distribution of vector-borne disease. Three main regions are considered--South America, West & Central Africa and South-East Asia. In each, documented changes in vector ecology and behaviour and disease pattern have occurred. Such changes result from human activity at the forest interface and within the forest. They include both deforestation and reafforestation programmes. Deforestation, or activities associated with it, have produced new habitats for Anopheles darlingi mosquitoes and have caused malaria epidemics in South America. The different species complexes in South-East Asia (A. dirus, A. minimus, A. balabacensis) have been affected in different ways by forest clearance with different impacts on malaria incidence. The ability of zoophilic vectors to adapt to human blood as an alternative source of food and to become associated with human dwellings (peridomestic behaviour) have influenced the distribution of the leishmaniases in South America. Certain species of sandflies (Lutzomyia intermedia, Lu. longipalpis, Lu. whitmani), which were originally zoophilic and sylvatic, have adapted to feeding on humans in peridomestic and even periurban situations. The changes in behaviour of reservoir hosts and the ability of pathogens to adapt to new reservoir hosts in the newly-created habitats also influence the patterns of disease. In anthroponotic infections, such as Plasmodium, Onchocerca and Wuchereria, changes in disease patterns and vector ecology may be more difficult to detect. Detailed knowledge of vector species and species complexes is needed in relation to changing climate associated with deforestation. The distributions of the Anopheles gambiae and Simulium damnosum species complexes in West Africa are examples. There have been detailed longitudinal studies of Anopheles gambiae populations in different ecological zones of West Africa. Studies on Simulium damnosum cytoforms (using chromosome identification methods) in the Onchocerciasis Control Programme were necessary to detect changes in distribution of species in relation to changed habitats. These examples underline the need for studies on the taxonomy of medically-important insects in parallel with long-term observations on changing habitats.(ABSTRACT TRUNCATED AT 400 WORDS)

Lymphatic filariasis elimination: progress in global programme development.

The Global Programme to Eliminate Lymphatic Filariasis (GPELF) is an innovative, public-private partnership for health improvement. The progress made since the programme was initiated, in 1998, is here reviewed. The programme is largely based on the regular mass administration of albendazole with either ivermectin (Mectizan(R)) or diethylcarbamazine. Both albendazole and ivermectin have been donated by their manufacturers, for as long as necessary. The first national campaigns based on these drugs commenced in late 1999. Since then, rapid progress has been made in confirming the safety of the drug combinations, establishing a regional approach, and recognizing that experiences, epidemiological settings, health systems, the best drug combinations and disease burdens all vary with the country involved. There is a continuing trend towards decentralization, and this should lead to greater regional and national ownership and more inter-country activities. The progress made in mapping the geographical distribution of lymphatic filariasis (LF), by designated implementation units and, ultimately, by country, is also summarized. Country-specific methods of social mobilization and drug distribution, that are compatible with health planning at central and district level, need to be developed. However, the assessment of coverage by mass drug administration (MDA) needs to be strengthened, to allow reliable national monitoring and inter-country or inter-region comparisons. Valuable contributions made by non-governmental development organizations (NGDO) and civil society organizations (CSO) are acknowledged, such organizations (and particularly local NGDO) should be encouraged to help more in implementing the various activities at district level. The GPELF has developed during an era of considerable change in international health policy. The programme can contribute to the relief of poverty, as LF is closely associated with low-income communities in the least developed countries and MDA is a pro-poor intervention. There are clear opportunities for linking the activities of the GPELF (which uses cheap or free drugs that bring considerable incidental health benefits, in addition to arresting the transmission of the parasites causing LF) with other health interventions. New evidence indicates that annual treatments with antifilarial drugs greatly reduce the clinical abnormalities of the disease. The programme has expanded rapidly, with the annual number of people treated rising from 2.9 million (in 12 countries) in the year 2000 to 25.89 million (in 22 countries) in 2001 and an estimated 80 million (in 34 countries) in 2002. At the recent meeting of the Global Alliance, held in New Delhi in May 2002, a significant but realistic challenge - of scaling-up the programme to cover up to 350 million of those at risk, by the end of 2005 - was set. The rate of growth necessary to meet this target presents considerable strategic and managerial challenges to all of the partners involved in the programme, from the development of synergies with other, large-scale, public-health interventions to the logistics of drug manufacture, shipping and local transportation and resolving the problems of social mobilization, reporting, evaluation and monitoring on such a scale. Such challenges are, however, easily outweighed by the potential benefits of success. If the international health community cannot provide the necessary support to complement the investments being made by the endemic countries (as they scale-up their LF-elimination campaigns and ensure yearly access to two free and efficacious drugs that bring major benefits to those treated), significant progress in the control of other infectious diseases becomes a very distant goal.

Socioeconomic aspects of neglected tropical diseases

Although many examples of highly cost-effective interventions to control neglected tropical diseases exist, our understanding of the full economic effect that these diseases have on individuals, households, and nations needs to be improved to target interventions more effectively and equitably. We review data for the effect of neglected tropical diseases on a populations health and economy. We also present evidence on the costs, cost-effectiveness, and financing of strategies to monitor, control, or reduce morbidity and mortality associated with these diseases. We explore the potential for economies of scale and scope in terms of the costs and benefits of successfully delivering large-scale and integrated interventions. The low cost of neglected tropical disease control is driven by four factors: the commitment of pharmaceutical companies to provide free drugs; the scale of programmes; the opportunities for synergising delivery modes; and the often non-remunerated volunteer contribution of communities and teachers in drug distribution. Finally, we make suggestions for future economic research.

The neglected tropical diseases: the ancient afflictions of stigma and poverty and the prospects for their control and elimination.

The World Health Organizations and other international health agencies identify a select group of 13 tropical infections as the neglected tropical diseases (NTDs). These diseases, which include leprosy, kala-azar, river blindness, guinea worm, schistosomiasis, hookworm and lymphatic fi lariasis, strike the world’s poorest people living in remote and rural areas of low-income countries in Sub-Saharan Africa, Asia and the Americas. They infl ict suffering by causing life-long disabilities, disfi gurement, reduced economic productivity, and social stigma (WHO, 2003). Unlike better-known global health threats such as HIV-AIDS, malaria, and tuberculosis, the NTDs do not receive enough international attention. Instead, they are neglected diseases among forgotten people found only in the setting of geographic isolation and intense poverty (Molyneux, 2004). Impoverished and marginalized populations with the NTDs represent the lowest priority markets for U.S. and European pharmaceutical manufacturers. The NTDs do not occur in the industrialized world or even among the substantial wealthy and middle-classes in developing countries. They are not a signifi cant health risk for foreign travelers or the military. This is in contrast to the more substantial commercial markets for HIV-AIDS, malaria and tuberculosis (“the big three”). The recent creation of massive funding schemes for the big three, such as The Global Fund to Fight AIDS, Tuberculosis, and Malaria, and the U.S. President’s Emergency Plan for AIDS Relief provides additional fi nancial incentives, as well as a certain amount of panache and luster. In contrast, the commercial market for NTD drug

Neglected diseases but unrecognised successes— challenges and opportunities for infectious disease control

The Millennium Development Goals and a plethora of initiatives have focused on the control of HIV/AIDS tuberculosis and malaria. However a large group of diseases has been confimed to the “other diseases” category by health policy makers and politicians. These so-called neglected diseases are the viral bacterial and parasitic infections of the tropics (often vector borne) together with acute respiratory infections and diarrhoeal diseases of children. Despite the availability of cost-effective stable and successful control or elimination interventions large numbers of the world’s poorest people remain afflicted or are at risk from this group of diseases. The focus of health policy makers on HIV/AIDS tuberculosis and malaria as well as emerging or reemerging diseases causes funding for neglected diseases to be overlooked with deleterious effects on the social and economic wellbeing of the poorest quintile of populations in the least developed and low-to-middle income countries. (excerpt)

Vector relationships in the Trypanosomatidae.

Publisher Summary This chapter discusses the interaction between trypanosomatid flagellates and their invertebrate hosts—the majority of those discussed are vectors. It also discusses the lower vertebrate trypanosomes and their vectors and mammalian trypanosomes and their vectors. Trypanosoma (Herpetosorna) rangeli (T. Rangeli) is one of the most interesting of mammalian trypanosomes. It is a parasite of man and various mammals in Central and South America and is transmitted by the bite of reduviids, usually Rhodnius prolixus. T. (H.) rangeli is pathogenic to its vector. The relationship between mammalian and reptilian Leishmania may prove to be of importance in understanding the epidemiology of the human disease. The chapter elaborates on the monoxenous trypanosomatid in insects. Under natural conditions, there are several situations in which an individual vector may be infected with more than one species of trypanosomatid. Thus, the effects of one parasite on another may be important in the context of competition for sites of establishment and available vector resources or because one species may be pathogenic to the vector, thus reducing the transmissibility of both parasites. Mixed infections between trypanosomes and monoxenous flagellates will occur in many situations, but few have been discussed in the chapter.