Neglected tropical diseases

The importance of neglected tropical diseases has been underestimated since many are asymptomatic and have long incubation periods. The connection between death and a neglected tropical disease that has been latent for a long period is often not realized. There are three other major reasons that these diseases have been overlooked: they mainly affect the poorest countries of the developing world; in recent years public health efforts have focused heavily on decreasing the prevalence of HIV/AIDS, tuberculosis, and malaria Stigma Neglected tropical diseases are often associated with social stigma, making their treatment more complex. Public health research has only recently begun to focus on stigma as a component of the issue. From the 1960s onward, approximately one citation a year related to social stigma. In 2006, there were 458. Currently, the pharmaceutical industry views research and development as highly risky. For this reason, resources are not often put into the field of NTDs, and new chemical products are often expensive. A review of public and private initiatives found that of the 1,393 new chemical products that were marketed between 1975 and 1999, only 16 were related to tropical diseases or tuberculosis. The same review found that there was a 13-fold greater chance of a newly marketed drug being for central nervous system disorders or cancer than for an NTD. Because of a lack of economic incentives for the pharmaceutical industry, successful NTD treatment programs have often relied on donations. For instance, the Mectizan Donation Program has donated over 1.8 billion tablets of ivermectin. While developed countries often rely on government-run and private partnerships to fund such projects, developing nations frequently have significantly lower per-person spending on these diseases. Neglected diseases in developed nations Since 2008, the concept of "neglected diseases of poverty" has been developed and explored. This group of diseases, which overlaps with neglected tropical diseases, also pose a threat to human health in developed nations. In the United States alone, there are at least 12 million people with neglected parasitic infections. However, in the developed world, diseases that are associated with poverty are often not addressed comprehensively. This may be due to a lack of economic incentives and public policy failings. A lack of awareness prevents effective policy generation and leaves healthcare services unequipped to address the issue. Additionally, little effort is put into creating and maintaining large data sets on neglected diseases in the United States and other developed nations. The first summit on the issue was held by the Adler Institute on Social Exclusion in the United States in 2009. In Europe, a similar trend is seen. Neglected tropical diseases are concentrated in eastern and southern Europe, where poverty levels are highest. The most prevalent diseases in this region are ascariasis, trichuriasis, zoonotic helminth infections, and visceral leishmaniasis. Migration paths to Europe, most notably to Spain, have brought diseases to Europe as well. As many as 6,000 cases of Chagas disease have been introduced in this way. In response to a growing awareness of the burden on these populations, the European Centre for Disease Prevention and Control has laid out ten public health guidelines. They cover a variety of topics, from health education and promotion to community partnerships and the development of a minority healthcare workforce. == List of diseases ==

There is some debate among the WHO, CDC, and infectious disease experts over which diseases are classified as neglected tropical diseases. Feasey, a researcher in neglected tropical diseases, notes 13 neglected tropical diseases: ascariasis, Buruli ulcer, Chagas disease, dracunculiasis, hookworm infection, human African trypanosomiasis, leishmaniasis, leprosy, lymphatic filariasis, onchocerciasis, schistosomiasis, trachoma, and trichuriasis. Fenwick recognizes 12 "core" neglected tropical diseases: the same as above, excluding hookworm. These diseases result from four classes of causative pathogens: (i) protozoa (Chagas disease, human African trypanosomiasis, and leishmaniasis); (ii) bacteria (Buruli ulcer, leprosy, trachoma, and yaws), (iii) helminths or metazoan worms (cysticercosis/taeniasis, dracunculiasis, echinococcosis, foodborne trematodiases, lymphatic filariasis, onchocerciasis, schistosomiasis, and soil-transmitted helminthiasis); and (iv) viruses (dengue, chikungunya, and rabies). The WHO recognizes the twenty diseases below as neglected tropical diseases. Buruli ulcer Buruli ulcer is caused by the bacterium Mycobacterium ulcerans. It is related to the bacteria that cause tuberculosis and leprosy. Mycobacterium ulcerans produces a toxin, mycolactone, that destroys tissue. Morbidity takes the form of deformity, disability, and skin lesions, which can be prevented through early treatment with antibiotics and surgery. and Latin America. Chagas disease with Chagas disease. It has manifested as an acute infection with swelling of one eye (chagoma).|255x255px Chagas disease is also known as American trypanosomiasis. There are approximately 15 million people infected with Chagas disease. Chagas disease does not kill victims rapidly, instead causing years of debilitating chronic symptoms. It is caused by the vector-borne protozoa Trypanosoma cruzi. Dengue fever is usually not fatal, but infection with one of four serotypes can increase later susceptibility to other serotypes, resulting in a potentially fatal disease called severe dengue. Chikungunya virus is a member of the genus Alphavirus and family Togaviridae. The disease mainly occurs in Africa and Asia. Dracunculiasis Dracunculiasis is also known as Guinea-worm disease. In 2019, 53 cases were reported across four countries, a substantial decrease from 3,500,000 cases in 1986. It is not fatal, but can cause months of inactivity. It is caused by drinking water contaminated by water fleas infected with guinea-worm larvae. It is caused by ingesting parasites in animal feces. There are two versions of the disease: cystic and alveolar. Both versions involve an asymptomatic incubation period of several years. In the cystic version, liver cysts cause abdominal pain, nausea, and vomiting, while cysts in the lungs cause chronic cough, chest pain, and shortness of breath. In alveolar echinococcosis, a primary cyst develops, usually in the liver, in addition to weight loss, abdominal pain, malaise, and signs of liver failure. Untreated alveolar echinococcosis is fatal. Cystic echinococcosis is found in the eastern portion of the Mediterranean region, northern Africa, southern and eastern Europe, the southern portion of South America, and Central Asia. Alveolar echinococcosis is found in western and northern China, Russia, Europe, and northern North America. The mortality risk is very low, but the disease causes disfigurement and disability if untreated. Human African trypanosomiasis African trypanosomiasis (African sleeping sickness) is a somewhat rare protozoal disease, with fewer than 10,000 cases currently. Human African trypanosomiasis is vector-borne and spreads through the bite of the tsetse fly. There are an estimated 12 million people infected. It is a vector-borne disease caused by the bite of sandflies. Leishmaniasis can be treated with expensive medications. Leprosy According to recent figures from the WHO, 208,619 new cases of leprosy were reported in 2018 from 127 countries. It is most prevalent in India (69% of cases), Brazil, Indonesia, Nigeria, the Democratic Republic of the Congo, Madagascar, and East Africa from Mozambique to Ethiopia, with the highest relative incidence in India, Brazil, and Nepal. There are one to two million individuals currently disabled or disfigured due to past or present leprosy. It is caused by bacteria and transmitted through droplets from the mouth and nose of infected individuals. Leprosy causes disfigurement and physical disabilities if untreated. It is curable if treated early. and 40 million with deformities. but has lifelong implications, such as lymphoedema of the limbs, genital disease, and painful recurrent attacks. Most people are asymptomatic but have lymphatic damage. Up to 40 percent of infected individuals have kidney damage. It is a vector-borne disease, caused by nematode worms that are transmitted by mosquitoes. and washing skin can slow or even reverse damage. It is diagnosed with a finger-prick blood test. was added to the World Health Organization's list of neglected tropical diseases in December 2023. Onchocerciasis '' emerging from a blackfly|189x189px Onchocerciasis is also known as river blindness. There are 20.9 million people infected, and prevalence is higher in rural areas. Over 99 percent of cases are in sub-Saharan Africa. It is a vector-borne disease, caused by blackflies infected with the filarial nematode Onchocerca volvulus. There is a higher prevalence in rural areas, and it disproportionately affects children. Rabies is fatal after symptoms develop. It is caused by a lyssavirus transmitted through wounds or bites from infected animals. The symptoms are usually haematuria, bladder obstruction, renal failure, bladder cancer, periportal fibrosis, bladder fibrosis, liver fibrosis, portal hypertension, cervical lesions, ascites, and esophageal varices. The four major worm species responsible for soil-transmitted helminthiasis are Ascaris (roundworms), Trichuris (whipworm), the hookworms Necator americanus and Ancylostoma duodenale, and Strongyloides stercoralis. There are 1.5 billion people currently infected. Both cysticercosis and taeniasis are found in Asia, Africa, and Latin America, particularly on farms in which pigs are exposed to human excrement. Cysticercosis occurs after ingestion of food, water, or soil contaminated by human fecal matter. It is usually contracted after eating undercooked contaminated pork or beef. Taeniasis has mild symptoms, including abdominal pain, nausea, diarrhea, or constipation, although cholangitis and appendicitis have been reported due to internal movement of motile proglottids, Drugs are used to treat both diseases. Trachoma There are 21.4 million people infected with trachoma, of whom 2.2 million are partially blind and 1.2 million are blind. It is found in Africa, Asia, Central and South America, the Middle East, and Australia. The mortality risk is very low, although multiple re-infections eventually lead to blindness. Scabies Snakebite envenoming Snakebite was added to the list in 2017, after years of criticism of the WHO by activists for not making it a priority. The greatest burden of snakebite morbidity is in India and Southeast Asia. Snakebite envenoming (SBE) affects as many as 2.7 million people every year, most of whom live in some of the world's most remote, poorly developed, and politically marginalised tropical communities. With annual mortality of 81,000 to 138,000 and 400,000 surviving victims suffering permanent physical and psychological disabilities, SBE is a disease in urgent need of attention, but snakebites often go unreported. A policy analysis however found that the placement of snakebite in the global health agenda of WHO is fragile due to reluctance acceptance of the disease in the neglected tropical disease community and the perceived colonial nature of the network driving the agenda. == Effects for patients ==

Social effects Social stigma Several NTDs, such as leprosy, cause severe deformities that result in social stigma. Stigma is considered to be the "hidden burden" of NTDs and is not accounted for in measures such as disability-adjusted life years (DALYs). Other NTDs that carry heavy social stigma include onchocerciasis, lymphatic filariasis, plague, Buruli ulcer, leishmaniasis, and Chagas disease. Lymphatic filariasis, for example, causes severe deformities that can result in denial of marriage and inability to work. More research needs to be directed to understanding psychological aspects of NTDs to understand their effects more fully and to direct strategies to manage them better in healthcare systems where mental health professionals are scarce. There is also added risk of hookworm infection during pregnancy and potential to transfer diseases such as Chagas during pregnancy. A study in Uganda found that women were able to obtain treatment more easily than men because they had fewer occupational responsibilities and were more trusting of treatments, but ignorance of the effects of medicines during pregnancy prevented adequate care. The paper concludes that gender should be considered when designing treatment programs in Uganda. Additionally, women often bear a heavier social stigma in relation to the pressure to marry. The low cost of treatment for NTDs can be attributed to the large scale of the programs, free provision of drugs by pharmaceutical companies, delivery modes of drugs, and unpaid volunteers who distribute the drugs. The economic burden of NTDs is undervalued and therefore the corresponding economic effect and cost-effectiveness of decreasing prevalence of NTDs is underestimated. Health effects Coinfection Coinfection is a major concern with NTDs, making them more damaging than their mortality rates might suggest. Because factors such as poverty, inadequate healthcare and inadequate sanitation practices contribute to all NTDs, they are often found in overlapping distributions. Helminth infections, as the most common infection of humans, are often found to be in multi-infection systems. For example, in Brazil, low socioeconomic status contributes to overcrowded housing. In these same areas, coinfection by Necator americanus and Schistosoma mansoni is common. The effect of each worm weakens the immune system, making infection from the other more likely and more severe. For this reason, coinfection carries a higher risk of mortality. NTDs may also play a role in infection with other diseases, such as malaria, HIV/AIDS, and tuberculosis. The ability of helminths to manipulate the immune system may create a physiological environment that could exacerbate the progression of HIV/AIDS. Some evidence from Senegal, Malawi, and Thailand has shown that helminth infections raise the risk of malarial infection. == Prevention, treatment and eradication ==

through education and distribution of anti-parasitic drugs Prevention and eradication are important because "of the appalling stigma, disfigurement, blindness and disabilities caused by NTDs." The declaration is a collaborative effort involving the WHO, the World Bank, the Bill & Melinda Gates Foundation, the world's 13 leading pharmaceutical companies, and government representatives from the US, UK, United Arab Emirates, Bangladesh, Brazil, Mozambique, and Tanzania. While there has been a noticeable uptick in biological research into NTDs, prevention may be supplemented by social and development outreach. Spiegel and coauthors advocated for "social offset", which reallocates some funding for biotechnological research to social programs. This attempts to alleviate some of the factors (such as poverty, poor sanitation, overcrowding and poor healthcare) that greatly exacerbate conditions brought on by NTDs. Projects such as these also strengthen the goal of sustained eliminations rather than quickly addressing symptoms. Policy initiatives There are many prevention and eradication campaigns funded by organizations such as the World Health Organization, US Agency for International Development, Bill & Melinda Gates Foundation, and UK Department for International Development. WHO Roadmap of 2012 In 2012, WHO published an NTD "roadmap", which contained milestones for 2015 and 2020, and specified targets for eradication, elimination and intensified control of the different NTDs. For example: • NTDs planned to be eradicated: dracunculiasis by the year 2015, endemic treponematoses (yaws) by 2020 • NTDs planned to be eliminated globally by 2020: blinding trachoma, leprosy, human African trypanosomiasis, and lymphatic filariasis • NTDs planned to be eliminated in certain regions: rabies (by 2015 in Latin America, by 2020 in Southeast Asia and the western Pacific), Chagas disease (transmission through blood transfusion by 2015, intra-domiciliary transmission by 2020 in the Americas), visceral leishmaniasis (by 2020 in the Indian subcontinent), onchocerciasis (by 2015 in Latin America), and schistosomiasis (by 2015 in the eastern Mediterranean region, the Caribbean, Indonesia, and the Mekong River basin, and by 2020 in the Americas and western Pacific) • NTDs planned to be eliminated in certain countries: human African trypanosomiasis (by 2015 in 80 percent of areas in which it occurs), onchocerciasis (by 2015 in Yemen, by 2020 in selected countries in Africa), and schistosomiasis (by 2020 in selected countries in Africa) • Intensified control with specific targets for 2015 and 2020 are provided for these NTDs: dengue, Buruli ulcer, cutaneous leishmaniasis, taeniasis/cysticercosis and echinococcosis/hydatidosis, foodborne trematode infections, and soil-transmitted helminthiases. In 2021, WHO updated their NTD roadmap "Together towards 2030", outlining their approach for 2021–2030. The prize was proposed by Duke University faculty Henry Grabowski, Jeffrey Moe, and David Ridley in their 2006 Health Affairs paper "Developing Drugs for Developing Countries". In 2007, United States Senators Sam Brownback (R-KS) and Sherrod Brown (D-OH) sponsored an amendment to the Food and Drug Administration Amendments Act of 2007. President George W. Bush signed the bill in September 2007. Deworming treatment Deworming treatments in infected children may have some nutritional benefit, as worms are often partially responsible for malnutrition. However, in areas where these infections are common, there is strong evidence that mass deworming campaigns do not have a positive effect on children's average nutritional status, levels of blood haemoglobin, cognitive abilities, performance at school, or survival. A systematic review, however, found that there is little or no difference in attendance in children who receive mass deworming compared to children who did not. One study found that boys were enrolled in primary school for more years than boys who were in schools that did not offer such programs. Girls in the same study were about a quarter more likely to attend secondary school if they received treatment. Both groups went on to participate in more skilled sectors of the labor market. The economic growth generated from school programs such as this may balance out the actual expenses of the program. However, the results of this study are disputed (due to a high risk of bias in the study), and the positive long-term outcomes of mass deworming remain unclear. Some neglected tropical diseases share common vectors (sandflies, black flies, and mosquitos). A four-drug rapid-impact package has been proposed that targets multiple diseases together. This package is estimated to cost US$0.40 per patient, with estimated saving of 26–47% compared to treating the diseases separately. While more research must be done in order to understand how NTDs and other diseases interact in both the vector and the human stages, safety assessments have so far produced positive results. Mass drug administration alone will not protect people from re-infection. A more holistic and integrated approach to NTDs and WASH efforts will benefit both sectors along with the communities they are aiming to serve. This is especially true in areas where more than one NTD is endemic. The plan aimed to intensify control or eliminate certain NTDs in specific regions by 2020, and referred to the NTD "roadmap" milestones from 2012 that included eradication of dracunculiasis by 2015 and of yaws by 2020, elimination of trachoma and lymphatic filariasis as public health problems by 2020, and intensified control of dengue, schistosomiasis, and soil-transmitted helminthiases. Closer collaboration between WASH and NTD programmes can lead to synergies. They can be achieved through collaborative planning, delivery and evaluation of programmes, strengthening and sharing of evidence, and using monitoring tools to improve the equity of health services. Reasons why WASH plays an important role in NTD prevention and patient care include: • A leading cause of preventable blindness is trachoma. The bacterial infection is transmitted through contact with eye-seeking flies, fingers, and fomites. Prevention components are facial cleanliness, which requires water for face washing, and environmental improvement, which includes safe disposal of excreta to reduce fly populations. • Improved sanitation prevents soil-transmitted helminthiases. It impedes fecal pathogens such as intestinal worm eggs from contaminating the environment and infecting people through contaminated food, water, dirty hands, and direct skin contact with the soil. • Improved sanitation and water management can contribute to reduced proliferation of mosquitoes that transmit diseases, such as lymphatic filariasis, dengue, and chikungunya. Breeding of the Culex mosquito, which transmits filarial parasites, is facilitated through poorly constructed latrines. Breeding of the Aedes aegypti and Aedes albopictus mosquitoes, which transmit dengue and chikungunya, can be prevented through safe storage of water. • Feces and urine that contain worm eggs can contaminate surface water and lead to transmission of schistosomiasis. This can be prevented through improved sanitation. Not only human but also animal (cow, buffalo) urine or feces can transmit some schistosome species. Therefore, it is important to protect freshwater from animals and animal waste. • Treatment of many NTDs requires clean water and hygienic conditions for healthcare facilities and households. For Guinea-worm disease, Buruli ulcer, and cutaneous leishmaniasis, wound management is needed to speed up healing and reduce disability. Lymphatic filariasis causes chronic disabilities. People who have this disease need to maintain rigorous personal hygiene with water and soap to prevent secondary infections. • NTDs that lead to permanent disabilities make tasks such as carrying water long distances or accessing toilets difficult. However, people affected by these diseases often face stigma and can be excluded from accessing water and sanitation facilities. This increases their risk of poverty and severe illness. Clean water and soap are essential for these groups to maintain personal hygiene and dignity. Therefore, additional efforts to reduce stigma and exclusion are needed. In this manner, WASH can improve the quality of life of people affected by NTDs. • In a meta-analysis, safe water was associated with significantly reduced odds of Schistosoma infection, and adequate sanitation was associated with significantly lower odds of infection with both S. mansoni and S. haematobium. • A systematic review and meta-analysis showed that better hygiene in children is associated with lower odds of trachoma. Access to sanitation was associated with 15 percent lower odds of active trachoma and 33 percent lower odds of C. trachomatis infection of the eyes. • Another systematic review and meta-analysis found a correlation between WASH access and practices, and lower odds of soil-transmitted helminthiasis infections by 33 to 77 percent. Persons who washed their hands after defecating were less than half as likely to be infected as those who did not. Traditionally, preventive chemotherapy is used as a measure of control, although this measure does not stop the transmission cycle and cannot prevent reinfection. In contrast, improved sanitation can. Pharmaceutical market Biotechnology companies in the developing world have targeted neglected tropical diseases due to a need to improve global health. Mass drug administration is considered a possible method for eradication, especially for lymphatic filariasis, onchocerciasis, and trachoma, although drug resistance is a potential problem. According to Fenwick, Pfizer donated 70 million doses of drugs in 2011 to eliminate trachoma through the International Trachoma Initiative. GlaxoSmithKline has donated two billion tablets of medicine for lymphatic filariasis and pledged 400 million deworming tablets per year for five years in 2010. Johnson & Johnson has pledged 200 million deworming tablets per year. Despite under-funding, treatment and prevention of many neglected diseases is cost-effective. The cost of treating a child for infection of soil-transmitted helminths and schistosomes (some of the main causes of neglected diseases) is less than US$0.50 per year when administered as part of school-based mass deworming by Deworm the World. This programme is recommended by Giving What We Can and the Copenhagen Consensus Centre as one of the most efficient and cost-effective solutions. The efforts of the Schistosomiasis Control Initiative to combat neglected diseases include the use of rapid-impact packages: supplying schools with packages including four or five drugs, and training teachers in how to administer them. Health Action International based in Amsterdam worked with the WHO to get snakebite envenoming on the list of neglected tropical diseases. Drugs for Neglected Disease initiative (DNDi) is one of these PDPs that has already developed new treatments for NTDs. The Sabin Vaccine Institute, founded in 1993, works to address the issues of vaccine-preventable diseases as well as NTDs. They run three main programs: Sabin Vaccine Development, Global Network for Neglected Tropical Diseases, and Vaccine Advocacy and Education. Their product development partnership affiliates them with the Texas Children's Hospital as well as the Baylor College of Medicine. Their major campaign, End7, aims to end seven of the most common NTDs (elephantiasis, river blindness, snail fever, trachoma, roundworm, whipworm, and hookworm) by 2020. Through End7, college campuses undertake fundraising and educational initiatives for the broader goals of the campaign. WIPO Re:Search was established in 2011 by the World Intellectual Property Organization in collaboration with BIO Ventures for Global Health (BVGH) and with the active participation of leading pharmaceutical companies and other private and public sector research organizations. It allows organizations to share their intellectual property, compounds, expertise, facilities, and know-how royalty-free with qualified researchers worldwide working on new solutions for NTDs, malaria, and tuberculosis. In 2013, the Government of Japan, five Japanese pharmaceutical companies, the Bill and Melinda Gates Foundation, and the UNDP established a new public–private partnership, the Global Health Innovative Technology Fund. They pledged over US$100 million to the fund over five years, to be awarded as grants to R&D partnerships across sectors in Japan and elsewhere, working to develop new drugs and vaccines for 17 neglected diseases, in addition to HIV, malaria, and tuberculosis. Affordability of the resulting drugs and vaccines is one of the key criteria for grant awards. It was endorsed by governments and organisations around the world, as well as major pharmaceutical companies including Abbott, AstraZeneca, Bayer HealthCare Pharmaceuticals, Becton Dickinson, Bristol-Myers Squibb, Eisai, Gilead Sciences, GlaxoSmithKline, Johnson & Johnson, Merck KGaA, Merck Sharp & Dohme, MSD, Novartis, Pfizer, and Sanofi. It was not a complete success, but millions of lives were saved, the burden of the infections was reduced, and 42 countries eliminated at least one disease. To commemorate the programme, WHO adopted 30 January as the World NTD Day. Kigali Declaration on Neglected Tropical Diseases The Kigali Declaration on Neglected Tropical Diseases was launched at the Kigali Summit on Malaria and Neglected Tropical Diseases (NTDs) hosted by the Government of Rwanda at its capital city Kigali on 23 June 2022. It was signed as a support for the World Health Organization's 2021–30 road map for NTDs and the target of Sustainable Development Goal 3 to end NTD epidemics; and as a follow-up project of the London Declaration . Supported by WHO, governments of the Commonwealth of Nations pledged the endorsement, along with commitments from GSK plc, Novartis, and Pfizer. Others An open-access journal dedicated to neglected tropical diseases called PLoS Neglected Tropical Diseases first began publication in 2007. One of the first large-scale initiatives to address NTDs came from a collaboration between Kenneth Warren and the Rockefeller Foundation. Ken Warren is regarded as a pioneer in neglected tropical disease research. The Great Neglected Tropical Diseases Network was a consortium of scientists from all over the world, hand-picked by Warren, working to expand the research base in neglected diseases. Many of the scientists that he recruited had not been involved in NTD research before. The network ran from 1978 to 1988. Warren's vision was to establish units within biological labs across the world, dedicated to R&D. By forming a critical mass of scientists in NTD research, he hoped to attract new students into the field. The interdisciplinary group met annually to update the community on research progress. Much of the work done by this group focused on understanding the mechanisms behind infection. At these informally structured meetings, research partnerships were formed. Warren himself encouraged these partnerships, especially if they bridged the divide between developed and developing nations. Through the Great Neglected Tropical Disease Network, a great number of scientists were brought into the field of parasitology. == Epidemiology ==

The distribution of neglected tropical disease disproportionally affects about one billion of the world's poorest populations, causing mortality, disability, and morbidity. Lack of funding, resources, and attention can result in treatable and preventable diseases causing death. Factors like political dynamics, poverty, and geographical conditions can make the delivery of NTD control programs difficult. However, the DALY has been criticized as a "systematic undervaluation" of disease burden. King asserts that DALY emphasizes the individual too much while ignoring the effects of the ecology of the disease. In order for the measure to become more valid, it may have to take the context of poverty more into account. King also emphasizes that DALYs may not capture the non-linear effects of poverty on the cost-utility analysis of disease control. The Socio-Demographic Index (SDI) and Healthy Life Expectancy (HALE) are other summary measures that can be used to take into account other factors. HALE is a metric that weights years lived and health loss before death to provide a summary of population health. SDI is a measurement that includes lag-distributed income per capita, average education, and fertility rate. Socioeconomic factors greatly influence the distribution of neglected tropical diseases, and not addressing these factors in models and measurements can lead to ineffective public health policy. == Research and development ==

NTD interventions include programs to address environmental and social determinants of health (e.g., vector control, water quality, sanitation) as well as programs offering mass drug administration for disease prevention and treatment. Drug treatments exist to confront many of the NTDs and represent some of the world's essential medicines. Despite significant health and economic improvements using available medicines, the low number of new compounds being researched and developed for NTDs is an ongoing and significant challenge. The dearth of candidates in pharmaceutical company drug pipelines is primarily attributed to the high costs of drug development and the fact that NTDs are concentrated among the world's poor. Initiatives include public-private partnerships, global R&D capacity building, priority vouchers to speed drug approval processes, open source scientific collaborations, and harmonization of global governance structures concerning NTDs. The diseases considered neglected tropical diseases vary. Some researchers no longer consider malaria, HIV, and tuberculosis to be neglected due to the amount of public attention and increased funding they have received. Outside "The Big Three", the seven most prevalent neglected tropical diseases in order of their global prevalence are ascariasis, trichuriasis, hookworm infection, schistosomiasis, lymphatic filariasis, and trachoma. the number was slightly higher, with 46 new drugs and vaccines approved (~3% of the total including HIV drugs). DiMasi, Hansen, and Grabowski calculated an average of $802 million in year 2000 dollars. Furthermore, the time that drugs are approved for use averages seven years out of the twenty years on patent, meaning a tendency for the market to focus on diseases of developed nations where high prices can be used to recoup research and development costs, and subsidize failed R&D efforts. In short, NTD research and development is considered a high investment risk, given that NTDs predominantly affect the poor in low- and middle-income countries. Additional barriers include drug safety regulatory requirements, intellectual property protection problems, and poor infrastructure for distribution and sales. Policy initiatives Public–private partnerships Governments, foundations, the non-profit sector, and the private sector have found new connections to help address market deficiencies by providing funding support and spreading both the costs and risks of NTD research and development. The proliferation of public–private partnerships (PPPs) has been recognized as a key innovation in the past decade, helping to unlock existing and new resources. Major PPPs for NTDs include: the Sabin Vaccine Institute, Norvartis Vaccines Institute for Global Health, MSD Wellcome Trust Hilleman Laboratories, Infectious Diseases Research Institute, Institut Pasteur and INSERM, WIPO Re:Search, and the International Vaccine Institute. R&D capacity building in middle-income countries Growing NTD research and development capacity in middle-income countries is an area of policy interest. A 2009 study of biotechnology companies in India, China, Brazil, and South Africa revealed 62 NTD products in development and on the market out of approximately 500 products offered (~14%). When products to fight HIV, malaria, and TB were included in the analysis, the number increased to 123 products, approximately 25% of the total products offered. Researchers have argued that, unlike most multinationals, small and mid-sized "Global South" companies see significant business opportunities in the development of NTD-related diagnostics, biologics, pharmaceuticals, and services. Open source collaboration initiatives Several companies and scientific organizations are participating in open-source initiatives to share drug data and patent information over the web, and facilitate virtual collaboration on NTD research. One rich area to explore is the wealth of genomic data resulting from the sequencing of parasite genomes. These data offer opportunities for the exploration of new therapeutic products using computational and open-source collaboration methods for drug discovery. The Tropical Disease Initiative, for example, has used large amounts of computing power to generate the protein structures for ten parasite genomes. An open-source drug bank was matched algorithmically to determine compounds with protein interaction activity, and two candidates were identified. In general, such methods may hold important opportunities for off-label use of existing approved drugs. == History ==

In 1977, Kenneth S. Warren, an American researcher, invented the concept of what is now "neglected tropical diseases". In 2005 Lorenzo Savioli, a senior United Nations civil servant, was appointed director of the "Department of Control of Neglected Tropical Diseases". The World Health Organization definition of neglected tropical disease has been criticised to be restrictive and described as a form of epistemic injustice. == See also ==